hotspot/src/cpu/s390/vm/macroAssembler_s390.cpp
changeset 42065 6032b31e3719
child 43420 a056d6465ef9
child 46272 3cee5c1f3459
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/cpu/s390/vm/macroAssembler_s390.cpp	Thu Oct 13 14:49:34 2016 +0200
@@ -0,0 +1,6691 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016 SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "asm/codeBuffer.hpp"
+#include "asm/macroAssembler.inline.hpp"
+#include "compiler/disassembler.hpp"
+#include "gc/shared/collectedHeap.inline.hpp"
+#include "interpreter/interpreter.hpp"
+#include "gc/shared/cardTableModRefBS.hpp"
+#include "memory/resourceArea.hpp"
+#include "memory/universe.hpp"
+#include "oops/klass.inline.hpp"
+#include "opto/compile.hpp"
+#include "opto/intrinsicnode.hpp"
+#include "opto/matcher.hpp"
+#include "prims/methodHandles.hpp"
+#include "registerSaver_s390.hpp"
+#include "runtime/biasedLocking.hpp"
+#include "runtime/icache.hpp"
+#include "runtime/interfaceSupport.hpp"
+#include "runtime/objectMonitor.hpp"
+#include "runtime/os.hpp"
+#include "runtime/sharedRuntime.hpp"
+#include "runtime/stubRoutines.hpp"
+#include "utilities/events.hpp"
+#include "utilities/macros.hpp"
+#if INCLUDE_ALL_GCS
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1SATBCardTableModRefBS.hpp"
+#include "gc/g1/heapRegion.hpp"
+#endif
+
+#include <ucontext.h>
+
+#define BLOCK_COMMENT(str) block_comment(str)
+#define BIND(label)        bind(label); BLOCK_COMMENT(#label ":")
+
+// Move 32-bit register if destination and source are different.
+void MacroAssembler::lr_if_needed(Register rd, Register rs) {
+  if (rs != rd) { z_lr(rd, rs); }
+}
+
+// Move register if destination and source are different.
+void MacroAssembler::lgr_if_needed(Register rd, Register rs) {
+  if (rs != rd) { z_lgr(rd, rs); }
+}
+
+// Zero-extend 32-bit register into 64-bit register if destination and source are different.
+void MacroAssembler::llgfr_if_needed(Register rd, Register rs) {
+  if (rs != rd) { z_llgfr(rd, rs); }
+}
+
+// Move float register if destination and source are different.
+void MacroAssembler::ldr_if_needed(FloatRegister rd, FloatRegister rs) {
+  if (rs != rd) { z_ldr(rd, rs); }
+}
+
+// Move integer register if destination and source are different.
+// It is assumed that shorter-than-int types are already
+// appropriately sign-extended.
+void MacroAssembler::move_reg_if_needed(Register dst, BasicType dst_type, Register src,
+                                        BasicType src_type) {
+  assert((dst_type != T_FLOAT) && (dst_type != T_DOUBLE), "use move_freg for float types");
+  assert((src_type != T_FLOAT) && (src_type != T_DOUBLE), "use move_freg for float types");
+
+  if (dst_type == src_type) {
+    lgr_if_needed(dst, src); // Just move all 64 bits.
+    return;
+  }
+
+  switch (dst_type) {
+    // Do not support these types for now.
+    //  case T_BOOLEAN:
+    case T_BYTE:  // signed byte
+      switch (src_type) {
+        case T_INT:
+          z_lgbr(dst, src);
+          break;
+        default:
+          ShouldNotReachHere();
+      }
+      return;
+
+    case T_CHAR:
+    case T_SHORT:
+      switch (src_type) {
+        case T_INT:
+          if (dst_type == T_CHAR) {
+            z_llghr(dst, src);
+          } else {
+            z_lghr(dst, src);
+          }
+          break;
+        default:
+          ShouldNotReachHere();
+      }
+      return;
+
+    case T_INT:
+      switch (src_type) {
+        case T_BOOLEAN:
+        case T_BYTE:
+        case T_CHAR:
+        case T_SHORT:
+        case T_INT:
+        case T_LONG:
+        case T_OBJECT:
+        case T_ARRAY:
+        case T_VOID:
+        case T_ADDRESS:
+          lr_if_needed(dst, src);
+          // llgfr_if_needed(dst, src);  // zero-extend (in case we need to find a bug).
+          return;
+
+        default:
+          assert(false, "non-integer src type");
+          return;
+      }
+    case T_LONG:
+      switch (src_type) {
+        case T_BOOLEAN:
+        case T_BYTE:
+        case T_CHAR:
+        case T_SHORT:
+        case T_INT:
+          z_lgfr(dst, src); // sign extension
+          return;
+
+        case T_LONG:
+        case T_OBJECT:
+        case T_ARRAY:
+        case T_VOID:
+        case T_ADDRESS:
+          lgr_if_needed(dst, src);
+          return;
+
+        default:
+          assert(false, "non-integer src type");
+          return;
+      }
+      return;
+    case T_OBJECT:
+    case T_ARRAY:
+    case T_VOID:
+    case T_ADDRESS:
+      switch (src_type) {
+        // These types don't make sense to be converted to pointers:
+        //      case T_BOOLEAN:
+        //      case T_BYTE:
+        //      case T_CHAR:
+        //      case T_SHORT:
+
+        case T_INT:
+          z_llgfr(dst, src); // zero extension
+          return;
+
+        case T_LONG:
+        case T_OBJECT:
+        case T_ARRAY:
+        case T_VOID:
+        case T_ADDRESS:
+          lgr_if_needed(dst, src);
+          return;
+
+        default:
+          assert(false, "non-integer src type");
+          return;
+      }
+      return;
+    default:
+      assert(false, "non-integer dst type");
+      return;
+  }
+}
+
+// Move float register if destination and source are different.
+void MacroAssembler::move_freg_if_needed(FloatRegister dst, BasicType dst_type,
+                                         FloatRegister src, BasicType src_type) {
+  assert((dst_type == T_FLOAT) || (dst_type == T_DOUBLE), "use move_reg for int types");
+  assert((src_type == T_FLOAT) || (src_type == T_DOUBLE), "use move_reg for int types");
+  if (dst_type == src_type) {
+    ldr_if_needed(dst, src); // Just move all 64 bits.
+  } else {
+    switch (dst_type) {
+      case T_FLOAT:
+        assert(src_type == T_DOUBLE, "invalid float type combination");
+        z_ledbr(dst, src);
+        return;
+      case T_DOUBLE:
+        assert(src_type == T_FLOAT, "invalid float type combination");
+        z_ldebr(dst, src);
+        return;
+      default:
+        assert(false, "non-float dst type");
+        return;
+    }
+  }
+}
+
+// Optimized emitter for reg to mem operations.
+// Uses modern instructions if running on modern hardware, classic instructions
+// otherwise. Prefers (usually shorter) classic instructions if applicable.
+// Data register (reg) cannot be used as work register.
+//
+// Don't rely on register locking, instead pass a scratch register (Z_R0 by default).
+// CAUTION! Passing registers >= Z_R2 may produce bad results on old CPUs!
+void MacroAssembler::freg2mem_opt(FloatRegister reg,
+                                  int64_t       disp,
+                                  Register      index,
+                                  Register      base,
+                                  void (MacroAssembler::*modern) (FloatRegister, int64_t, Register, Register),
+                                  void (MacroAssembler::*classic)(FloatRegister, int64_t, Register, Register),
+                                  Register      scratch) {
+  index = (index == noreg) ? Z_R0 : index;
+  if (Displacement::is_shortDisp(disp)) {
+    (this->*classic)(reg, disp, index, base);
+  } else {
+    if (Displacement::is_validDisp(disp)) {
+      (this->*modern)(reg, disp, index, base);
+    } else {
+      if (scratch != Z_R0 && scratch != Z_R1) {
+        (this->*modern)(reg, disp, index, base);      // Will fail with disp out of range.
+      } else {
+        if (scratch != Z_R0) {   // scratch == Z_R1
+          if ((scratch == index) || (index == base)) {
+            (this->*modern)(reg, disp, index, base);  // Will fail with disp out of range.
+          } else {
+            add2reg(scratch, disp, base);
+            (this->*classic)(reg, 0, index, scratch);
+            if (base == scratch) {
+              add2reg(base, -disp);  // Restore base.
+            }
+          }
+        } else {   // scratch == Z_R0
+          z_lgr(scratch, base);
+          add2reg(base, disp);
+          (this->*classic)(reg, 0, index, base);
+          z_lgr(base, scratch);      // Restore base.
+        }
+      }
+    }
+  }
+}
+
+void MacroAssembler::freg2mem_opt(FloatRegister reg, const Address &a, bool is_double) {
+  if (is_double) {
+    freg2mem_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_FFUN(z_stdy), CLASSIC_FFUN(z_std));
+  } else {
+    freg2mem_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_FFUN(z_stey), CLASSIC_FFUN(z_ste));
+  }
+}
+
+// Optimized emitter for mem to reg operations.
+// Uses modern instructions if running on modern hardware, classic instructions
+// otherwise. Prefers (usually shorter) classic instructions if applicable.
+// data register (reg) cannot be used as work register.
+//
+// Don't rely on register locking, instead pass a scratch register (Z_R0 by default).
+// CAUTION! Passing registers >= Z_R2 may produce bad results on old CPUs!
+void MacroAssembler::mem2freg_opt(FloatRegister reg,
+                                  int64_t       disp,
+                                  Register      index,
+                                  Register      base,
+                                  void (MacroAssembler::*modern) (FloatRegister, int64_t, Register, Register),
+                                  void (MacroAssembler::*classic)(FloatRegister, int64_t, Register, Register),
+                                  Register      scratch) {
+  index = (index == noreg) ? Z_R0 : index;
+  if (Displacement::is_shortDisp(disp)) {
+    (this->*classic)(reg, disp, index, base);
+  } else {
+    if (Displacement::is_validDisp(disp)) {
+      (this->*modern)(reg, disp, index, base);
+    } else {
+      if (scratch != Z_R0 && scratch != Z_R1) {
+        (this->*modern)(reg, disp, index, base);      // Will fail with disp out of range.
+      } else {
+        if (scratch != Z_R0) {   // scratch == Z_R1
+          if ((scratch == index) || (index == base)) {
+            (this->*modern)(reg, disp, index, base);  // Will fail with disp out of range.
+          } else {
+            add2reg(scratch, disp, base);
+            (this->*classic)(reg, 0, index, scratch);
+            if (base == scratch) {
+              add2reg(base, -disp);  // Restore base.
+            }
+          }
+        } else {   // scratch == Z_R0
+          z_lgr(scratch, base);
+          add2reg(base, disp);
+          (this->*classic)(reg, 0, index, base);
+          z_lgr(base, scratch);      // Restore base.
+        }
+      }
+    }
+  }
+}
+
+void MacroAssembler::mem2freg_opt(FloatRegister reg, const Address &a, bool is_double) {
+  if (is_double) {
+    mem2freg_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_FFUN(z_ldy), CLASSIC_FFUN(z_ld));
+  } else {
+    mem2freg_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_FFUN(z_ley), CLASSIC_FFUN(z_le));
+  }
+}
+
+// Optimized emitter for reg to mem operations.
+// Uses modern instructions if running on modern hardware, classic instructions
+// otherwise. Prefers (usually shorter) classic instructions if applicable.
+// Data register (reg) cannot be used as work register.
+//
+// Don't rely on register locking, instead pass a scratch register
+// (Z_R0 by default)
+// CAUTION! passing registers >= Z_R2 may produce bad results on old CPUs!
+void MacroAssembler::reg2mem_opt(Register reg,
+                                 int64_t  disp,
+                                 Register index,
+                                 Register base,
+                                 void (MacroAssembler::*modern) (Register, int64_t, Register, Register),
+                                 void (MacroAssembler::*classic)(Register, int64_t, Register, Register),
+                                 Register scratch) {
+  index = (index == noreg) ? Z_R0 : index;
+  if (Displacement::is_shortDisp(disp)) {
+    (this->*classic)(reg, disp, index, base);
+  } else {
+    if (Displacement::is_validDisp(disp)) {
+      (this->*modern)(reg, disp, index, base);
+    } else {
+      if (scratch != Z_R0 && scratch != Z_R1) {
+        (this->*modern)(reg, disp, index, base);      // Will fail with disp out of range.
+      } else {
+        if (scratch != Z_R0) {   // scratch == Z_R1
+          if ((scratch == index) || (index == base)) {
+            (this->*modern)(reg, disp, index, base);  // Will fail with disp out of range.
+          } else {
+            add2reg(scratch, disp, base);
+            (this->*classic)(reg, 0, index, scratch);
+            if (base == scratch) {
+              add2reg(base, -disp);  // Restore base.
+            }
+          }
+        } else {   // scratch == Z_R0
+          if ((scratch == reg) || (scratch == base) || (reg == base)) {
+            (this->*modern)(reg, disp, index, base);  // Will fail with disp out of range.
+          } else {
+            z_lgr(scratch, base);
+            add2reg(base, disp);
+            (this->*classic)(reg, 0, index, base);
+            z_lgr(base, scratch);    // Restore base.
+          }
+        }
+      }
+    }
+  }
+}
+
+int MacroAssembler::reg2mem_opt(Register reg, const Address &a, bool is_double) {
+  int store_offset = offset();
+  if (is_double) {
+    reg2mem_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_IFUN(z_stg), CLASSIC_IFUN(z_stg));
+  } else {
+    reg2mem_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_IFUN(z_sty), CLASSIC_IFUN(z_st));
+  }
+  return store_offset;
+}
+
+// Optimized emitter for mem to reg operations.
+// Uses modern instructions if running on modern hardware, classic instructions
+// otherwise. Prefers (usually shorter) classic instructions if applicable.
+// Data register (reg) will be used as work register where possible.
+void MacroAssembler::mem2reg_opt(Register reg,
+                                 int64_t  disp,
+                                 Register index,
+                                 Register base,
+                                 void (MacroAssembler::*modern) (Register, int64_t, Register, Register),
+                                 void (MacroAssembler::*classic)(Register, int64_t, Register, Register)) {
+  index = (index == noreg) ? Z_R0 : index;
+  if (Displacement::is_shortDisp(disp)) {
+    (this->*classic)(reg, disp, index, base);
+  } else {
+    if (Displacement::is_validDisp(disp)) {
+      (this->*modern)(reg, disp, index, base);
+    } else {
+      if ((reg == index) && (reg == base)) {
+        z_sllg(reg, reg, 1);
+        add2reg(reg, disp);
+        (this->*classic)(reg, 0, noreg, reg);
+      } else if ((reg == index) && (reg != Z_R0)) {
+        add2reg(reg, disp);
+        (this->*classic)(reg, 0, reg, base);
+      } else if (reg == base) {
+        add2reg(reg, disp);
+        (this->*classic)(reg, 0, index, reg);
+      } else if (reg != Z_R0) {
+        add2reg(reg, disp, base);
+        (this->*classic)(reg, 0, index, reg);
+      } else { // reg == Z_R0 && reg != base here
+        add2reg(base, disp);
+        (this->*classic)(reg, 0, index, base);
+        add2reg(base, -disp);
+      }
+    }
+  }
+}
+
+void MacroAssembler::mem2reg_opt(Register reg, const Address &a, bool is_double) {
+  if (is_double) {
+    z_lg(reg, a);
+  } else {
+    mem2reg_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_IFUN(z_ly), CLASSIC_IFUN(z_l));
+  }
+}
+
+void MacroAssembler::mem2reg_signed_opt(Register reg, const Address &a) {
+  mem2reg_opt(reg, a.disp20(), a.indexOrR0(), a.baseOrR0(), MODERN_IFUN(z_lgf), CLASSIC_IFUN(z_lgf));
+}
+
+void MacroAssembler::and_imm(Register r, long mask,
+                             Register tmp /* = Z_R0 */,
+                             bool wide    /* = false */) {
+  assert(wide || Immediate::is_simm32(mask), "mask value too large");
+
+  if (!wide) {
+    z_nilf(r, mask);
+    return;
+  }
+
+  assert(r != tmp, " need a different temporary register !");
+  load_const_optimized(tmp, mask);
+  z_ngr(r, tmp);
+}
+
+// Calculate the 1's complement.
+// Note: The condition code is neither preserved nor correctly set by this code!!!
+// Note: (wide == false) does not protect the high order half of the target register
+//       from alteration. It only serves as optimization hint for 32-bit results.
+void MacroAssembler::not_(Register r1, Register r2, bool wide) {
+
+  if ((r2 == noreg) || (r2 == r1)) { // Calc 1's complement in place.
+    z_xilf(r1, -1);
+    if (wide) {
+      z_xihf(r1, -1);
+    }
+  } else { // Distinct src and dst registers.
+    if (VM_Version::has_DistinctOpnds()) {
+      load_const_optimized(r1, -1);
+      z_xgrk(r1, r2, r1);
+    } else {
+      if (wide) {
+        z_lgr(r1, r2);
+        z_xilf(r1, -1);
+        z_xihf(r1, -1);
+      } else {
+        z_lr(r1, r2);
+        z_xilf(r1, -1);
+      }
+    }
+  }
+}
+
+unsigned long MacroAssembler::create_mask(int lBitPos, int rBitPos) {
+  assert(lBitPos >=  0,      "zero is  leftmost bit position");
+  assert(rBitPos <= 63,      "63   is rightmost bit position");
+  assert(lBitPos <= rBitPos, "inverted selection interval");
+  return (lBitPos == 0 ? (unsigned long)(-1L) : ((1UL<<(63-lBitPos+1))-1)) & (~((1UL<<(63-rBitPos))-1));
+}
+
+// Helper function for the "Rotate_then_<logicalOP>" emitters.
+// Rotate src, then mask register contents such that only bits in range survive.
+// For oneBits == false, all bits not in range are set to 0. Useful for deleting all bits outside range.
+// For oneBits == true,  all bits not in range are set to 1. Useful for preserving all bits outside range.
+// The caller must ensure that the selected range only contains bits with defined value.
+void MacroAssembler::rotate_then_mask(Register dst, Register src, int lBitPos, int rBitPos,
+                                      int nRotate, bool src32bit, bool dst32bit, bool oneBits) {
+  assert(!(dst32bit && lBitPos < 32), "selection interval out of range for int destination");
+  bool sll4rll = (nRotate >= 0) && (nRotate <= (63-rBitPos)); // Substitute SLL(G) for RLL(G).
+  bool srl4rll = (nRotate <  0) && (-nRotate <= lBitPos);     // Substitute SRL(G) for RLL(G).
+  //  Pre-determine which parts of dst will be zero after shift/rotate.
+  bool llZero  =  sll4rll && (nRotate >= 16);
+  bool lhZero  = (sll4rll && (nRotate >= 32)) || (srl4rll && (nRotate <= -48));
+  bool lfZero  = llZero && lhZero;
+  bool hlZero  = (sll4rll && (nRotate >= 48)) || (srl4rll && (nRotate <= -32));
+  bool hhZero  =                                 (srl4rll && (nRotate <= -16));
+  bool hfZero  = hlZero && hhZero;
+
+  // rotate then mask src operand.
+  // if oneBits == true,  all bits outside selected range are 1s.
+  // if oneBits == false, all bits outside selected range are 0s.
+  if (src32bit) {   // There might be garbage in the upper 32 bits which will get masked away.
+    if (dst32bit) {
+      z_rll(dst, src, nRotate);   // Copy and rotate, upper half of reg remains undisturbed.
+    } else {
+      if      (sll4rll) { z_sllg(dst, src,  nRotate); }
+      else if (srl4rll) { z_srlg(dst, src, -nRotate); }
+      else              { z_rllg(dst, src,  nRotate); }
+    }
+  } else {
+    if      (sll4rll) { z_sllg(dst, src,  nRotate); }
+    else if (srl4rll) { z_srlg(dst, src, -nRotate); }
+    else              { z_rllg(dst, src,  nRotate); }
+  }
+
+  unsigned long  range_mask    = create_mask(lBitPos, rBitPos);
+  unsigned int   range_mask_h  = (unsigned int)(range_mask >> 32);
+  unsigned int   range_mask_l  = (unsigned int)range_mask;
+  unsigned short range_mask_hh = (unsigned short)(range_mask >> 48);
+  unsigned short range_mask_hl = (unsigned short)(range_mask >> 32);
+  unsigned short range_mask_lh = (unsigned short)(range_mask >> 16);
+  unsigned short range_mask_ll = (unsigned short)range_mask;
+  // Works for z9 and newer H/W.
+  if (oneBits) {
+    if ((~range_mask_l) != 0)                { z_oilf(dst, ~range_mask_l); } // All bits outside range become 1s.
+    if (((~range_mask_h) != 0) && !dst32bit) { z_oihf(dst, ~range_mask_h); }
+  } else {
+    // All bits outside range become 0s
+    if (((~range_mask_l) != 0) &&              !lfZero) {
+      z_nilf(dst, range_mask_l);
+    }
+    if (((~range_mask_h) != 0) && !dst32bit && !hfZero) {
+      z_nihf(dst, range_mask_h);
+    }
+  }
+}
+
+// Rotate src, then insert selected range from rotated src into dst.
+// Clear dst before, if requested.
+void MacroAssembler::rotate_then_insert(Register dst, Register src, int lBitPos, int rBitPos,
+                                        int nRotate, bool clear_dst) {
+  // This version does not depend on src being zero-extended int2long.
+  nRotate &= 0x003f;                                       // For risbg, pretend it's an unsigned value.
+  z_risbg(dst, src, lBitPos, rBitPos, nRotate, clear_dst); // Rotate, then insert selected, clear the rest.
+}
+
+// Rotate src, then and selected range from rotated src into dst.
+// Set condition code only if so requested. Otherwise it is unpredictable.
+// See performance note in macroAssembler_s390.hpp for important information.
+void MacroAssembler::rotate_then_and(Register dst, Register src, int lBitPos, int rBitPos,
+                                     int nRotate, bool test_only) {
+  guarantee(!test_only, "Emitter not fit for test_only instruction variant.");
+  // This version does not depend on src being zero-extended int2long.
+  nRotate &= 0x003f;                                       // For risbg, pretend it's an unsigned value.
+  z_rxsbg(dst, src, lBitPos, rBitPos, nRotate, test_only); // Rotate, then xor selected.
+}
+
+// Rotate src, then or selected range from rotated src into dst.
+// Set condition code only if so requested. Otherwise it is unpredictable.
+// See performance note in macroAssembler_s390.hpp for important information.
+void MacroAssembler::rotate_then_or(Register dst, Register src,  int  lBitPos,  int  rBitPos,
+                                    int nRotate, bool test_only) {
+  guarantee(!test_only, "Emitter not fit for test_only instruction variant.");
+  // This version does not depend on src being zero-extended int2long.
+  nRotate &= 0x003f;                                       // For risbg, pretend it's an unsigned value.
+  z_rosbg(dst, src, lBitPos, rBitPos, nRotate, test_only); // Rotate, then xor selected.
+}
+
+// Rotate src, then xor selected range from rotated src into dst.
+// Set condition code only if so requested. Otherwise it is unpredictable.
+// See performance note in macroAssembler_s390.hpp for important information.
+void MacroAssembler::rotate_then_xor(Register dst, Register src,  int  lBitPos,  int  rBitPos,
+                                     int nRotate, bool test_only) {
+  guarantee(!test_only, "Emitter not fit for test_only instruction variant.");
+    // This version does not depend on src being zero-extended int2long.
+  nRotate &= 0x003f;                                       // For risbg, pretend it's an unsigned value.
+  z_rxsbg(dst, src, lBitPos, rBitPos, nRotate, test_only); // Rotate, then xor selected.
+}
+
+void MacroAssembler::add64(Register r1, RegisterOrConstant inc) {
+  if (inc.is_register()) {
+    z_agr(r1, inc.as_register());
+  } else { // constant
+    intptr_t imm = inc.as_constant();
+    add2reg(r1, imm);
+  }
+}
+// Helper function to multiply the 64bit contents of a register by a 16bit constant.
+// The optimization tries to avoid the mghi instruction, since it uses the FPU for
+// calculation and is thus rather slow.
+//
+// There is no handling for special cases, e.g. cval==0 or cval==1.
+//
+// Returns len of generated code block.
+unsigned int MacroAssembler::mul_reg64_const16(Register rval, Register work, int cval) {
+  int block_start = offset();
+
+  bool sign_flip = cval < 0;
+  cval = sign_flip ? -cval : cval;
+
+  BLOCK_COMMENT("Reg64*Con16 {");
+
+  int bit1 = cval & -cval;
+  if (bit1 == cval) {
+    z_sllg(rval, rval, exact_log2(bit1));
+    if (sign_flip) { z_lcgr(rval, rval); }
+  } else {
+    int bit2 = (cval-bit1) & -(cval-bit1);
+    if ((bit1+bit2) == cval) {
+      z_sllg(work, rval, exact_log2(bit1));
+      z_sllg(rval, rval, exact_log2(bit2));
+      z_agr(rval, work);
+      if (sign_flip) { z_lcgr(rval, rval); }
+    } else {
+      if (sign_flip) { z_mghi(rval, -cval); }
+      else           { z_mghi(rval,  cval); }
+    }
+  }
+  BLOCK_COMMENT("} Reg64*Con16");
+
+  int block_end = offset();
+  return block_end - block_start;
+}
+
+// Generic operation r1 := r2 + imm.
+//
+// Should produce the best code for each supported CPU version.
+// r2 == noreg yields r1 := r1 + imm
+// imm == 0 emits either no instruction or r1 := r2 !
+// NOTES: 1) Don't use this function where fixed sized
+//           instruction sequences are required!!!
+//        2) Don't use this function if condition code
+//           setting is required!
+//        3) Despite being declared as int64_t, the parameter imm
+//           must be a simm_32 value (= signed 32-bit integer).
+void MacroAssembler::add2reg(Register r1, int64_t imm, Register r2) {
+  assert(Immediate::is_simm32(imm), "probably an implicit conversion went wrong");
+
+  if (r2 == noreg) { r2 = r1; }
+
+  // Handle special case imm == 0.
+  if (imm == 0) {
+    lgr_if_needed(r1, r2);
+    // Nothing else to do.
+    return;
+  }
+
+  if (!PreferLAoverADD || (r2 == Z_R0)) {
+    bool distinctOpnds = VM_Version::has_DistinctOpnds();
+
+    // Can we encode imm in 16 bits signed?
+    if (Immediate::is_simm16(imm)) {
+      if (r1 == r2) {
+        z_aghi(r1, imm);
+        return;
+      }
+      if (distinctOpnds) {
+        z_aghik(r1, r2, imm);
+        return;
+      }
+      z_lgr(r1, r2);
+      z_aghi(r1, imm);
+      return;
+    }
+  } else {
+    // Can we encode imm in 12 bits unsigned?
+    if (Displacement::is_shortDisp(imm)) {
+      z_la(r1, imm, r2);
+      return;
+    }
+    // Can we encode imm in 20 bits signed?
+    if (Displacement::is_validDisp(imm)) {
+      // Always use LAY instruction, so we don't need the tmp register.
+      z_lay(r1, imm, r2);
+      return;
+    }
+
+  }
+
+  // Can handle it (all possible values) with long immediates.
+  lgr_if_needed(r1, r2);
+  z_agfi(r1, imm);
+}
+
+// Generic operation r := b + x + d
+//
+// Addition of several operands with address generation semantics - sort of:
+//  - no restriction on the registers. Any register will do for any operand.
+//  - x == noreg: operand will be disregarded.
+//  - b == noreg: will use (contents of) result reg as operand (r := r + d).
+//  - x == Z_R0:  just disregard
+//  - b == Z_R0:  use as operand. This is not address generation semantics!!!
+//
+// The same restrictions as on add2reg() are valid!!!
+void MacroAssembler::add2reg_with_index(Register r, int64_t d, Register x, Register b) {
+  assert(Immediate::is_simm32(d), "probably an implicit conversion went wrong");
+
+  if (x == noreg) { x = Z_R0; }
+  if (b == noreg) { b = r; }
+
+  // Handle special case x == R0.
+  if (x == Z_R0) {
+    // Can simply add the immediate value to the base register.
+    add2reg(r, d, b);
+    return;
+  }
+
+  if (!PreferLAoverADD || (b == Z_R0)) {
+    bool distinctOpnds = VM_Version::has_DistinctOpnds();
+    // Handle special case d == 0.
+    if (d == 0) {
+      if (b == x)        { z_sllg(r, b, 1); return; }
+      if (r == x)        { z_agr(r, b);     return; }
+      if (r == b)        { z_agr(r, x);     return; }
+      if (distinctOpnds) { z_agrk(r, x, b); return; }
+      z_lgr(r, b);
+      z_agr(r, x);
+    } else {
+      if (x == b)             { z_sllg(r, x, 1); }
+      else if (r == x)        { z_agr(r, b); }
+      else if (r == b)        { z_agr(r, x); }
+      else if (distinctOpnds) { z_agrk(r, x, b); }
+      else {
+        z_lgr(r, b);
+        z_agr(r, x);
+      }
+      add2reg(r, d);
+    }
+  } else {
+    // Can we encode imm in 12 bits unsigned?
+    if (Displacement::is_shortDisp(d)) {
+      z_la(r, d, x, b);
+      return;
+    }
+    // Can we encode imm in 20 bits signed?
+    if (Displacement::is_validDisp(d)) {
+      z_lay(r, d, x, b);
+      return;
+    }
+    z_la(r, 0, x, b);
+    add2reg(r, d);
+  }
+}
+
+// Generic emitter (32bit) for direct memory increment.
+// For optimal code, do not specify Z_R0 as temp register.
+void MacroAssembler::add2mem_32(const Address &a, int64_t imm, Register tmp) {
+  if (VM_Version::has_MemWithImmALUOps() && Immediate::is_simm8(imm)) {
+    z_asi(a, imm);
+  } else {
+    z_lgf(tmp, a);
+    add2reg(tmp, imm);
+    z_st(tmp, a);
+  }
+}
+
+void MacroAssembler::add2mem_64(const Address &a, int64_t imm, Register tmp) {
+  if (VM_Version::has_MemWithImmALUOps() && Immediate::is_simm8(imm)) {
+    z_agsi(a, imm);
+  } else {
+    z_lg(tmp, a);
+    add2reg(tmp, imm);
+    z_stg(tmp, a);
+  }
+}
+
+void MacroAssembler::load_sized_value(Register dst, Address src, size_t size_in_bytes, bool is_signed) {
+  switch (size_in_bytes) {
+    case  8: z_lg(dst, src); break;
+    case  4: is_signed ? z_lgf(dst, src) : z_llgf(dst, src); break;
+    case  2: is_signed ? z_lgh(dst, src) : z_llgh(dst, src); break;
+    case  1: is_signed ? z_lgb(dst, src) : z_llgc(dst, src); break;
+    default: ShouldNotReachHere();
+  }
+}
+
+void MacroAssembler::store_sized_value(Register src, Address dst, size_t size_in_bytes) {
+  switch (size_in_bytes) {
+    case  8: z_stg(src, dst); break;
+    case  4: z_st(src, dst); break;
+    case  2: z_sth(src, dst); break;
+    case  1: z_stc(src, dst); break;
+    default: ShouldNotReachHere();
+  }
+}
+
+// Split a si20 offset (20bit, signed) into an ui12 offset (12bit, unsigned) and
+// a high-order summand in register tmp.
+//
+// return value: <  0: No split required, si20 actually has property uimm12.
+//               >= 0: Split performed. Use return value as uimm12 displacement and
+//                     tmp as index register.
+int MacroAssembler::split_largeoffset(int64_t si20_offset, Register tmp, bool fixed_codelen, bool accumulate) {
+  assert(Immediate::is_simm20(si20_offset), "sanity");
+  int lg_off = (int)si20_offset &  0x0fff; // Punch out low-order 12 bits, always positive.
+  int ll_off = (int)si20_offset & ~0x0fff; // Force low-order 12 bits to zero.
+  assert((Displacement::is_shortDisp(si20_offset) && (ll_off == 0)) ||
+         !Displacement::is_shortDisp(si20_offset), "unexpected offset values");
+  assert((lg_off+ll_off) == si20_offset, "offset splitup error");
+
+  Register work = accumulate? Z_R0 : tmp;
+
+  if (fixed_codelen) {          // Len of code = 10 = 4 + 6.
+    z_lghi(work, ll_off>>12);   // Implicit sign extension.
+    z_slag(work, work, 12);
+  } else {                      // Len of code = 0..10.
+    if (ll_off == 0) { return -1; }
+    // ll_off has 8 significant bits (at most) plus sign.
+    if ((ll_off & 0x0000f000) == 0) {    // Non-zero bits only in upper halfbyte.
+      z_llilh(work, ll_off >> 16);
+      if (ll_off < 0) {                  // Sign-extension required.
+        z_lgfr(work, work);
+      }
+    } else {
+      if ((ll_off & 0x000f0000) == 0) {  // Non-zero bits only in lower halfbyte.
+        z_llill(work, ll_off);
+      } else {                           // Non-zero bits in both halfbytes.
+        z_lghi(work, ll_off>>12);        // Implicit sign extension.
+        z_slag(work, work, 12);
+      }
+    }
+  }
+  if (accumulate) { z_algr(tmp, work); } // len of code += 4
+  return lg_off;
+}
+
+void MacroAssembler::load_float_largeoffset(FloatRegister t, int64_t si20, Register a, Register tmp) {
+  if (Displacement::is_validDisp(si20)) {
+    z_ley(t, si20, a);
+  } else {
+    // Fixed_codelen = true is a simple way to ensure that the size of load_float_largeoffset
+    // does not depend on si20 (scratch buffer emit size == code buffer emit size for constant
+    // pool loads).
+    bool accumulate    = true;
+    bool fixed_codelen = true;
+    Register work;
+
+    if (fixed_codelen) {
+      z_lgr(tmp, a);  // Lgr_if_needed not applicable due to fixed_codelen.
+    } else {
+      accumulate = (a == tmp);
+    }
+    work = tmp;
+
+    int disp12 = split_largeoffset(si20, work, fixed_codelen, accumulate);
+    if (disp12 < 0) {
+      z_le(t, si20, work);
+    } else {
+      if (accumulate) {
+        z_le(t, disp12, work);
+      } else {
+        z_le(t, disp12, work, a);
+      }
+    }
+  }
+}
+
+void MacroAssembler::load_double_largeoffset(FloatRegister t, int64_t si20, Register a, Register tmp) {
+  if (Displacement::is_validDisp(si20)) {
+    z_ldy(t, si20, a);
+  } else {
+    // Fixed_codelen = true is a simple way to ensure that the size of load_double_largeoffset
+    // does not depend on si20 (scratch buffer emit size == code buffer emit size for constant
+    // pool loads).
+    bool accumulate    = true;
+    bool fixed_codelen = true;
+    Register work;
+
+    if (fixed_codelen) {
+      z_lgr(tmp, a);  // Lgr_if_needed not applicable due to fixed_codelen.
+    } else {
+      accumulate = (a == tmp);
+    }
+    work = tmp;
+
+    int disp12 = split_largeoffset(si20, work, fixed_codelen, accumulate);
+    if (disp12 < 0) {
+      z_ld(t, si20, work);
+    } else {
+      if (accumulate) {
+        z_ld(t, disp12, work);
+      } else {
+        z_ld(t, disp12, work, a);
+      }
+    }
+  }
+}
+
+// PCrelative TOC access.
+// Returns distance (in bytes) from current position to start of consts section.
+// Returns 0 (zero) if no consts section exists or if it has size zero.
+long MacroAssembler::toc_distance() {
+  CodeSection* cs = code()->consts();
+  return (long)((cs != NULL) ? cs->start()-pc() : 0);
+}
+
+// Implementation on x86/sparc assumes that constant and instruction section are
+// adjacent, but this doesn't hold. Two special situations may occur, that we must
+// be able to handle:
+//   1. const section may be located apart from the inst section.
+//   2. const section may be empty
+// In both cases, we use the const section's start address to compute the "TOC",
+// this seems to occur only temporarily; in the final step we always seem to end up
+// with the pc-relatice variant.
+//
+// PC-relative offset could be +/-2**32 -> use long for disp
+// Furthermore: makes no sense to have special code for
+// adjacent const and inst sections.
+void MacroAssembler::load_toc(Register Rtoc) {
+  // Simply use distance from start of const section (should be patched in the end).
+  long disp = toc_distance();
+
+  RelocationHolder rspec = internal_word_Relocation::spec(pc() + disp);
+  relocate(rspec);
+  z_larl(Rtoc, RelAddr::pcrel_off32(disp));  // Offset is in halfwords.
+}
+
+// PCrelative TOC access.
+// Load from anywhere pcrelative (with relocation of load instr)
+void MacroAssembler::load_long_pcrelative(Register Rdst, address dataLocation) {
+  address          pc             = this->pc();
+  ptrdiff_t        total_distance = dataLocation - pc;
+  RelocationHolder rspec          = internal_word_Relocation::spec(dataLocation);
+
+  assert((total_distance & 0x01L) == 0, "halfword alignment is mandatory");
+  assert(total_distance != 0, "sanity");
+
+  // Some extra safety net.
+  if (!RelAddr::is_in_range_of_RelAddr32(total_distance)) {
+    guarantee(RelAddr::is_in_range_of_RelAddr32(total_distance), "too far away");
+  }
+
+  (this)->relocate(rspec, relocInfo::pcrel_addr_format);
+  z_lgrl(Rdst, RelAddr::pcrel_off32(total_distance));
+}
+
+
+// PCrelative TOC access.
+// Load from anywhere pcrelative (with relocation of load instr)
+// loaded addr has to be relocated when added to constant pool.
+void MacroAssembler::load_addr_pcrelative(Register Rdst, address addrLocation) {
+  address          pc             = this->pc();
+  ptrdiff_t        total_distance = addrLocation - pc;
+  RelocationHolder rspec          = internal_word_Relocation::spec(addrLocation);
+
+  assert((total_distance & 0x01L) == 0, "halfword alignment is mandatory");
+
+  // Some extra safety net.
+  if (!RelAddr::is_in_range_of_RelAddr32(total_distance)) {
+    guarantee(RelAddr::is_in_range_of_RelAddr32(total_distance), "too far away");
+  }
+
+  (this)->relocate(rspec, relocInfo::pcrel_addr_format);
+  z_lgrl(Rdst, RelAddr::pcrel_off32(total_distance));
+}
+
+// Generic operation: load a value from memory and test.
+// CondCode indicates the sign (<0, ==0, >0) of the loaded value.
+void MacroAssembler::load_and_test_byte(Register dst, const Address &a) {
+  z_lb(dst, a);
+  z_ltr(dst, dst);
+}
+
+void MacroAssembler::load_and_test_short(Register dst, const Address &a) {
+  int64_t disp = a.disp20();
+  if (Displacement::is_shortDisp(disp)) {
+    z_lh(dst, a);
+  } else if (Displacement::is_longDisp(disp)) {
+    z_lhy(dst, a);
+  } else {
+    guarantee(false, "displacement out of range");
+  }
+  z_ltr(dst, dst);
+}
+
+void MacroAssembler::load_and_test_int(Register dst, const Address &a) {
+  z_lt(dst, a);
+}
+
+void MacroAssembler::load_and_test_int2long(Register dst, const Address &a) {
+  z_ltgf(dst, a);
+}
+
+void MacroAssembler::load_and_test_long(Register dst, const Address &a) {
+  z_ltg(dst, a);
+}
+
+// Test a bit in memory.
+void MacroAssembler::testbit(const Address &a, unsigned int bit) {
+  assert(a.index() == noreg, "no index reg allowed in testbit");
+  if (bit <= 7) {
+    z_tm(a.disp() + 3, a.base(), 1 << bit);
+  } else if (bit <= 15) {
+    z_tm(a.disp() + 2, a.base(), 1 << (bit - 8));
+  } else if (bit <= 23) {
+    z_tm(a.disp() + 1, a.base(), 1 << (bit - 16));
+  } else if (bit <= 31) {
+    z_tm(a.disp() + 0, a.base(), 1 << (bit - 24));
+  } else {
+    ShouldNotReachHere();
+  }
+}
+
+// Test a bit in a register. Result is reflected in CC.
+void MacroAssembler::testbit(Register r, unsigned int bitPos) {
+  if (bitPos < 16) {
+    z_tmll(r, 1U<<bitPos);
+  } else if (bitPos < 32) {
+    z_tmlh(r, 1U<<(bitPos-16));
+  } else if (bitPos < 48) {
+    z_tmhl(r, 1U<<(bitPos-32));
+  } else if (bitPos < 64) {
+    z_tmhh(r, 1U<<(bitPos-48));
+  } else {
+    ShouldNotReachHere();
+  }
+}
+
+// Clear a register, i.e. load const zero into reg.
+// Return len (in bytes) of generated instruction(s).
+// whole_reg: Clear 64 bits if true, 32 bits otherwise.
+// set_cc:    Use instruction that sets the condition code, if true.
+int MacroAssembler::clear_reg(Register r, bool whole_reg, bool set_cc) {
+  unsigned int start_off = offset();
+  if (whole_reg) {
+    set_cc ? z_xgr(r, r) : z_laz(r, 0, Z_R0);
+  } else {  // Only 32bit register.
+    set_cc ? z_xr(r, r) : z_lhi(r, 0);
+  }
+  return offset() - start_off;
+}
+
+#ifdef ASSERT
+int MacroAssembler::preset_reg(Register r, unsigned long pattern, int pattern_len) {
+  switch (pattern_len) {
+    case 1:
+      pattern = (pattern & 0x000000ff)  | ((pattern & 0x000000ff)<<8);
+    case 2:
+      pattern = (pattern & 0x0000ffff)  | ((pattern & 0x0000ffff)<<16);
+    case 4:
+      pattern = (pattern & 0xffffffffL) | ((pattern & 0xffffffffL)<<32);
+    case 8:
+      return load_const_optimized_rtn_len(r, pattern, true);
+      break;
+    default:
+      guarantee(false, "preset_reg: bad len");
+  }
+  return 0;
+}
+#endif
+
+// addr: Address descriptor of memory to clear index register will not be used !
+// size: Number of bytes to clear.
+//    !!! DO NOT USE THEM FOR ATOMIC MEMORY CLEARING !!!
+//    !!! Use store_const() instead                  !!!
+void MacroAssembler::clear_mem(const Address& addr, unsigned size) {
+  guarantee(size <= 256, "MacroAssembler::clear_mem: size too large");
+
+  if (size == 1) {
+    z_mvi(addr, 0);
+    return;
+  }
+
+  switch (size) {
+    case 2: z_mvhhi(addr, 0);
+      return;
+    case 4: z_mvhi(addr, 0);
+      return;
+    case 8: z_mvghi(addr, 0);
+      return;
+    default: ; // Fallthru to xc.
+  }
+
+  z_xc(addr, size, addr);
+}
+
+void MacroAssembler::align(int modulus) {
+  while (offset() % modulus != 0) z_nop();
+}
+
+// Special version for non-relocateable code if required alignment
+// is larger than CodeEntryAlignment.
+void MacroAssembler::align_address(int modulus) {
+  while ((uintptr_t)pc() % modulus != 0) z_nop();
+}
+
+Address MacroAssembler::argument_address(RegisterOrConstant arg_slot,
+                                         Register temp_reg,
+                                         int64_t extra_slot_offset) {
+  // On Z, we can have index and disp in an Address. So don't call argument_offset,
+  // which issues an unnecessary add instruction.
+  int stackElementSize = Interpreter::stackElementSize;
+  int64_t offset = extra_slot_offset * stackElementSize;
+  const Register argbase = Z_esp;
+  if (arg_slot.is_constant()) {
+    offset += arg_slot.as_constant() * stackElementSize;
+    return Address(argbase, offset);
+  }
+  // else
+  assert(temp_reg != noreg, "must specify");
+  assert(temp_reg != Z_ARG1, "base and index are conflicting");
+  z_sllg(temp_reg, arg_slot.as_register(), exact_log2(stackElementSize)); // tempreg = arg_slot << 3
+  return Address(argbase, temp_reg, offset);
+}
+
+
+//===================================================================
+//===   START   C O N S T A N T S   I N   C O D E   S T R E A M   ===
+//===================================================================
+//===            P A T CH A B L E   C O N S T A N T S             ===
+//===================================================================
+
+
+//---------------------------------------------------
+//  Load (patchable) constant into register
+//---------------------------------------------------
+
+
+// Load absolute address (and try to optimize).
+//   Note: This method is usable only for position-fixed code,
+//         referring to a position-fixed target location.
+//         If not so, relocations and patching must be used.
+void MacroAssembler::load_absolute_address(Register d, address addr) {
+  assert(addr != NULL, "should not happen");
+  BLOCK_COMMENT("load_absolute_address:");
+  if (addr == NULL) {
+    z_larl(d, pc()); // Dummy emit for size calc.
+    return;
+  }
+
+  if (RelAddr::is_in_range_of_RelAddr32(addr, pc())) {
+    z_larl(d, addr);
+    return;
+  }
+
+  load_const_optimized(d, (long)addr);
+}
+
+// Load a 64bit constant.
+// Patchable code sequence, but not atomically patchable.
+// Make sure to keep code size constant -> no value-dependent optimizations.
+// Do not kill condition code.
+void MacroAssembler::load_const(Register t, long x) {
+  Assembler::z_iihf(t, (int)(x >> 32));
+  Assembler::z_iilf(t, (int)(x & 0xffffffff));
+}
+
+// Load a 32bit constant into a 64bit register, sign-extend or zero-extend.
+// Patchable code sequence, but not atomically patchable.
+// Make sure to keep code size constant -> no value-dependent optimizations.
+// Do not kill condition code.
+void MacroAssembler::load_const_32to64(Register t, int64_t x, bool sign_extend) {
+  if (sign_extend) { Assembler::z_lgfi(t, x); }
+  else             { Assembler::z_llilf(t, x); }
+}
+
+// Load narrow oop constant, no decompression.
+void MacroAssembler::load_narrow_oop(Register t, narrowOop a) {
+  assert(UseCompressedOops, "must be on to call this method");
+  load_const_32to64(t, a, false /*sign_extend*/);
+}
+
+// Load narrow klass constant, compression required.
+void MacroAssembler::load_narrow_klass(Register t, Klass* k) {
+  assert(UseCompressedClassPointers, "must be on to call this method");
+  narrowKlass encoded_k = Klass::encode_klass(k);
+  load_const_32to64(t, encoded_k, false /*sign_extend*/);
+}
+
+//------------------------------------------------------
+//  Compare (patchable) constant with register.
+//------------------------------------------------------
+
+// Compare narrow oop in reg with narrow oop constant, no decompression.
+void MacroAssembler::compare_immediate_narrow_oop(Register oop1, narrowOop oop2) {
+  assert(UseCompressedOops, "must be on to call this method");
+
+  Assembler::z_clfi(oop1, oop2);
+}
+
+// Compare narrow oop in reg with narrow oop constant, no decompression.
+void MacroAssembler::compare_immediate_narrow_klass(Register klass1, Klass* klass2) {
+  assert(UseCompressedClassPointers, "must be on to call this method");
+  narrowKlass encoded_k = Klass::encode_klass(klass2);
+
+  Assembler::z_clfi(klass1, encoded_k);
+}
+
+//----------------------------------------------------------
+//  Check which kind of load_constant we have here.
+//----------------------------------------------------------
+
+// Detection of CPU version dependent load_const sequence.
+// The detection is valid only for code sequences generated by load_const,
+// not load_const_optimized.
+bool MacroAssembler::is_load_const(address a) {
+  unsigned long inst1, inst2;
+  unsigned int  len1,  len2;
+
+  len1 = get_instruction(a, &inst1);
+  len2 = get_instruction(a + len1, &inst2);
+
+  return is_z_iihf(inst1) && is_z_iilf(inst2);
+}
+
+// Detection of CPU version dependent load_const_32to64 sequence.
+// Mostly used for narrow oops and narrow Klass pointers.
+// The detection is valid only for code sequences generated by load_const_32to64.
+bool MacroAssembler::is_load_const_32to64(address pos) {
+  unsigned long inst1, inst2;
+  unsigned int len1;
+
+  len1 = get_instruction(pos, &inst1);
+  return is_z_llilf(inst1);
+}
+
+// Detection of compare_immediate_narrow sequence.
+// The detection is valid only for code sequences generated by compare_immediate_narrow_oop.
+bool MacroAssembler::is_compare_immediate32(address pos) {
+  return is_equal(pos, CLFI_ZOPC, RIL_MASK);
+}
+
+// Detection of compare_immediate_narrow sequence.
+// The detection is valid only for code sequences generated by compare_immediate_narrow_oop.
+bool MacroAssembler::is_compare_immediate_narrow_oop(address pos) {
+  return is_compare_immediate32(pos);
+  }
+
+// Detection of compare_immediate_narrow sequence.
+// The detection is valid only for code sequences generated by compare_immediate_narrow_klass.
+bool MacroAssembler::is_compare_immediate_narrow_klass(address pos) {
+  return is_compare_immediate32(pos);
+}
+
+//-----------------------------------
+//  patch the load_constant
+//-----------------------------------
+
+// CPU-version dependend patching of load_const.
+void MacroAssembler::patch_const(address a, long x) {
+  assert(is_load_const(a), "not a load of a constant");
+  set_imm32((address)a, (int) ((x >> 32) & 0xffffffff));
+  set_imm32((address)(a + 6), (int)(x & 0xffffffff));
+}
+
+// Patching the value of CPU version dependent load_const_32to64 sequence.
+// The passed ptr MUST be in compressed format!
+int MacroAssembler::patch_load_const_32to64(address pos, int64_t np) {
+  assert(is_load_const_32to64(pos), "not a load of a narrow ptr (oop or klass)");
+
+  set_imm32(pos, np);
+  return 6;
+}
+
+// Patching the value of CPU version dependent compare_immediate_narrow sequence.
+// The passed ptr MUST be in compressed format!
+int MacroAssembler::patch_compare_immediate_32(address pos, int64_t np) {
+  assert(is_compare_immediate32(pos), "not a compressed ptr compare");
+
+  set_imm32(pos, np);
+  return 6;
+}
+
+// Patching the immediate value of CPU version dependent load_narrow_oop sequence.
+// The passed ptr must NOT be in compressed format!
+int MacroAssembler::patch_load_narrow_oop(address pos, oop o) {
+  assert(UseCompressedOops, "Can only patch compressed oops");
+
+  narrowOop no = oopDesc::encode_heap_oop(o);
+  return patch_load_const_32to64(pos, no);
+}
+
+// Patching the immediate value of CPU version dependent load_narrow_klass sequence.
+// The passed ptr must NOT be in compressed format!
+int MacroAssembler::patch_load_narrow_klass(address pos, Klass* k) {
+  assert(UseCompressedClassPointers, "Can only patch compressed klass pointers");
+
+  narrowKlass nk = Klass::encode_klass(k);
+  return patch_load_const_32to64(pos, nk);
+}
+
+// Patching the immediate value of CPU version dependent compare_immediate_narrow_oop sequence.
+// The passed ptr must NOT be in compressed format!
+int MacroAssembler::patch_compare_immediate_narrow_oop(address pos, oop o) {
+  assert(UseCompressedOops, "Can only patch compressed oops");
+
+  narrowOop no = oopDesc::encode_heap_oop(o);
+  return patch_compare_immediate_32(pos, no);
+}
+
+// Patching the immediate value of CPU version dependent compare_immediate_narrow_klass sequence.
+// The passed ptr must NOT be in compressed format!
+int MacroAssembler::patch_compare_immediate_narrow_klass(address pos, Klass* k) {
+  assert(UseCompressedClassPointers, "Can only patch compressed klass pointers");
+
+  narrowKlass nk = Klass::encode_klass(k);
+  return patch_compare_immediate_32(pos, nk);
+}
+
+//------------------------------------------------------------------------
+//  Extract the constant from a load_constant instruction stream.
+//------------------------------------------------------------------------
+
+// Get constant from a load_const sequence.
+long MacroAssembler::get_const(address a) {
+  assert(is_load_const(a), "not a load of a constant");
+  unsigned long x;
+  x =  (((unsigned long) (get_imm32(a,0) & 0xffffffff)) << 32);
+  x |= (((unsigned long) (get_imm32(a,1) & 0xffffffff)));
+  return (long) x;
+}
+
+//--------------------------------------
+//  Store a constant in memory.
+//--------------------------------------
+
+// General emitter to move a constant to memory.
+// The store is atomic.
+//  o Address must be given in RS format (no index register)
+//  o Displacement should be 12bit unsigned for efficiency. 20bit signed also supported.
+//  o Constant can be 1, 2, 4, or 8 bytes, signed or unsigned.
+//  o Memory slot can be 1, 2, 4, or 8 bytes, signed or unsigned.
+//  o Memory slot must be at least as wide as constant, will assert otherwise.
+//  o Signed constants will sign-extend, unsigned constants will zero-extend to slot width.
+int MacroAssembler::store_const(const Address &dest, long imm,
+                                unsigned int lm, unsigned int lc,
+                                Register scratch) {
+  int64_t  disp = dest.disp();
+  Register base = dest.base();
+  assert(!dest.has_index(), "not supported");
+  assert((lm==1)||(lm==2)||(lm==4)||(lm==8), "memory   length not supported");
+  assert((lc==1)||(lc==2)||(lc==4)||(lc==8), "constant length not supported");
+  assert(lm>=lc, "memory slot too small");
+  assert(lc==8 || Immediate::is_simm(imm, lc*8), "const out of range");
+  assert(Displacement::is_validDisp(disp), "displacement out of range");
+
+  bool is_shortDisp = Displacement::is_shortDisp(disp);
+  int store_offset = -1;
+
+  // For target len == 1 it's easy.
+  if (lm == 1) {
+    store_offset = offset();
+    if (is_shortDisp) {
+      z_mvi(disp, base, imm);
+      return store_offset;
+    } else {
+      z_mviy(disp, base, imm);
+      return store_offset;
+    }
+  }
+
+  // All the "good stuff" takes an unsigned displacement.
+  if (is_shortDisp) {
+    // NOTE: Cannot use clear_mem for imm==0, because it is not atomic.
+
+    store_offset = offset();
+    switch (lm) {
+      case 2:  // Lc == 1 handled correctly here, even for unsigned. Instruction does no widening.
+        z_mvhhi(disp, base, imm);
+        return store_offset;
+      case 4:
+        if (Immediate::is_simm16(imm)) {
+          z_mvhi(disp, base, imm);
+          return store_offset;
+        }
+        break;
+      case 8:
+        if (Immediate::is_simm16(imm)) {
+          z_mvghi(disp, base, imm);
+          return store_offset;
+        }
+        break;
+      default:
+        ShouldNotReachHere();
+        break;
+    }
+  }
+
+  //  Can't optimize, so load value and store it.
+  guarantee(scratch != noreg, " need a scratch register here !");
+  if (imm != 0) {
+    load_const_optimized(scratch, imm);  // Preserves CC anyway.
+  } else {
+    // Leave CC alone!!
+    (void) clear_reg(scratch, true, false); // Indicate unused result.
+  }
+
+  store_offset = offset();
+  if (is_shortDisp) {
+    switch (lm) {
+      case 2:
+        z_sth(scratch, disp, Z_R0, base);
+        return store_offset;
+      case 4:
+        z_st(scratch, disp, Z_R0, base);
+        return store_offset;
+      case 8:
+        z_stg(scratch, disp, Z_R0, base);
+        return store_offset;
+      default:
+        ShouldNotReachHere();
+        break;
+    }
+  } else {
+    switch (lm) {
+      case 2:
+        z_sthy(scratch, disp, Z_R0, base);
+        return store_offset;
+      case 4:
+        z_sty(scratch, disp, Z_R0, base);
+        return store_offset;
+      case 8:
+        z_stg(scratch, disp, Z_R0, base);
+        return store_offset;
+      default:
+        ShouldNotReachHere();
+        break;
+    }
+  }
+  return -1; // should not reach here
+}
+
+//===================================================================
+//===       N O T   P A T CH A B L E   C O N S T A N T S          ===
+//===================================================================
+
+// Load constant x into register t with a fast instrcution sequence
+// depending on the bits in x. Preserves CC under all circumstances.
+int MacroAssembler::load_const_optimized_rtn_len(Register t, long x, bool emit) {
+  if (x == 0) {
+    int len;
+    if (emit) {
+      len = clear_reg(t, true, false);
+    } else {
+      len = 4;
+    }
+    return len;
+  }
+
+  if (Immediate::is_simm16(x)) {
+    if (emit) { z_lghi(t, x); }
+    return 4;
+  }
+
+  // 64 bit value: | part1 | part2 | part3 | part4 |
+  // At least one part is not zero!
+  int part1 = ((x >> 32) & 0xffff0000) >> 16;
+  int part2 = (x >> 32) & 0x0000ffff;
+  int part3 = (x & 0xffff0000) >> 16;
+  int part4 = (x & 0x0000ffff);
+
+  // Lower word only (unsigned).
+  if ((part1 == 0) && (part2 == 0)) {
+    if (part3 == 0) {
+      if (emit) z_llill(t, part4);
+      return 4;
+    }
+    if (part4 == 0) {
+      if (emit) z_llilh(t, part3);
+      return 4;
+    }
+    if (emit) z_llilf(t, (int)(x & 0xffffffff));
+    return 6;
+  }
+
+  // Upper word only.
+  if ((part3 == 0) && (part4 == 0)) {
+    if (part1 == 0) {
+      if (emit) z_llihl(t, part2);
+      return 4;
+    }
+    if (part2 == 0) {
+      if (emit) z_llihh(t, part1);
+      return 4;
+    }
+    if (emit) z_llihf(t, (int)(x >> 32));
+    return 6;
+  }
+
+  // Lower word only (signed).
+  if ((part1 == 0x0000ffff) && (part2 == 0x0000ffff) && ((part3 & 0x00008000) != 0)) {
+    if (emit) z_lgfi(t, (int)(x & 0xffffffff));
+    return 6;
+  }
+
+  int len = 0;
+
+  if ((part1 == 0) || (part2 == 0)) {
+    if (part1 == 0) {
+      if (emit) z_llihl(t, part2);
+      len += 4;
+    } else {
+      if (emit) z_llihh(t, part1);
+      len += 4;
+    }
+  } else {
+    if (emit) z_llihf(t, (int)(x >> 32));
+    len += 6;
+  }
+
+  if ((part3 == 0) || (part4 == 0)) {
+    if (part3 == 0) {
+      if (emit) z_iill(t, part4);
+      len += 4;
+    } else {
+      if (emit) z_iilh(t, part3);
+      len += 4;
+    }
+  } else {
+    if (emit) z_iilf(t, (int)(x & 0xffffffff));
+    len += 6;
+  }
+  return len;
+}
+
+//=====================================================================
+//===     H I G H E R   L E V E L   B R A N C H   E M I T T E R S   ===
+//=====================================================================
+
+// Note: In the worst case, one of the scratch registers is destroyed!!!
+void MacroAssembler::compare32_and_branch(Register r1, RegisterOrConstant x2, branch_condition cond, Label& lbl) {
+  // Right operand is constant.
+  if (x2.is_constant()) {
+    jlong value = x2.as_constant();
+    compare_and_branch_optimized(r1, value, cond, lbl, /*len64=*/false, /*has_sign=*/true);
+    return;
+  }
+
+  // Right operand is in register.
+  compare_and_branch_optimized(r1, x2.as_register(), cond, lbl, /*len64=*/false, /*has_sign=*/true);
+}
+
+// Note: In the worst case, one of the scratch registers is destroyed!!!
+void MacroAssembler::compareU32_and_branch(Register r1, RegisterOrConstant x2, branch_condition cond, Label& lbl) {
+  // Right operand is constant.
+  if (x2.is_constant()) {
+    jlong value = x2.as_constant();
+    compare_and_branch_optimized(r1, value, cond, lbl, /*len64=*/false, /*has_sign=*/false);
+    return;
+  }
+
+  // Right operand is in register.
+  compare_and_branch_optimized(r1, x2.as_register(), cond, lbl, /*len64=*/false, /*has_sign=*/false);
+}
+
+// Note: In the worst case, one of the scratch registers is destroyed!!!
+void MacroAssembler::compare64_and_branch(Register r1, RegisterOrConstant x2, branch_condition cond, Label& lbl) {
+  // Right operand is constant.
+  if (x2.is_constant()) {
+    jlong value = x2.as_constant();
+    compare_and_branch_optimized(r1, value, cond, lbl, /*len64=*/true, /*has_sign=*/true);
+    return;
+  }
+
+  // Right operand is in register.
+  compare_and_branch_optimized(r1, x2.as_register(), cond, lbl, /*len64=*/true, /*has_sign=*/true);
+}
+
+void MacroAssembler::compareU64_and_branch(Register r1, RegisterOrConstant x2, branch_condition cond, Label& lbl) {
+  // Right operand is constant.
+  if (x2.is_constant()) {
+    jlong value = x2.as_constant();
+    compare_and_branch_optimized(r1, value, cond, lbl, /*len64=*/true, /*has_sign=*/false);
+    return;
+  }
+
+  // Right operand is in register.
+  compare_and_branch_optimized(r1, x2.as_register(), cond, lbl, /*len64=*/true, /*has_sign=*/false);
+}
+
+// Generate an optimal branch to the branch target.
+// Optimal means that a relative branch (brc or brcl) is used if the
+// branch distance is short enough. Loading the target address into a
+// register and branching via reg is used as fallback only.
+//
+// Used registers:
+//   Z_R1 - work reg. Holds branch target address.
+//          Used in fallback case only.
+//
+// This version of branch_optimized is good for cases where the target address is known
+// and constant, i.e. is never changed (no relocation, no patching).
+void MacroAssembler::branch_optimized(Assembler::branch_condition cond, address branch_addr) {
+  address branch_origin = pc();
+
+  if (RelAddr::is_in_range_of_RelAddr16(branch_addr, branch_origin)) {
+    z_brc(cond, branch_addr);
+  } else if (RelAddr::is_in_range_of_RelAddr32(branch_addr, branch_origin)) {
+    z_brcl(cond, branch_addr);
+  } else {
+    load_const_optimized(Z_R1, branch_addr);  // CC must not get killed by load_const_optimized.
+    z_bcr(cond, Z_R1);
+  }
+}
+
+// This version of branch_optimized is good for cases where the target address
+// is potentially not yet known at the time the code is emitted.
+//
+// One very common case is a branch to an unbound label which is handled here.
+// The caller might know (or hope) that the branch distance is short enough
+// to be encoded in a 16bit relative address. In this case he will pass a
+// NearLabel branch_target.
+// Care must be taken with unbound labels. Each call to target(label) creates
+// an entry in the patch queue for that label to patch all references of the label
+// once it gets bound. Those recorded patch locations must be patchable. Otherwise,
+// an assertion fires at patch time.
+void MacroAssembler::branch_optimized(Assembler::branch_condition cond, Label& branch_target) {
+  if (branch_target.is_bound()) {
+    address branch_addr = target(branch_target);
+    branch_optimized(cond, branch_addr);
+  } else {
+    z_brcl(cond, branch_target); // Let's hope target is in range. Otherwise, we will abort at patch time.
+  }
+}
+
+// Generate an optimal compare and branch to the branch target.
+// Optimal means that a relative branch (clgrj, brc or brcl) is used if the
+// branch distance is short enough. Loading the target address into a
+// register and branching via reg is used as fallback only.
+//
+// Input:
+//   r1 - left compare operand
+//   r2 - right compare operand
+void MacroAssembler::compare_and_branch_optimized(Register r1,
+                                                  Register r2,
+                                                  Assembler::branch_condition cond,
+                                                  address  branch_addr,
+                                                  bool     len64,
+                                                  bool     has_sign) {
+  unsigned int casenum = (len64?2:0)+(has_sign?0:1);
+
+  address branch_origin = pc();
+  if (VM_Version::has_CompareBranch() && RelAddr::is_in_range_of_RelAddr16(branch_addr, branch_origin)) {
+    switch (casenum) {
+      case 0: z_crj( r1, r2, cond, branch_addr); break;
+      case 1: z_clrj (r1, r2, cond, branch_addr); break;
+      case 2: z_cgrj(r1, r2, cond, branch_addr); break;
+      case 3: z_clgrj(r1, r2, cond, branch_addr); break;
+      default: ShouldNotReachHere(); break;
+    }
+  } else {
+    switch (casenum) {
+      case 0: z_cr( r1, r2); break;
+      case 1: z_clr(r1, r2); break;
+      case 2: z_cgr(r1, r2); break;
+      case 3: z_clgr(r1, r2); break;
+      default: ShouldNotReachHere(); break;
+    }
+    branch_optimized(cond, branch_addr);
+  }
+}
+
+// Generate an optimal compare and branch to the branch target.
+// Optimal means that a relative branch (clgij, brc or brcl) is used if the
+// branch distance is short enough. Loading the target address into a
+// register and branching via reg is used as fallback only.
+//
+// Input:
+//   r1 - left compare operand (in register)
+//   x2 - right compare operand (immediate)
+void MacroAssembler::compare_and_branch_optimized(Register r1,
+                                                  jlong    x2,
+                                                  Assembler::branch_condition cond,
+                                                  Label&   branch_target,
+                                                  bool     len64,
+                                                  bool     has_sign) {
+  address      branch_origin = pc();
+  bool         x2_imm8       = (has_sign && Immediate::is_simm8(x2)) || (!has_sign && Immediate::is_uimm8(x2));
+  bool         is_RelAddr16  = (branch_target.is_bound() &&
+                                RelAddr::is_in_range_of_RelAddr16(target(branch_target), branch_origin));
+  unsigned int casenum       = (len64?2:0)+(has_sign?0:1);
+
+  if (VM_Version::has_CompareBranch() && is_RelAddr16 && x2_imm8) {
+    switch (casenum) {
+      case 0: z_cij( r1, x2, cond, branch_target); break;
+      case 1: z_clij(r1, x2, cond, branch_target); break;
+      case 2: z_cgij(r1, x2, cond, branch_target); break;
+      case 3: z_clgij(r1, x2, cond, branch_target); break;
+      default: ShouldNotReachHere(); break;
+    }
+    return;
+  }
+
+  if (x2 == 0) {
+    switch (casenum) {
+      case 0: z_ltr(r1, r1); break;
+      case 1: z_ltr(r1, r1); break; // Caution: unsigned test only provides zero/notZero indication!
+      case 2: z_ltgr(r1, r1); break;
+      case 3: z_ltgr(r1, r1); break; // Caution: unsigned test only provides zero/notZero indication!
+      default: ShouldNotReachHere(); break;
+    }
+  } else {
+    if ((has_sign && Immediate::is_simm16(x2)) || (!has_sign && Immediate::is_uimm(x2, 15))) {
+      switch (casenum) {
+        case 0: z_chi(r1, x2); break;
+        case 1: z_chi(r1, x2); break; // positive immediate < 2**15
+        case 2: z_cghi(r1, x2); break;
+        case 3: z_cghi(r1, x2); break; // positive immediate < 2**15
+        default: break;
+      }
+    } else if ( (has_sign && Immediate::is_simm32(x2)) || (!has_sign && Immediate::is_uimm32(x2)) ) {
+      switch (casenum) {
+        case 0: z_cfi( r1, x2); break;
+        case 1: z_clfi(r1, x2); break;
+        case 2: z_cgfi(r1, x2); break;
+        case 3: z_clgfi(r1, x2); break;
+        default: ShouldNotReachHere(); break;
+      }
+    } else {
+      // No instruction with immediate operand possible, so load into register.
+      Register scratch = (r1 != Z_R0) ? Z_R0 : Z_R1;
+      load_const_optimized(scratch, x2);
+      switch (casenum) {
+        case 0: z_cr( r1, scratch); break;
+        case 1: z_clr(r1, scratch); break;
+        case 2: z_cgr(r1, scratch); break;
+        case 3: z_clgr(r1, scratch); break;
+        default: ShouldNotReachHere(); break;
+      }
+    }
+  }
+  branch_optimized(cond, branch_target);
+}
+
+// Generate an optimal compare and branch to the branch target.
+// Optimal means that a relative branch (clgrj, brc or brcl) is used if the
+// branch distance is short enough. Loading the target address into a
+// register and branching via reg is used as fallback only.
+//
+// Input:
+//   r1 - left compare operand
+//   r2 - right compare operand
+void MacroAssembler::compare_and_branch_optimized(Register r1,
+                                                  Register r2,
+                                                  Assembler::branch_condition cond,
+                                                  Label&   branch_target,
+                                                  bool     len64,
+                                                  bool     has_sign) {
+  unsigned int casenum = (len64?2:0)+(has_sign?0:1);
+
+  if (branch_target.is_bound()) {
+    address branch_addr = target(branch_target);
+    compare_and_branch_optimized(r1, r2, cond, branch_addr, len64, has_sign);
+  } else {
+    {
+      switch (casenum) {
+        case 0: z_cr( r1, r2); break;
+        case 1: z_clr(r1, r2); break;
+        case 2: z_cgr(r1, r2); break;
+        case 3: z_clgr(r1, r2); break;
+        default: ShouldNotReachHere(); break;
+      }
+      branch_optimized(cond, branch_target);
+    }
+  }
+}
+
+//===========================================================================
+//===   END     H I G H E R   L E V E L   B R A N C H   E M I T T E R S   ===
+//===========================================================================
+
+AddressLiteral MacroAssembler::allocate_metadata_address(Metadata* obj) {
+  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  int index = oop_recorder()->allocate_metadata_index(obj);
+  RelocationHolder rspec = metadata_Relocation::spec(index);
+  return AddressLiteral((address)obj, rspec);
+}
+
+AddressLiteral MacroAssembler::constant_metadata_address(Metadata* obj) {
+  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  int index = oop_recorder()->find_index(obj);
+  RelocationHolder rspec = metadata_Relocation::spec(index);
+  return AddressLiteral((address)obj, rspec);
+}
+
+AddressLiteral MacroAssembler::allocate_oop_address(jobject obj) {
+  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  int oop_index = oop_recorder()->allocate_oop_index(obj);
+  return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
+}
+
+AddressLiteral MacroAssembler::constant_oop_address(jobject obj) {
+  assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
+  int oop_index = oop_recorder()->find_index(obj);
+  return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
+}
+
+// NOTE: destroys r
+void MacroAssembler::c2bool(Register r, Register t) {
+  z_lcr(t, r);   // t = -r
+  z_or(r, t);    // r = -r OR r
+  z_srl(r, 31);  // Yields 0 if r was 0, 1 otherwise.
+}
+
+RegisterOrConstant MacroAssembler::delayed_value_impl(intptr_t* delayed_value_addr,
+                                                      Register tmp,
+                                                      int offset) {
+  intptr_t value = *delayed_value_addr;
+  if (value != 0) {
+    return RegisterOrConstant(value + offset);
+  }
+
+  BLOCK_COMMENT("delayed_value {");
+  // Load indirectly to solve generation ordering problem.
+  load_absolute_address(tmp, (address) delayed_value_addr); // tmp = a;
+  z_lg(tmp, 0, tmp);                   // tmp = *tmp;
+
+#ifdef ASSERT
+  NearLabel L;
+  compare64_and_branch(tmp, (intptr_t)0L, Assembler::bcondNotEqual, L);
+  z_illtrap();
+  bind(L);
+#endif
+
+  if (offset != 0) {
+    z_agfi(tmp, offset);               // tmp = tmp + offset;
+  }
+
+  BLOCK_COMMENT("} delayed_value");
+  return RegisterOrConstant(tmp);
+}
+
+// Patch instruction `inst' at offset `inst_pos' to refer to `dest_pos'
+// and return the resulting instruction.
+// Dest_pos and inst_pos are 32 bit only. These parms can only designate
+// relative positions.
+// Use correct argument types. Do not pre-calculate distance.
+unsigned long MacroAssembler::patched_branch(address dest_pos, unsigned long inst, address inst_pos) {
+  int c = 0;
+  unsigned long patched_inst = 0;
+  if (is_call_pcrelative_short(inst) ||
+      is_branch_pcrelative_short(inst) ||
+      is_branchoncount_pcrelative_short(inst) ||
+      is_branchonindex32_pcrelative_short(inst)) {
+    c = 1;
+    int m = fmask(15, 0);    // simm16(-1, 16, 32);
+    int v = simm16(RelAddr::pcrel_off16(dest_pos, inst_pos), 16, 32);
+    patched_inst = (inst & ~m) | v;
+  } else if (is_compareandbranch_pcrelative_short(inst)) {
+    c = 2;
+    long m = fmask(31, 16);  // simm16(-1, 16, 48);
+    long v = simm16(RelAddr::pcrel_off16(dest_pos, inst_pos), 16, 48);
+    patched_inst = (inst & ~m) | v;
+  } else if (is_branchonindex64_pcrelative_short(inst)) {
+    c = 3;
+    long m = fmask(31, 16);  // simm16(-1, 16, 48);
+    long v = simm16(RelAddr::pcrel_off16(dest_pos, inst_pos), 16, 48);
+    patched_inst = (inst & ~m) | v;
+  } else if (is_call_pcrelative_long(inst) || is_branch_pcrelative_long(inst)) {
+    c = 4;
+    long m = fmask(31, 0);  // simm32(-1, 16, 48);
+    long v = simm32(RelAddr::pcrel_off32(dest_pos, inst_pos), 16, 48);
+    patched_inst = (inst & ~m) | v;
+  } else if (is_pcrelative_long(inst)) { // These are the non-branch pc-relative instructions.
+    c = 5;
+    long m = fmask(31, 0);  // simm32(-1, 16, 48);
+    long v = simm32(RelAddr::pcrel_off32(dest_pos, inst_pos), 16, 48);
+    patched_inst = (inst & ~m) | v;
+  } else {
+    print_dbg_msg(tty, inst, "not a relative branch", 0);
+    dump_code_range(tty, inst_pos, 32, "not a pcrelative branch");
+    ShouldNotReachHere();
+  }
+
+  long new_off = get_pcrel_offset(patched_inst);
+  if (new_off != (dest_pos-inst_pos)) {
+    tty->print_cr("case %d: dest_pos = %p, inst_pos = %p, disp = %ld(%12.12lx)", c, dest_pos, inst_pos, new_off, new_off);
+    print_dbg_msg(tty, inst,         "<- original instruction: branch patching error", 0);
+    print_dbg_msg(tty, patched_inst, "<- patched  instruction: branch patching error", 0);
+#ifdef LUCY_DBG
+    VM_Version::z_SIGSEGV();
+#endif
+    ShouldNotReachHere();
+  }
+  return patched_inst;
+}
+
+// Only called when binding labels (share/vm/asm/assembler.cpp)
+// Pass arguments as intended. Do not pre-calculate distance.
+void MacroAssembler::pd_patch_instruction(address branch, address target) {
+  unsigned long stub_inst;
+  int           inst_len = get_instruction(branch, &stub_inst);
+
+  set_instruction(branch, patched_branch(target, stub_inst, branch), inst_len);
+}
+
+
+// Extract relative address (aka offset).
+// inv_simm16 works for 4-byte instructions only.
+// compare and branch instructions are 6-byte and have a 16bit offset "in the middle".
+long MacroAssembler::get_pcrel_offset(unsigned long inst) {
+
+  if (MacroAssembler::is_pcrelative_short(inst)) {
+    if (((inst&0xFFFFffff00000000UL) == 0) && ((inst&0x00000000FFFF0000UL) != 0)) {
+      return RelAddr::inv_pcrel_off16(inv_simm16(inst));
+    } else {
+      return RelAddr::inv_pcrel_off16(inv_simm16_48(inst));
+    }
+  }
+
+  if (MacroAssembler::is_pcrelative_long(inst)) {
+    return RelAddr::inv_pcrel_off32(inv_simm32(inst));
+  }
+
+  print_dbg_msg(tty, inst, "not a pcrelative instruction", 6);
+#ifdef LUCY_DBG
+  VM_Version::z_SIGSEGV();
+#else
+  ShouldNotReachHere();
+#endif
+  return -1;
+}
+
+long MacroAssembler::get_pcrel_offset(address pc) {
+  unsigned long inst;
+  unsigned int  len = get_instruction(pc, &inst);
+
+#ifdef ASSERT
+  long offset;
+  if (MacroAssembler::is_pcrelative_short(inst) || MacroAssembler::is_pcrelative_long(inst)) {
+    offset = get_pcrel_offset(inst);
+  } else {
+    offset = -1;
+  }
+
+  if (offset == -1) {
+    dump_code_range(tty, pc, 32, "not a pcrelative instruction");
+#ifdef LUCY_DBG
+    VM_Version::z_SIGSEGV();
+#else
+    ShouldNotReachHere();
+#endif
+  }
+  return offset;
+#else
+  return get_pcrel_offset(inst);
+#endif // ASSERT
+}
+
+// Get target address from pc-relative instructions.
+address MacroAssembler::get_target_addr_pcrel(address pc) {
+  assert(is_pcrelative_long(pc), "not a pcrelative instruction");
+  return pc + get_pcrel_offset(pc);
+}
+
+// Patch pc relative load address.
+void MacroAssembler::patch_target_addr_pcrel(address pc, address con) {
+  unsigned long inst;
+  // Offset is +/- 2**32 -> use long.
+  ptrdiff_t distance = con - pc;
+
+  get_instruction(pc, &inst);
+
+  if (is_pcrelative_short(inst)) {
+    *(short *)(pc+2) = RelAddr::pcrel_off16(con, pc);  // Instructions are at least 2-byte aligned, no test required.
+
+    // Some extra safety net.
+    if (!RelAddr::is_in_range_of_RelAddr16(distance)) {
+      print_dbg_msg(tty, inst, "distance out of range (16bit)", 4);
+      dump_code_range(tty, pc, 32, "distance out of range (16bit)");
+      guarantee(RelAddr::is_in_range_of_RelAddr16(distance), "too far away (more than +/- 2**16");
+    }
+    return;
+  }
+
+  if (is_pcrelative_long(inst)) {
+    *(int *)(pc+2)   = RelAddr::pcrel_off32(con, pc);
+
+    // Some Extra safety net.
+    if (!RelAddr::is_in_range_of_RelAddr32(distance)) {
+      print_dbg_msg(tty, inst, "distance out of range (32bit)", 6);
+      dump_code_range(tty, pc, 32, "distance out of range (32bit)");
+      guarantee(RelAddr::is_in_range_of_RelAddr32(distance), "too far away (more than +/- 2**32");
+    }
+    return;
+  }
+
+  guarantee(false, "not a pcrelative instruction to patch!");
+}
+
+// "Current PC" here means the address just behind the basr instruction.
+address MacroAssembler::get_PC(Register result) {
+  z_basr(result, Z_R0); // Don't branch, just save next instruction address in result.
+  return pc();
+}
+
+// Get current PC + offset.
+// Offset given in bytes, must be even!
+// "Current PC" here means the address of the larl instruction plus the given offset.
+address MacroAssembler::get_PC(Register result, int64_t offset) {
+  address here = pc();
+  z_larl(result, offset/2); // Save target instruction address in result.
+  return here + offset;
+}
+
+// Resize_frame with SP(new) = SP(old) - [offset].
+void MacroAssembler::resize_frame_sub(Register offset, Register fp, bool load_fp)
+{
+  assert_different_registers(offset, fp, Z_SP);
+  if (load_fp) { z_lg(fp, _z_abi(callers_sp), Z_SP); }
+
+  z_sgr(Z_SP, offset);
+  z_stg(fp, _z_abi(callers_sp), Z_SP);
+}
+
+// Resize_frame with SP(new) = [addr].
+void MacroAssembler::resize_frame_absolute(Register addr, Register fp, bool load_fp) {
+  assert_different_registers(addr, fp, Z_SP);
+  if (load_fp) { z_lg(fp, _z_abi(callers_sp), Z_SP); }
+
+  if (addr != Z_R0) {
+    // Minimize stalls by not using Z_SP immediately after update.
+    z_stg(fp, _z_abi(callers_sp), addr);
+    z_lgr(Z_SP, addr);
+  } else {
+    z_lgr(Z_SP, addr);
+    z_stg(fp, _z_abi(callers_sp), Z_SP);
+  }
+}
+
+// Resize_frame with SP(new) = SP(old) + offset.
+void MacroAssembler::resize_frame(RegisterOrConstant offset, Register fp, bool load_fp) {
+  assert_different_registers(fp, Z_SP);
+  if (load_fp) z_lg(fp, _z_abi(callers_sp), Z_SP);
+
+  if (Displacement::is_validDisp((int)_z_abi(callers_sp) + offset.constant_or_zero())) {
+    // Minimize stalls by first using, then updating Z_SP.
+    // Do that only if we have a small positive offset or if ExtImm are available.
+    z_stg(fp, Address(Z_SP, offset, _z_abi(callers_sp)));
+    add64(Z_SP, offset);
+  } else {
+    add64(Z_SP, offset);
+    z_stg(fp, _z_abi(callers_sp), Z_SP);
+  }
+}
+
+void MacroAssembler::push_frame(Register bytes, Register old_sp, bool copy_sp, bool bytes_with_inverted_sign) {
+#ifdef ASSERT
+  assert_different_registers(bytes, old_sp, Z_SP);
+  if (!copy_sp) {
+    z_cgr(old_sp, Z_SP);
+    asm_assert_eq("[old_sp]!=[Z_SP]", 0x211);
+  }
+#endif
+  if (copy_sp) { z_lgr(old_sp, Z_SP); }
+  if (bytes_with_inverted_sign) {
+    z_stg(old_sp, 0, bytes, Z_SP);
+    add2reg_with_index(Z_SP, 0, bytes, Z_SP);
+  } else {
+    z_sgr(Z_SP, bytes); // Z_sgfr sufficient, but probably not faster.
+    z_stg(old_sp, 0, Z_SP);
+  }
+}
+
+unsigned int MacroAssembler::push_frame(unsigned int bytes, Register scratch) {
+  long offset = Assembler::align(bytes, frame::alignment_in_bytes);
+
+  if (Displacement::is_validDisp(-offset)) {
+    // Minimize stalls by first using, then updating Z_SP.
+    // Do that only if we have ExtImm available.
+    z_stg(Z_SP, -offset, Z_SP);
+    add2reg(Z_SP, -offset);
+  } else {
+    if (scratch != Z_R0 && scratch != Z_R1) {
+      z_stg(Z_SP, -offset, Z_SP);
+      add2reg(Z_SP, -offset);
+    } else {   // scratch == Z_R0 || scratch == Z_R1
+      z_lgr(scratch, Z_SP);
+      add2reg(Z_SP, -offset);
+      z_stg(scratch, 0, Z_SP);
+    }
+  }
+  return offset;
+}
+
+// Push a frame of size `bytes' plus abi160 on top.
+unsigned int MacroAssembler::push_frame_abi160(unsigned int bytes) {
+  BLOCK_COMMENT("push_frame_abi160 {");
+  unsigned int res = push_frame(bytes + frame::z_abi_160_size);
+  BLOCK_COMMENT("} push_frame_abi160");
+  return res;
+}
+
+// Pop current C frame.
+void MacroAssembler::pop_frame() {
+  BLOCK_COMMENT("pop_frame:");
+  Assembler::z_lg(Z_SP, _z_abi(callers_sp), Z_SP);
+}
+
+void MacroAssembler::call_VM_leaf_base(address entry_point, bool allow_relocation) {
+  if (allow_relocation) {
+    call_c(entry_point);
+  } else {
+    call_c_static(entry_point);
+  }
+}
+
+void MacroAssembler::call_VM_leaf_base(address entry_point) {
+  bool allow_relocation = true;
+  call_VM_leaf_base(entry_point, allow_relocation);
+}
+
+void MacroAssembler::call_VM_base(Register oop_result,
+                                  Register last_java_sp,
+                                  address  entry_point,
+                                  bool     allow_relocation,
+                                  bool     check_exceptions) { // Defaults to true.
+  // Allow_relocation indicates, if true, that the generated code shall
+  // be fit for code relocation or referenced data relocation. In other
+  // words: all addresses must be considered variable. PC-relative addressing
+  // is not possible then.
+  // On the other hand, if (allow_relocation == false), addresses and offsets
+  // may be considered stable, enabling us to take advantage of some PC-relative
+  // addressing tweaks. These might improve performance and reduce code size.
+
+  // Determine last_java_sp register.
+  if (!last_java_sp->is_valid()) {
+    last_java_sp = Z_SP;  // Load Z_SP as SP.
+  }
+
+  set_top_ijava_frame_at_SP_as_last_Java_frame(last_java_sp, Z_R1, allow_relocation);
+
+  // ARG1 must hold thread address.
+  z_lgr(Z_ARG1, Z_thread);
+
+  address return_pc = NULL;
+  if (allow_relocation) {
+    return_pc = call_c(entry_point);
+  } else {
+    return_pc = call_c_static(entry_point);
+  }
+
+  reset_last_Java_frame(allow_relocation);
+
+  // C++ interp handles this in the interpreter.
+  check_and_handle_popframe(Z_thread);
+  check_and_handle_earlyret(Z_thread);
+
+  // Check for pending exceptions.
+  if (check_exceptions) {
+    // Check for pending exceptions (java_thread is set upon return).
+    load_and_test_long(Z_R0_scratch, Address(Z_thread, Thread::pending_exception_offset()));
+
+    // This used to conditionally jump to forward_exception however it is
+    // possible if we relocate that the branch will not reach. So we must jump
+    // around so we can always reach.
+
+    Label ok;
+    z_bre(ok); // Bcondequal is the same as bcondZero.
+    call_stub(StubRoutines::forward_exception_entry());
+    bind(ok);
+  }
+
+  // Get oop result if there is one and reset the value in the thread.
+  if (oop_result->is_valid()) {
+    get_vm_result(oop_result);
+  }
+
+  _last_calls_return_pc = return_pc;  // Wipe out other (error handling) calls.
+}
+
+void MacroAssembler::call_VM_base(Register oop_result,
+                                  Register last_java_sp,
+                                  address  entry_point,
+                                  bool     check_exceptions) { // Defaults to true.
+  bool allow_relocation = true;
+  call_VM_base(oop_result, last_java_sp, entry_point, allow_relocation, check_exceptions);
+}
+
+// VM calls without explicit last_java_sp.
+
+void MacroAssembler::call_VM(Register oop_result, address entry_point, bool check_exceptions) {
+  // Call takes possible detour via InterpreterMacroAssembler.
+  call_VM_base(oop_result, noreg, entry_point, true, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, bool check_exceptions) {
+  // Z_ARG1 is reserved for the thread.
+  lgr_if_needed(Z_ARG2, arg_1);
+  call_VM(oop_result, entry_point, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2, bool check_exceptions) {
+  // Z_ARG1 is reserved for the thread.
+  lgr_if_needed(Z_ARG2, arg_1);
+  assert(arg_2 != Z_ARG2, "smashed argument");
+  lgr_if_needed(Z_ARG3, arg_2);
+  call_VM(oop_result, entry_point, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2,
+                             Register arg_3, bool check_exceptions) {
+  // Z_ARG1 is reserved for the thread.
+  lgr_if_needed(Z_ARG2, arg_1);
+  assert(arg_2 != Z_ARG2, "smashed argument");
+  lgr_if_needed(Z_ARG3, arg_2);
+  assert(arg_3 != Z_ARG2 && arg_3 != Z_ARG3, "smashed argument");
+  lgr_if_needed(Z_ARG4, arg_3);
+  call_VM(oop_result, entry_point, check_exceptions);
+}
+
+// VM static calls without explicit last_java_sp.
+
+void MacroAssembler::call_VM_static(Register oop_result, address entry_point, bool check_exceptions) {
+  // Call takes possible detour via InterpreterMacroAssembler.
+  call_VM_base(oop_result, noreg, entry_point, false, check_exceptions);
+}
+
+void MacroAssembler::call_VM_static(Register oop_result, address entry_point, Register arg_1, Register arg_2,
+                                    Register arg_3, bool check_exceptions) {
+  // Z_ARG1 is reserved for the thread.
+  lgr_if_needed(Z_ARG2, arg_1);
+  assert(arg_2 != Z_ARG2, "smashed argument");
+  lgr_if_needed(Z_ARG3, arg_2);
+  assert(arg_3 != Z_ARG2 && arg_3 != Z_ARG3, "smashed argument");
+  lgr_if_needed(Z_ARG4, arg_3);
+  call_VM_static(oop_result, entry_point, check_exceptions);
+}
+
+// VM calls with explicit last_java_sp.
+
+void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, bool check_exceptions) {
+  // Call takes possible detour via InterpreterMacroAssembler.
+  call_VM_base(oop_result, last_java_sp, entry_point, true, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1, bool check_exceptions) {
+   // Z_ARG1 is reserved for the thread.
+   lgr_if_needed(Z_ARG2, arg_1);
+   call_VM(oop_result, last_java_sp, entry_point, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1,
+                             Register arg_2, bool check_exceptions) {
+   // Z_ARG1 is reserved for the thread.
+   lgr_if_needed(Z_ARG2, arg_1);
+   assert(arg_2 != Z_ARG2, "smashed argument");
+   lgr_if_needed(Z_ARG3, arg_2);
+   call_VM(oop_result, last_java_sp, entry_point, check_exceptions);
+}
+
+void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1,
+                             Register arg_2, Register arg_3, bool check_exceptions) {
+  // Z_ARG1 is reserved for the thread.
+  lgr_if_needed(Z_ARG2, arg_1);
+  assert(arg_2 != Z_ARG2, "smashed argument");
+  lgr_if_needed(Z_ARG3, arg_2);
+  assert(arg_3 != Z_ARG2 && arg_3 != Z_ARG3, "smashed argument");
+  lgr_if_needed(Z_ARG4, arg_3);
+  call_VM(oop_result, last_java_sp, entry_point, check_exceptions);
+}
+
+// VM leaf calls.
+
+void MacroAssembler::call_VM_leaf(address entry_point) {
+  // Call takes possible detour via InterpreterMacroAssembler.
+  call_VM_leaf_base(entry_point, true);
+}
+
+void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  call_VM_leaf(entry_point);
+}
+
+void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  assert(arg_2 != Z_ARG1, "smashed argument");
+  if (arg_2 != noreg) lgr_if_needed(Z_ARG2, arg_2);
+  call_VM_leaf(entry_point);
+}
+
+void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2, Register arg_3) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  assert(arg_2 != Z_ARG1, "smashed argument");
+  if (arg_2 != noreg) lgr_if_needed(Z_ARG2, arg_2);
+  assert(arg_3 != Z_ARG1 && arg_3 != Z_ARG2, "smashed argument");
+  if (arg_3 != noreg) lgr_if_needed(Z_ARG3, arg_3);
+  call_VM_leaf(entry_point);
+}
+
+// Static VM leaf calls.
+// Really static VM leaf calls are never patched.
+
+void MacroAssembler::call_VM_leaf_static(address entry_point) {
+  // Call takes possible detour via InterpreterMacroAssembler.
+  call_VM_leaf_base(entry_point, false);
+}
+
+void MacroAssembler::call_VM_leaf_static(address entry_point, Register arg_1) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  call_VM_leaf_static(entry_point);
+}
+
+void MacroAssembler::call_VM_leaf_static(address entry_point, Register arg_1, Register arg_2) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  assert(arg_2 != Z_ARG1, "smashed argument");
+  if (arg_2 != noreg) lgr_if_needed(Z_ARG2, arg_2);
+  call_VM_leaf_static(entry_point);
+}
+
+void MacroAssembler::call_VM_leaf_static(address entry_point, Register arg_1, Register arg_2, Register arg_3) {
+  if (arg_1 != noreg) lgr_if_needed(Z_ARG1, arg_1);
+  assert(arg_2 != Z_ARG1, "smashed argument");
+  if (arg_2 != noreg) lgr_if_needed(Z_ARG2, arg_2);
+  assert(arg_3 != Z_ARG1 && arg_3 != Z_ARG2, "smashed argument");
+  if (arg_3 != noreg) lgr_if_needed(Z_ARG3, arg_3);
+  call_VM_leaf_static(entry_point);
+}
+
+// Don't use detour via call_c(reg).
+address MacroAssembler::call_c(address function_entry) {
+  load_const(Z_R1, function_entry);
+  return call(Z_R1);
+}
+
+// Variant for really static (non-relocatable) calls which are never patched.
+address MacroAssembler::call_c_static(address function_entry) {
+  load_absolute_address(Z_R1, function_entry);
+#if 0 // def ASSERT
+  // Verify that call site did not move.
+  load_const_optimized(Z_R0, function_entry);
+  z_cgr(Z_R1, Z_R0);
+  z_brc(bcondEqual, 3);
+  z_illtrap(0xba);
+#endif
+  return call(Z_R1);
+}
+
+address MacroAssembler::call_c_opt(address function_entry) {
+  bool success = call_far_patchable(function_entry, -2 /* emit relocation + constant */);
+  _last_calls_return_pc = success ? pc() : NULL;
+  return _last_calls_return_pc;
+}
+
+// Identify a call_far_patchable instruction: LARL + LG + BASR
+//
+//    nop                   ; optionally, if required for alignment
+//    lgrl rx,A(TOC entry)  ; PC-relative access into constant pool
+//    basr Z_R14,rx         ; end of this instruction must be aligned to a word boundary
+//
+// Code pattern will eventually get patched into variant2 (see below for detection code).
+//
+bool MacroAssembler::is_call_far_patchable_variant0_at(address instruction_addr) {
+  address iaddr = instruction_addr;
+
+  // Check for the actual load instruction.
+  if (!is_load_const_from_toc(iaddr)) { return false; }
+  iaddr += load_const_from_toc_size();
+
+  // Check for the call (BASR) instruction, finally.
+  assert(iaddr-instruction_addr+call_byregister_size() == call_far_patchable_size(), "size mismatch");
+  return is_call_byregister(iaddr);
+}
+
+// Identify a call_far_patchable instruction: BRASL
+//
+// Code pattern to suits atomic patching:
+//    nop                       ; Optionally, if required for alignment.
+//    nop    ...                ; Multiple filler nops to compensate for size difference (variant0 is longer).
+//    nop                       ; For code pattern detection: Prepend each BRASL with a nop.
+//    brasl  Z_R14,<reladdr>    ; End of code must be 4-byte aligned !
+bool MacroAssembler::is_call_far_patchable_variant2_at(address instruction_addr) {
+  const address call_addr = (address)((intptr_t)instruction_addr + call_far_patchable_size() - call_far_pcrelative_size());
+
+  // Check for correct number of leading nops.
+  address iaddr;
+  for (iaddr = instruction_addr; iaddr < call_addr; iaddr += nop_size()) {
+    if (!is_z_nop(iaddr)) { return false; }
+  }
+  assert(iaddr == call_addr, "sanity");
+
+  // --> Check for call instruction.
+  if (is_call_far_pcrelative(call_addr)) {
+    assert(call_addr-instruction_addr+call_far_pcrelative_size() == call_far_patchable_size(), "size mismatch");
+    return true;
+  }
+
+  return false;
+}
+
+// Emit a NOT mt-safely patchable 64 bit absolute call.
+// If toc_offset == -2, then the destination of the call (= target) is emitted
+//                      to the constant pool and a runtime_call relocation is added
+//                      to the code buffer.
+// If toc_offset != -2, target must already be in the constant pool at
+//                      _ctableStart+toc_offset (a caller can retrieve toc_offset
+//                      from the runtime_call relocation).
+// Special handling of emitting to scratch buffer when there is no constant pool.
+// Slightly changed code pattern. We emit an additional nop if we would
+// not end emitting at a word aligned address. This is to ensure
+// an atomically patchable displacement in brasl instructions.
+//
+// A call_far_patchable comes in different flavors:
+//  - LARL(CP) / LG(CP) / BR (address in constant pool, access via CP register)
+//  - LGRL(CP) / BR          (address in constant pool, pc-relative accesss)
+//  - BRASL                  (relative address of call target coded in instruction)
+// All flavors occupy the same amount of space. Length differences are compensated
+// by leading nops, such that the instruction sequence always ends at the same
+// byte offset. This is required to keep the return offset constant.
+// Furthermore, the return address (the end of the instruction sequence) is forced
+// to be on a 4-byte boundary. This is required for atomic patching, should we ever
+// need to patch the call target of the BRASL flavor.
+// RETURN value: false, if no constant pool entry could be allocated, true otherwise.
+bool MacroAssembler::call_far_patchable(address target, int64_t tocOffset) {
+  // Get current pc and ensure word alignment for end of instr sequence.
+  const address start_pc = pc();
+  const intptr_t       start_off = offset();
+  assert(!call_far_patchable_requires_alignment_nop(start_pc), "call_far_patchable requires aligned address");
+  const ptrdiff_t      dist      = (ptrdiff_t)(target - (start_pc + 2)); // Prepend each BRASL with a nop.
+  const bool emit_target_to_pool = (tocOffset == -2) && !code_section()->scratch_emit();
+  const bool emit_relative_call  = !emit_target_to_pool &&
+                                   RelAddr::is_in_range_of_RelAddr32(dist) &&
+                                   ReoptimizeCallSequences &&
+                                   !code_section()->scratch_emit();
+
+  if (emit_relative_call) {
+    // Add padding to get the same size as below.
+    const unsigned int padding = call_far_patchable_size() - call_far_pcrelative_size();
+    unsigned int current_padding;
+    for (current_padding = 0; current_padding < padding; current_padding += nop_size()) { z_nop(); }
+    assert(current_padding == padding, "sanity");
+
+    // relative call: len = 2(nop) + 6 (brasl)
+    // CodeBlob resize cannot occur in this case because
+    // this call is emitted into pre-existing space.
+    z_nop(); // Prepend each BRASL with a nop.
+    z_brasl(Z_R14, target);
+  } else {
+    // absolute call: Get address from TOC.
+    // len = (load TOC){6|0} + (load from TOC){6} + (basr){2} = {14|8}
+    if (emit_target_to_pool) {
+      // When emitting the call for the first time, we do not need to use
+      // the pc-relative version. It will be patched anyway, when the code
+      // buffer is copied.
+      // Relocation is not needed when !ReoptimizeCallSequences.
+      relocInfo::relocType rt = ReoptimizeCallSequences ? relocInfo::runtime_call_w_cp_type : relocInfo::none;
+      AddressLiteral dest(target, rt);
+      // Store_oop_in_toc() adds dest to the constant table. As side effect, this kills
+      // inst_mark(). Reset if possible.
+      bool reset_mark = (inst_mark() == pc());
+      tocOffset = store_oop_in_toc(dest);
+      if (reset_mark) { set_inst_mark(); }
+      if (tocOffset == -1) {
+        return false; // Couldn't create constant pool entry.
+      }
+    }
+    assert(offset() == start_off, "emit no code before this point!");
+
+    address tocPos = pc() + tocOffset;
+    if (emit_target_to_pool) {
+      tocPos = code()->consts()->start() + tocOffset;
+    }
+    load_long_pcrelative(Z_R14, tocPos);
+    z_basr(Z_R14, Z_R14);
+  }
+
+#ifdef ASSERT
+  // Assert that we can identify the emitted call.
+  assert(is_call_far_patchable_at(addr_at(start_off)), "can't identify emitted call");
+  assert(offset() == start_off+call_far_patchable_size(), "wrong size");
+
+  if (emit_target_to_pool) {
+    assert(get_dest_of_call_far_patchable_at(addr_at(start_off), code()->consts()->start()) == target,
+           "wrong encoding of dest address");
+  }
+#endif
+  return true; // success
+}
+
+// Identify a call_far_patchable instruction.
+// For more detailed information see header comment of call_far_patchable.
+bool MacroAssembler::is_call_far_patchable_at(address instruction_addr) {
+  return is_call_far_patchable_variant2_at(instruction_addr)  || // short version: BRASL
+         is_call_far_patchable_variant0_at(instruction_addr);    // long version LARL + LG + BASR
+}
+
+// Does the call_far_patchable instruction use a pc-relative encoding
+// of the call destination?
+bool MacroAssembler::is_call_far_patchable_pcrelative_at(address instruction_addr) {
+  // Variant 2 is pc-relative.
+  return is_call_far_patchable_variant2_at(instruction_addr);
+}
+
+bool MacroAssembler::is_call_far_pcrelative(address instruction_addr) {
+  // Prepend each BRASL with a nop.
+  return is_z_nop(instruction_addr) && is_z_brasl(instruction_addr + nop_size());  // Match at position after one nop required.
+}
+
+// Set destination address of a call_far_patchable instruction.
+void MacroAssembler::set_dest_of_call_far_patchable_at(address instruction_addr, address dest, int64_t tocOffset) {
+  ResourceMark rm;
+
+  // Now that CP entry is verified, patch call to a pc-relative call (if circumstances permit).
+  int code_size = MacroAssembler::call_far_patchable_size();
+  CodeBuffer buf(instruction_addr, code_size);
+  MacroAssembler masm(&buf);
+  masm.call_far_patchable(dest, tocOffset);
+  ICache::invalidate_range(instruction_addr, code_size); // Empty on z.
+}
+
+// Get dest address of a call_far_patchable instruction.
+address MacroAssembler::get_dest_of_call_far_patchable_at(address instruction_addr, address ctable) {
+  // Dynamic TOC: absolute address in constant pool.
+  // Check variant2 first, it is more frequent.
+
+  // Relative address encoded in call instruction.
+  if (is_call_far_patchable_variant2_at(instruction_addr)) {
+    return MacroAssembler::get_target_addr_pcrel(instruction_addr + nop_size()); // Prepend each BRASL with a nop.
+
+  // Absolute address in constant pool.
+  } else if (is_call_far_patchable_variant0_at(instruction_addr)) {
+    address iaddr = instruction_addr;
+
+    long    tocOffset = get_load_const_from_toc_offset(iaddr);
+    address tocLoc    = iaddr + tocOffset;
+    return *(address *)(tocLoc);
+  } else {
+    fprintf(stderr, "MacroAssembler::get_dest_of_call_far_patchable_at has a problem at %p:\n", instruction_addr);
+    fprintf(stderr, "not a call_far_patchable: %16.16lx %16.16lx, len = %d\n",
+            *(unsigned long*)instruction_addr,
+            *(unsigned long*)(instruction_addr+8),
+            call_far_patchable_size());
+    Disassembler::decode(instruction_addr, instruction_addr+call_far_patchable_size());
+    ShouldNotReachHere();
+    return NULL;
+  }
+}
+
+void MacroAssembler::align_call_far_patchable(address pc) {
+  if (call_far_patchable_requires_alignment_nop(pc)) { z_nop(); }
+}
+
+void MacroAssembler::check_and_handle_earlyret(Register java_thread) {
+}
+
+void MacroAssembler::check_and_handle_popframe(Register java_thread) {
+}
+
+// Read from the polling page.
+// Use TM or TMY instruction, depending on read offset.
+//   offset = 0: Use TM, safepoint polling.
+//   offset < 0: Use TMY, profiling safepoint polling.
+void MacroAssembler::load_from_polling_page(Register polling_page_address, int64_t offset) {
+  if (Immediate::is_uimm12(offset)) {
+    z_tm(offset, polling_page_address, mask_safepoint);
+  } else {
+    z_tmy(offset, polling_page_address, mask_profiling);
+  }
+}
+
+// Check whether z_instruction is a read access to the polling page
+// which was emitted by load_from_polling_page(..).
+bool MacroAssembler::is_load_from_polling_page(address instr_loc) {
+  unsigned long z_instruction;
+  unsigned int  ilen = get_instruction(instr_loc, &z_instruction);
+
+  if (ilen == 2) { return false; } // It's none of the allowed instructions.
+
+  if (ilen == 4) {
+    if (!is_z_tm(z_instruction)) { return false; } // It's len=4, but not a z_tm. fail.
+
+    int ms = inv_mask(z_instruction,8,32);  // mask
+    int ra = inv_reg(z_instruction,16,32);  // base register
+    int ds = inv_uimm12(z_instruction);     // displacement
+
+    if (!(ds == 0 && ra != 0 && ms == mask_safepoint)) {
+      return false; // It's not a z_tm(0, ra, mask_safepoint). Fail.
+    }
+
+  } else { /* if (ilen == 6) */
+
+    assert(!is_z_lg(z_instruction), "old form (LG) polling page access. Please fix and use TM(Y).");
+
+    if (!is_z_tmy(z_instruction)) { return false; } // It's len=6, but not a z_tmy. fail.
+
+    int ms = inv_mask(z_instruction,8,48);  // mask
+    int ra = inv_reg(z_instruction,16,48);  // base register
+    int ds = inv_simm20(z_instruction);     // displacement
+  }
+
+  return true;
+}
+
+// Extract poll address from instruction and ucontext.
+address MacroAssembler::get_poll_address(address instr_loc, void* ucontext) {
+  assert(ucontext != NULL, "must have ucontext");
+  ucontext_t* uc = (ucontext_t*) ucontext;
+  unsigned long z_instruction;
+  unsigned int ilen = get_instruction(instr_loc, &z_instruction);
+
+  if (ilen == 4 && is_z_tm(z_instruction)) {
+    int ra = inv_reg(z_instruction, 16, 32);  // base register
+    int ds = inv_uimm12(z_instruction);       // displacement
+    address addr = (address)uc->uc_mcontext.gregs[ra];
+    return addr + ds;
+  } else if (ilen == 6 && is_z_tmy(z_instruction)) {
+    int ra = inv_reg(z_instruction, 16, 48);  // base register
+    int ds = inv_simm20(z_instruction);       // displacement
+    address addr = (address)uc->uc_mcontext.gregs[ra];
+    return addr + ds;
+  }
+
+  ShouldNotReachHere();
+  return NULL;
+}
+
+// Extract poll register from instruction.
+uint MacroAssembler::get_poll_register(address instr_loc) {
+  unsigned long z_instruction;
+  unsigned int ilen = get_instruction(instr_loc, &z_instruction);
+
+  if (ilen == 4 && is_z_tm(z_instruction)) {
+    return (uint)inv_reg(z_instruction, 16, 32);  // base register
+  } else if (ilen == 6 && is_z_tmy(z_instruction)) {
+    return (uint)inv_reg(z_instruction, 16, 48);  // base register
+  }
+
+  ShouldNotReachHere();
+  return 0;
+}
+
+bool MacroAssembler::is_memory_serialization(int instruction, JavaThread* thread, void* ucontext) {
+  ShouldNotCallThis();
+  return false;
+}
+
+// Write serialization page so VM thread can do a pseudo remote membar
+// We use the current thread pointer to calculate a thread specific
+// offset to write to within the page. This minimizes bus traffic
+// due to cache line collision.
+void MacroAssembler::serialize_memory(Register thread, Register tmp1, Register tmp2) {
+  assert_different_registers(tmp1, tmp2);
+  z_sllg(tmp2, thread, os::get_serialize_page_shift_count());
+  load_const_optimized(tmp1, (long) os::get_memory_serialize_page());
+
+  int mask = os::get_serialize_page_mask();
+  if (Immediate::is_uimm16(mask)) {
+    z_nill(tmp2, mask);
+    z_llghr(tmp2, tmp2);
+  } else {
+    z_nilf(tmp2, mask);
+    z_llgfr(tmp2, tmp2);
+  }
+
+  z_release();
+  z_st(Z_R0, 0, tmp2, tmp1);
+}
+
+// Don't rely on register locking, always use Z_R1 as scratch register instead.
+void MacroAssembler::bang_stack_with_offset(int offset) {
+  // Stack grows down, caller passes positive offset.
+  assert(offset > 0, "must bang with positive offset");
+  if (Displacement::is_validDisp(-offset)) {
+    z_tmy(-offset, Z_SP, mask_stackbang);
+  } else {
+    add2reg(Z_R1, -offset, Z_SP);    // Do not destroy Z_SP!!!
+    z_tm(0, Z_R1, mask_stackbang);  // Just banging.
+  }
+}
+
+// Defines obj, preserves var_size_in_bytes, okay for t2 == var_size_in_bytes.
+void MacroAssembler::tlab_allocate(Register obj,
+                                   Register var_size_in_bytes,
+                                   int con_size_in_bytes,
+                                   Register t1,
+                                   Label& slow_case) {
+  assert_different_registers(obj, var_size_in_bytes, t1);
+  Register end = t1;
+  Register thread = Z_thread;
+
+  z_lg(obj, Address(thread, JavaThread::tlab_top_offset()));
+  if (var_size_in_bytes == noreg) {
+    z_lay(end, Address(obj, con_size_in_bytes));
+  } else {
+    z_lay(end, Address(obj, var_size_in_bytes));
+  }
+  z_cg(end, Address(thread, JavaThread::tlab_end_offset()));
+  branch_optimized(bcondHigh, slow_case);
+
+  // Update the tlab top pointer.
+  z_stg(end, Address(thread, JavaThread::tlab_top_offset()));
+
+  // Recover var_size_in_bytes if necessary.
+  if (var_size_in_bytes == end) {
+    z_sgr(var_size_in_bytes, obj);
+  }
+}
+
+// Emitter for interface method lookup.
+//   input: recv_klass, intf_klass, itable_index
+//   output: method_result
+//   kills: itable_index, temp1_reg, Z_R0, Z_R1
+// TODO: Temp2_reg is unused. we may use this emitter also in the itable stubs.
+// If the register is still not needed then, remove it.
+void MacroAssembler::lookup_interface_method(Register           recv_klass,
+                                             Register           intf_klass,
+                                             RegisterOrConstant itable_index,
+                                             Register           method_result,
+                                             Register           temp1_reg,
+                                             Register           temp2_reg,
+                                             Label&             no_such_interface) {
+
+  const Register vtable_len = temp1_reg;    // Used to compute itable_entry_addr.
+  const Register itable_entry_addr = Z_R1_scratch;
+  const Register itable_interface = Z_R0_scratch;
+
+  BLOCK_COMMENT("lookup_interface_method {");
+
+  // Load start of itable entries into itable_entry_addr.
+  z_llgf(vtable_len, Address(recv_klass, InstanceKlass::vtable_length_offset()));
+  z_sllg(vtable_len, vtable_len, exact_log2(vtableEntry::size_in_bytes()));
+
+  // Loop over all itable entries until desired interfaceOop(Rinterface) found.
+  const int vtable_base_offset = in_bytes(InstanceKlass::vtable_start_offset());
+
+  add2reg_with_index(itable_entry_addr,
+                     vtable_base_offset + itableOffsetEntry::interface_offset_in_bytes(),
+                     recv_klass, vtable_len);
+
+  const int itable_offset_search_inc = itableOffsetEntry::size() * wordSize;
+  Label     search;
+
+  bind(search);
+
+  // Handle IncompatibleClassChangeError.
+  // If the entry is NULL then we've reached the end of the table
+  // without finding the expected interface, so throw an exception.
+  load_and_test_long(itable_interface, Address(itable_entry_addr));
+  z_bre(no_such_interface);
+
+  add2reg(itable_entry_addr, itable_offset_search_inc);
+  z_cgr(itable_interface, intf_klass);
+  z_brne(search);
+
+  // Entry found and itable_entry_addr points to it, get offset of vtable for interface.
+
+  const int vtable_offset_offset = (itableOffsetEntry::offset_offset_in_bytes() -
+                                    itableOffsetEntry::interface_offset_in_bytes()) -
+                                   itable_offset_search_inc;
+
+  // Compute itableMethodEntry and get method and entry point
+  // we use addressing with index and displacement, since the formula
+  // for computing the entry's offset has a fixed and a dynamic part,
+  // the latter depending on the matched interface entry and on the case,
+  // that the itable index has been passed as a register, not a constant value.
+  int method_offset = itableMethodEntry::method_offset_in_bytes();
+                           // Fixed part (displacement), common operand.
+  Register itable_offset;  // Dynamic part (index register).
+
+  if (itable_index.is_register()) {
+     // Compute the method's offset in that register, for the formula, see the
+     // else-clause below.
+     itable_offset = itable_index.as_register();
+
+     z_sllg(itable_offset, itable_offset, exact_log2(itableMethodEntry::size() * wordSize));
+     z_agf(itable_offset, vtable_offset_offset, itable_entry_addr);
+  } else {
+    itable_offset = Z_R1_scratch;
+    // Displacement increases.
+    method_offset += itableMethodEntry::size() * wordSize * itable_index.as_constant();
+
+    // Load index from itable.
+    z_llgf(itable_offset, vtable_offset_offset, itable_entry_addr);
+  }
+
+  // Finally load the method's oop.
+  z_lg(method_result, method_offset, itable_offset, recv_klass);
+  BLOCK_COMMENT("} lookup_interface_method");
+}
+
+// Lookup for virtual method invocation.
+void MacroAssembler::lookup_virtual_method(Register           recv_klass,
+                                           RegisterOrConstant vtable_index,
+                                           Register           method_result) {
+  assert_different_registers(recv_klass, vtable_index.register_or_noreg());
+  assert(vtableEntry::size() * wordSize == wordSize,
+         "else adjust the scaling in the code below");
+
+  BLOCK_COMMENT("lookup_virtual_method {");
+
+  const int base = in_bytes(Klass::vtable_start_offset());
+
+  if (vtable_index.is_constant()) {
+    // Load with base + disp.
+    Address vtable_entry_addr(recv_klass,
+                              vtable_index.as_constant() * wordSize +
+                              base +
+                              vtableEntry::method_offset_in_bytes());
+
+    z_lg(method_result, vtable_entry_addr);
+  } else {
+    // Shift index properly and load with base + index + disp.
+    Register vindex = vtable_index.as_register();
+    Address  vtable_entry_addr(recv_klass, vindex,
+                               base + vtableEntry::method_offset_in_bytes());
+
+    z_sllg(vindex, vindex, exact_log2(wordSize));
+    z_lg(method_result, vtable_entry_addr);
+  }
+  BLOCK_COMMENT("} lookup_virtual_method");
+}
+
+// Factor out code to call ic_miss_handler.
+// Generate code to call the inline cache miss handler.
+//
+// In most cases, this code will be generated out-of-line.
+// The method parameters are intended to provide some variability.
+//   ICM          - Label which has to be bound to the start of useful code (past any traps).
+//   trapMarker   - Marking byte for the generated illtrap instructions (if any).
+//                  Any value except 0x00 is supported.
+//                  = 0x00 - do not generate illtrap instructions.
+//                         use nops to fill ununsed space.
+//   requiredSize - required size of the generated code. If the actually
+//                  generated code is smaller, use padding instructions to fill up.
+//                  = 0 - no size requirement, no padding.
+//   scratch      - scratch register to hold branch target address.
+//
+//  The method returns the code offset of the bound label.
+unsigned int MacroAssembler::call_ic_miss_handler(Label& ICM, int trapMarker, int requiredSize, Register scratch) {
+  intptr_t startOffset = offset();
+
+  // Prevent entry at content_begin().
+  if (trapMarker != 0) {
+    z_illtrap(trapMarker);
+  }
+
+  // Load address of inline cache miss code into scratch register
+  // and branch to cache miss handler.
+  BLOCK_COMMENT("IC miss handler {");
+  BIND(ICM);
+  unsigned int   labelOffset = offset();
+  AddressLiteral icmiss(SharedRuntime::get_ic_miss_stub());
+
+  load_const_optimized(scratch, icmiss);
+  z_br(scratch);
+
+  // Fill unused space.
+  if (requiredSize > 0) {
+    while ((offset() - startOffset) < requiredSize) {
+      if (trapMarker == 0) {
+        z_nop();
+      } else {
+        z_illtrap(trapMarker);
+      }
+    }
+  }
+  BLOCK_COMMENT("} IC miss handler");
+  return labelOffset;
+}
+
+void MacroAssembler::nmethod_UEP(Label& ic_miss) {
+  Register ic_reg       = as_Register(Matcher::inline_cache_reg_encode());
+  int      klass_offset = oopDesc::klass_offset_in_bytes();
+  if (!ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(klass_offset)) {
+    if (VM_Version::has_CompareBranch()) {
+      z_cgij(Z_ARG1, 0, Assembler::bcondEqual, ic_miss);
+    } else {
+      z_ltgr(Z_ARG1, Z_ARG1);
+      z_bre(ic_miss);
+    }
+  }
+  // Compare cached class against klass from receiver.
+  compare_klass_ptr(ic_reg, klass_offset, Z_ARG1, false);
+  z_brne(ic_miss);
+}
+
+void MacroAssembler::check_klass_subtype_fast_path(Register   sub_klass,
+                                                   Register   super_klass,
+                                                   Register   temp1_reg,
+                                                   Label*     L_success,
+                                                   Label*     L_failure,
+                                                   Label*     L_slow_path,
+                                                   RegisterOrConstant super_check_offset) {
+
+  const int sc_offset  = in_bytes(Klass::secondary_super_cache_offset());
+  const int sco_offset = in_bytes(Klass::super_check_offset_offset());
+
+  bool must_load_sco = (super_check_offset.constant_or_zero() == -1);
+  bool need_slow_path = (must_load_sco ||
+                         super_check_offset.constant_or_zero() == sc_offset);
+
+  // Input registers must not overlap.
+  assert_different_registers(sub_klass, super_klass, temp1_reg);
+  if (super_check_offset.is_register()) {
+    assert_different_registers(sub_klass, super_klass,
+                               super_check_offset.as_register());
+  } else if (must_load_sco) {
+    assert(temp1_reg != noreg, "supply either a temp or a register offset");
+  }
+
+  const Register Rsuper_check_offset = temp1_reg;
+
+  NearLabel L_fallthrough;
+  int label_nulls = 0;
+  if (L_success == NULL)   { L_success   = &L_fallthrough; label_nulls++; }
+  if (L_failure == NULL)   { L_failure   = &L_fallthrough; label_nulls++; }
+  if (L_slow_path == NULL) { L_slow_path = &L_fallthrough; label_nulls++; }
+  assert(label_nulls <= 1 ||
+         (L_slow_path == &L_fallthrough && label_nulls <= 2 && !need_slow_path),
+         "at most one NULL in the batch, usually");
+
+  BLOCK_COMMENT("check_klass_subtype_fast_path {");
+  // If the pointers are equal, we are done (e.g., String[] elements).
+  // This self-check enables sharing of secondary supertype arrays among
+  // non-primary types such as array-of-interface. Otherwise, each such
+  // type would need its own customized SSA.
+  // We move this check to the front of the fast path because many
+  // type checks are in fact trivially successful in this manner,
+  // so we get a nicely predicted branch right at the start of the check.
+  compare64_and_branch(sub_klass, super_klass, bcondEqual, *L_success);
+
+  // Check the supertype display, which is uint.
+  if (must_load_sco) {
+    z_llgf(Rsuper_check_offset, sco_offset, super_klass);
+    super_check_offset = RegisterOrConstant(Rsuper_check_offset);
+  }
+  Address super_check_addr(sub_klass, super_check_offset, 0);
+  z_cg(super_klass, super_check_addr); // compare w/ displayed supertype
+
+  // This check has worked decisively for primary supers.
+  // Secondary supers are sought in the super_cache ('super_cache_addr').
+  // (Secondary supers are interfaces and very deeply nested subtypes.)
+  // This works in the same check above because of a tricky aliasing
+  // between the super_cache and the primary super display elements.
+  // (The 'super_check_addr' can address either, as the case requires.)
+  // Note that the cache is updated below if it does not help us find
+  // what we need immediately.
+  // So if it was a primary super, we can just fail immediately.
+  // Otherwise, it's the slow path for us (no success at this point).
+
+  // Hacked jmp, which may only be used just before L_fallthrough.
+#define final_jmp(label)                                                \
+  if (&(label) == &L_fallthrough) { /*do nothing*/ }                    \
+  else                            { branch_optimized(Assembler::bcondAlways, label); } /*omit semicolon*/
+
+  if (super_check_offset.is_register()) {
+    branch_optimized(Assembler::bcondEqual, *L_success);
+    z_cfi(super_check_offset.as_register(), sc_offset);
+    if (L_failure == &L_fallthrough) {
+      branch_optimized(Assembler::bcondEqual, *L_slow_path);
+    } else {
+      branch_optimized(Assembler::bcondNotEqual, *L_failure);
+      final_jmp(*L_slow_path);
+    }
+  } else if (super_check_offset.as_constant() == sc_offset) {
+    // Need a slow path; fast failure is impossible.
+    if (L_slow_path == &L_fallthrough) {
+      branch_optimized(Assembler::bcondEqual, *L_success);
+    } else {
+      branch_optimized(Assembler::bcondNotEqual, *L_slow_path);
+      final_jmp(*L_success);
+    }
+  } else {
+    // No slow path; it's a fast decision.
+    if (L_failure == &L_fallthrough) {
+      branch_optimized(Assembler::bcondEqual, *L_success);
+    } else {
+      branch_optimized(Assembler::bcondNotEqual, *L_failure);
+      final_jmp(*L_success);
+    }
+  }
+
+  bind(L_fallthrough);
+#undef local_brc
+#undef final_jmp
+  BLOCK_COMMENT("} check_klass_subtype_fast_path");
+  // fallthru (to slow path)
+}
+
+void MacroAssembler::check_klass_subtype_slow_path(Register Rsubklass,
+                                                   Register Rsuperklass,
+                                                   Register Rarray_ptr,  // tmp
+                                                   Register Rlength,     // tmp
+                                                   Label* L_success,
+                                                   Label* L_failure) {
+  // Input registers must not overlap.
+  // Also check for R1 which is explicitely used here.
+  assert_different_registers(Z_R1, Rsubklass, Rsuperklass, Rarray_ptr, Rlength);
+  NearLabel L_fallthrough, L_loop;
+  int label_nulls = 0;
+  if (L_success == NULL) { L_success = &L_fallthrough; label_nulls++; }
+  if (L_failure == NULL) { L_failure = &L_fallthrough; label_nulls++; }
+  assert(label_nulls <= 1, "at most one NULL in the batch");
+
+  const int ss_offset = in_bytes(Klass::secondary_supers_offset());
+  const int sc_offset = in_bytes(Klass::secondary_super_cache_offset());
+
+  const int length_offset = Array<Klass*>::length_offset_in_bytes();
+  const int base_offset   = Array<Klass*>::base_offset_in_bytes();
+
+  // Hacked jmp, which may only be used just before L_fallthrough.
+#define final_jmp(label)                                                \
+  if (&(label) == &L_fallthrough) { /*do nothing*/ }                    \
+  else                            branch_optimized(Assembler::bcondAlways, label) /*omit semicolon*/
+
+  NearLabel loop_iterate, loop_count, match;
+
+  BLOCK_COMMENT("check_klass_subtype_slow_path {");
+  z_lg(Rarray_ptr, ss_offset, Rsubklass);
+
+  load_and_test_int(Rlength, Address(Rarray_ptr, length_offset));
+  branch_optimized(Assembler::bcondZero, *L_failure);
+
+  // Oops in table are NO MORE compressed.
+  z_cg(Rsuperklass, base_offset, Rarray_ptr); // Check array element for match.
+  z_bre(match);                               // Shortcut for array length = 1.
+
+  // No match yet, so we must walk the array's elements.
+  z_lngfr(Rlength, Rlength);
+  z_sllg(Rlength, Rlength, LogBytesPerWord); // -#bytes of cache array
+  z_llill(Z_R1, BytesPerWord);               // Set increment/end index.
+  add2reg(Rlength, 2 * BytesPerWord);        // start index  = -(n-2)*BytesPerWord
+  z_slgr(Rarray_ptr, Rlength);               // start addr: +=  (n-2)*BytesPerWord
+  z_bru(loop_count);
+
+  BIND(loop_iterate);
+  z_cg(Rsuperklass, base_offset, Rlength, Rarray_ptr); // Check array element for match.
+  z_bre(match);
+  BIND(loop_count);
+  z_brxlg(Rlength, Z_R1, loop_iterate);
+
+  // Rsuperklass not found among secondary super classes -> failure.
+  branch_optimized(Assembler::bcondAlways, *L_failure);
+
+  // Got a hit. Return success (zero result). Set cache.
+  // Cache load doesn't happen here. For speed it is directly emitted by the compiler.
+
+  BIND(match);
+
+  z_stg(Rsuperklass, sc_offset, Rsubklass); // Save result to cache.
+
+  final_jmp(*L_success);
+
+  // Exit to the surrounding code.
+  BIND(L_fallthrough);
+#undef local_brc
+#undef final_jmp
+  BLOCK_COMMENT("} check_klass_subtype_slow_path");
+}
+
+// Emitter for combining fast and slow path.
+void MacroAssembler::check_klass_subtype(Register sub_klass,
+                                         Register super_klass,
+                                         Register temp1_reg,
+                                         Register temp2_reg,
+                                         Label&   L_success) {
+  NearLabel failure;
+  BLOCK_COMMENT(err_msg("check_klass_subtype(%s subclass of %s) {", sub_klass->name(), super_klass->name()));
+  check_klass_subtype_fast_path(sub_klass, super_klass, temp1_reg,
+                                &L_success, &failure, NULL);
+  check_klass_subtype_slow_path(sub_klass, super_klass,
+                                temp1_reg, temp2_reg, &L_success, NULL);
+  BIND(failure);
+  BLOCK_COMMENT("} check_klass_subtype");
+}
+
+// Increment a counter at counter_address when the eq condition code is
+// set. Kills registers tmp1_reg and tmp2_reg and preserves the condition code.
+void MacroAssembler::increment_counter_eq(address counter_address, Register tmp1_reg, Register tmp2_reg) {
+  Label l;
+  z_brne(l);
+  load_const(tmp1_reg, counter_address);
+  add2mem_32(Address(tmp1_reg), 1, tmp2_reg);
+  z_cr(tmp1_reg, tmp1_reg); // Set cc to eq.
+  bind(l);
+}
+
+// Semantics are dependent on the slow_case label:
+//   If the slow_case label is not NULL, failure to biased-lock the object
+//   transfers control to the location of the slow_case label. If the
+//   object could be biased-locked, control is transferred to the done label.
+//   The condition code is unpredictable.
+//
+//   If the slow_case label is NULL, failure to biased-lock the object results
+//   in a transfer of control to the done label with a condition code of not_equal.
+//   If the biased-lock could be successfully obtained, control is transfered to
+//   the done label with a condition code of equal.
+//   It is mandatory to react on the condition code At the done label.
+//
+void MacroAssembler::biased_locking_enter(Register  obj_reg,
+                                          Register  mark_reg,
+                                          Register  temp_reg,
+                                          Register  temp2_reg,    // May be Z_RO!
+                                          Label    &done,
+                                          Label    *slow_case) {
+  assert(UseBiasedLocking, "why call this otherwise?");
+  assert_different_registers(obj_reg, mark_reg, temp_reg, temp2_reg);
+
+  Label cas_label; // Try, if implemented, CAS locking. Fall thru to slow path otherwise.
+
+  BLOCK_COMMENT("biased_locking_enter {");
+
+  // Biased locking
+  // See whether the lock is currently biased toward our thread and
+  // whether the epoch is still valid.
+  // Note that the runtime guarantees sufficient alignment of JavaThread
+  // pointers to allow age to be placed into low bits.
+  assert(markOopDesc::age_shift == markOopDesc::lock_bits + markOopDesc::biased_lock_bits,
+         "biased locking makes assumptions about bit layout");
+  z_lr(temp_reg, mark_reg);
+  z_nilf(temp_reg, markOopDesc::biased_lock_mask_in_place);
+  z_chi(temp_reg, markOopDesc::biased_lock_pattern);
+  z_brne(cas_label);  // Try cas if object is not biased, i.e. cannot be biased locked.
+
+  load_prototype_header(temp_reg, obj_reg);
+  load_const_optimized(temp2_reg, ~((int) markOopDesc::age_mask_in_place));
+
+  z_ogr(temp_reg, Z_thread);
+  z_xgr(temp_reg, mark_reg);
+  z_ngr(temp_reg, temp2_reg);
+  if (PrintBiasedLockingStatistics) {
+    increment_counter_eq((address) BiasedLocking::biased_lock_entry_count_addr(), mark_reg, temp2_reg);
+    // Restore mark_reg.
+    z_lg(mark_reg, oopDesc::mark_offset_in_bytes(), obj_reg);
+  }
+  branch_optimized(Assembler::bcondEqual, done);  // Biased lock obtained, return success.
+
+  Label try_revoke_bias;
+  Label try_rebias;
+  Address mark_addr = Address(obj_reg, oopDesc::mark_offset_in_bytes());
+
+  //----------------------------------------------------------------------------
+  // At this point we know that the header has the bias pattern and
+  // that we are not the bias owner in the current epoch. We need to
+  // figure out more details about the state of the header in order to
+  // know what operations can be legally performed on the object's
+  // header.
+
+  // If the low three bits in the xor result aren't clear, that means
+  // the prototype header is no longer biased and we have to revoke
+  // the bias on this object.
+  z_tmll(temp_reg, markOopDesc::biased_lock_mask_in_place);
+  z_brnaz(try_revoke_bias);
+
+  // Biasing is still enabled for this data type. See whether the
+  // epoch of the current bias is still valid, meaning that the epoch
+  // bits of the mark word are equal to the epoch bits of the
+  // prototype header. (Note that the prototype header's epoch bits
+  // only change at a safepoint.) If not, attempt to rebias the object
+  // toward the current thread. Note that we must be absolutely sure
+  // that the current epoch is invalid in order to do this because
+  // otherwise the manipulations it performs on the mark word are
+  // illegal.
+  z_tmll(temp_reg, markOopDesc::epoch_mask_in_place);
+  z_brnaz(try_rebias);
+
+  //----------------------------------------------------------------------------
+  // The epoch of the current bias is still valid but we know nothing
+  // about the owner; it might be set or it might be clear. Try to
+  // acquire the bias of the object using an atomic operation. If this
+  // fails we will go in to the runtime to revoke the object's bias.
+  // Note that we first construct the presumed unbiased header so we
+  // don't accidentally blow away another thread's valid bias.
+  z_nilf(mark_reg, markOopDesc::biased_lock_mask_in_place | markOopDesc::age_mask_in_place |
+         markOopDesc::epoch_mask_in_place);
+  z_lgr(temp_reg, Z_thread);
+  z_llgfr(mark_reg, mark_reg);
+  z_ogr(temp_reg, mark_reg);
+
+  assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
+
+  z_csg(mark_reg, temp_reg, 0, obj_reg);
+
+  // If the biasing toward our thread failed, this means that
+  // another thread succeeded in biasing it toward itself and we
+  // need to revoke that bias. The revocation will occur in the
+  // interpreter runtime in the slow case.
+
+  if (PrintBiasedLockingStatistics) {
+    increment_counter_eq((address) BiasedLocking::anonymously_biased_lock_entry_count_addr(),
+                         temp_reg, temp2_reg);
+  }
+  if (slow_case != NULL) {
+    branch_optimized(Assembler::bcondNotEqual, *slow_case); // Biased lock not obtained, need to go the long way.
+  }
+  branch_optimized(Assembler::bcondAlways, done);           // Biased lock status given in condition code.
+
+  //----------------------------------------------------------------------------
+  bind(try_rebias);
+  // At this point we know the epoch has expired, meaning that the
+  // current "bias owner", if any, is actually invalid. Under these
+  // circumstances _only_, we are allowed to use the current header's
+  // value as the comparison value when doing the cas to acquire the
+  // bias in the current epoch. In other words, we allow transfer of
+  // the bias from one thread to another directly in this situation.
+
+  z_nilf(mark_reg, markOopDesc::biased_lock_mask_in_place | markOopDesc::age_mask_in_place | markOopDesc::epoch_mask_in_place);
+  load_prototype_header(temp_reg, obj_reg);
+  z_llgfr(mark_reg, mark_reg);
+
+  z_ogr(temp_reg, Z_thread);
+
+  assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
+
+  z_csg(mark_reg, temp_reg, 0, obj_reg);
+
+  // If the biasing toward our thread failed, this means that
+  // another thread succeeded in biasing it toward itself and we
+  // need to revoke that bias. The revocation will occur in the
+  // interpreter runtime in the slow case.
+
+  if (PrintBiasedLockingStatistics) {
+    increment_counter_eq((address) BiasedLocking::rebiased_lock_entry_count_addr(), temp_reg, temp2_reg);
+  }
+  if (slow_case != NULL) {
+    branch_optimized(Assembler::bcondNotEqual, *slow_case);  // Biased lock not obtained, need to go the long way.
+  }
+  z_bru(done);           // Biased lock status given in condition code.
+
+  //----------------------------------------------------------------------------
+  bind(try_revoke_bias);
+  // The prototype mark in the klass doesn't have the bias bit set any
+  // more, indicating that objects of this data type are not supposed
+  // to be biased any more. We are going to try to reset the mark of
+  // this object to the prototype value and fall through to the
+  // CAS-based locking scheme. Note that if our CAS fails, it means
+  // that another thread raced us for the privilege of revoking the
+  // bias of this particular object, so it's okay to continue in the
+  // normal locking code.
+  load_prototype_header(temp_reg, obj_reg);
+
+  assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
+
+  z_csg(mark_reg, temp_reg, 0, obj_reg);
+
+  // Fall through to the normal CAS-based lock, because no matter what
+  // the result of the above CAS, some thread must have succeeded in
+  // removing the bias bit from the object's header.
+  if (PrintBiasedLockingStatistics) {
+    // z_cgr(mark_reg, temp2_reg);
+    increment_counter_eq((address) BiasedLocking::revoked_lock_entry_count_addr(), temp_reg, temp2_reg);
+  }
+
+  bind(cas_label);
+  BLOCK_COMMENT("} biased_locking_enter");
+}
+
+void MacroAssembler::biased_locking_exit(Register mark_addr, Register temp_reg, Label& done) {
+  // Check for biased locking unlock case, which is a no-op
+  // Note: we do not have to check the thread ID for two reasons.
+  // First, the interpreter checks for IllegalMonitorStateException at
+  // a higher level. Second, if the bias was revoked while we held the
+  // lock, the object could not be rebiased toward another thread, so
+  // the bias bit would be clear.
+  BLOCK_COMMENT("biased_locking_exit {");
+
+  z_lg(temp_reg, 0, mark_addr);
+  z_nilf(temp_reg, markOopDesc::biased_lock_mask_in_place);
+
+  z_chi(temp_reg, markOopDesc::biased_lock_pattern);
+  z_bre(done);
+  BLOCK_COMMENT("} biased_locking_exit");
+}
+
+void MacroAssembler::compiler_fast_lock_object(Register oop, Register box, Register temp1, Register temp2, bool try_bias) {
+  Register displacedHeader = temp1;
+  Register currentHeader = temp1;
+  Register temp = temp2;
+  NearLabel done, object_has_monitor;
+
+  BLOCK_COMMENT("compiler_fast_lock_object {");
+
+  // Load markOop from oop into mark.
+  z_lg(displacedHeader, 0, oop);
+
+  if (try_bias) {
+    biased_locking_enter(oop, displacedHeader, temp, Z_R0, done);
+  }
+
+  // Handle existing monitor.
+  if ((EmitSync & 0x01) == 0) {
+    // The object has an existing monitor iff (mark & monitor_value) != 0.
+    guarantee(Immediate::is_uimm16(markOopDesc::monitor_value), "must be half-word");
+    z_lr(temp, displacedHeader);
+    z_nill(temp, markOopDesc::monitor_value);
+    z_brne(object_has_monitor);
+  }
+
+  // Set mark to markOop | markOopDesc::unlocked_value.
+  z_oill(displacedHeader, markOopDesc::unlocked_value);
+
+  // Load Compare Value application register.
+
+  // Initialize the box (must happen before we update the object mark).
+  z_stg(displacedHeader, BasicLock::displaced_header_offset_in_bytes(), box);
+
+  // Memory Fence (in cmpxchgd)
+  // Compare object markOop with mark and if equal exchange scratch1 with object markOop.
+
+  // If the compare-and-swap succeeded, then we found an unlocked object and we
+  // have now locked it.
+  z_csg(displacedHeader, box, 0, oop);
+  assert(currentHeader==displacedHeader, "must be same register"); // Identified two registers from z/Architecture.
+  z_bre(done);
+
+  // We did not see an unlocked object so try the fast recursive case.
+
+  z_sgr(currentHeader, Z_SP);
+  load_const_optimized(temp, (~(os::vm_page_size()-1) | markOopDesc::lock_mask_in_place));
+
+  z_ngr(currentHeader, temp);
+  //   z_brne(done);
+  //   z_release();
+  z_stg(currentHeader/*==0 or not 0*/, BasicLock::displaced_header_offset_in_bytes(), box);
+
+  z_bru(done);
+
+  if ((EmitSync & 0x01) == 0) {
+    Register zero = temp;
+    Register monitor_tagged = displacedHeader; // Tagged with markOopDesc::monitor_value.
+    bind(object_has_monitor);
+    // The object's monitor m is unlocked iff m->owner == NULL,
+    // otherwise m->owner may contain a thread or a stack address.
+    //
+    // Try to CAS m->owner from NULL to current thread.
+    z_lghi(zero, 0);
+    // If m->owner is null, then csg succeeds and sets m->owner=THREAD and CR=EQ.
+    z_csg(zero, Z_thread, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), monitor_tagged);
+    // Store a non-null value into the box.
+    z_stg(box, BasicLock::displaced_header_offset_in_bytes(), box);
+#ifdef ASSERT
+      z_brne(done);
+      // We've acquired the monitor, check some invariants.
+      // Invariant 1: _recursions should be 0.
+      asm_assert_mem8_is_zero(OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions), monitor_tagged,
+                              "monitor->_recursions should be 0", -1);
+      z_ltgr(zero, zero); // Set CR=EQ.
+#endif
+  }
+  bind(done);
+
+  BLOCK_COMMENT("} compiler_fast_lock_object");
+  // If locking was successful, CR should indicate 'EQ'.
+  // The compiler or the native wrapper generates a branch to the runtime call
+  // _complete_monitor_locking_Java.
+}
+
+void MacroAssembler::compiler_fast_unlock_object(Register oop, Register box, Register temp1, Register temp2, bool try_bias) {
+  Register displacedHeader = temp1;
+  Register currentHeader = temp2;
+  Register temp = temp1;
+  Register monitor = temp2;
+
+  Label done, object_has_monitor;
+
+  BLOCK_COMMENT("compiler_fast_unlock_object {");
+
+  if (try_bias) {
+    biased_locking_exit(oop, currentHeader, done);
+  }
+
+  // Find the lock address and load the displaced header from the stack.
+  // if the displaced header is zero, we have a recursive unlock.
+  load_and_test_long(displacedHeader, Address(box, BasicLock::displaced_header_offset_in_bytes()));
+  z_bre(done);
+
+  // Handle existing monitor.
+  if ((EmitSync & 0x02) == 0) {
+    // The object has an existing monitor iff (mark & monitor_value) != 0.
+    z_lg(currentHeader, oopDesc::mark_offset_in_bytes(), oop);
+    guarantee(Immediate::is_uimm16(markOopDesc::monitor_value), "must be half-word");
+    z_nill(currentHeader, markOopDesc::monitor_value);
+    z_brne(object_has_monitor);
+  }
+
+  // Check if it is still a light weight lock, this is true if we see
+  // the stack address of the basicLock in the markOop of the object
+  // copy box to currentHeader such that csg does not kill it.
+  z_lgr(currentHeader, box);
+  z_csg(currentHeader, displacedHeader, 0, oop);
+  z_bru(done); // Csg sets CR as desired.
+
+  // Handle existing monitor.
+  if ((EmitSync & 0x02) == 0) {
+    bind(object_has_monitor);
+    z_lg(currentHeader, oopDesc::mark_offset_in_bytes(), oop);    // CurrentHeader is tagged with monitor_value set.
+    load_and_test_long(temp, Address(currentHeader, OM_OFFSET_NO_MONITOR_VALUE_TAG(recursions)));
+    z_brne(done);
+    load_and_test_long(temp, Address(currentHeader, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
+    z_brne(done);
+    load_and_test_long(temp, Address(currentHeader, OM_OFFSET_NO_MONITOR_VALUE_TAG(EntryList)));
+    z_brne(done);
+    load_and_test_long(temp, Address(currentHeader, OM_OFFSET_NO_MONITOR_VALUE_TAG(cxq)));
+    z_brne(done);
+    z_release();
+    z_stg(temp/*=0*/, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), currentHeader);
+  }
+
+  bind(done);
+
+  BLOCK_COMMENT("} compiler_fast_unlock_object");
+  // flag == EQ indicates success
+  // flag == NE indicates failure
+}
+
+// Write to card table for modification at store_addr - register is destroyed afterwards.
+void MacroAssembler::card_write_barrier_post(Register store_addr, Register tmp) {
+  CardTableModRefBS* bs = (CardTableModRefBS*) Universe::heap()->barrier_set();
+  assert(bs->kind() == BarrierSet::CardTableForRS ||
+         bs->kind() == BarrierSet::CardTableExtension, "wrong barrier");
+  assert_different_registers(store_addr, tmp);
+  z_srlg(store_addr, store_addr, CardTableModRefBS::card_shift);
+  load_absolute_address(tmp, (address)bs->byte_map_base);
+  z_agr(store_addr, tmp);
+  z_mvi(0, store_addr, 0); // Store byte 0.
+}
+
+#if INCLUDE_ALL_GCS
+
+//------------------------------------------------------
+// General G1 pre-barrier generator.
+// Purpose: record the previous value if it is not null.
+// All non-tmps are preserved.
+//------------------------------------------------------
+void MacroAssembler::g1_write_barrier_pre(Register           Robj,
+                                          RegisterOrConstant offset,
+                                          Register           Rpre_val,      // Ideally, this is a non-volatile register.
+                                          Register           Rval,          // Will be preserved.
+                                          Register           Rtmp1,         // If Rpre_val is volatile, either Rtmp1
+                                          Register           Rtmp2,         // or Rtmp2 has to be non-volatile..
+                                          bool               pre_val_needed // Save Rpre_val across runtime call, caller uses it.
+                                       ) {
+  Label callRuntime, filtered;
+  const int active_offset = in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_active());
+  const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_buf());
+  const int index_offset  = in_bytes(JavaThread::satb_mark_queue_offset() + SATBMarkQueue::byte_offset_of_index());
+  assert_different_registers(Rtmp1, Rtmp2, Z_R0_scratch); // None of the Rtmp<i> must be Z_R0!!
+
+  BLOCK_COMMENT("g1_write_barrier_pre {");
+
+  // Is marking active?
+  // Note: value is loaded for test purposes only. No further use here.
+  if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
+    load_and_test_int(Rtmp1, Address(Z_thread, active_offset));
+  } else {
+    guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "Assumption");
+    load_and_test_byte(Rtmp1, Address(Z_thread, active_offset));
+  }
+  z_bre(filtered); // Activity indicator is zero, so there is no marking going on currently.
+
+  // Do we need to load the previous value into Rpre_val?
+  if (Robj != noreg) {
+    // Load the previous value...
+    Register ixReg = offset.is_register() ? offset.register_or_noreg() : Z_R0;
+    if (UseCompressedOops) {
+      z_llgf(Rpre_val, offset.constant_or_zero(), ixReg, Robj);
+    } else {
+      z_lg(Rpre_val, offset.constant_or_zero(), ixReg, Robj);
+    }
+  }
+  assert(Rpre_val != noreg, "must have a real register");
+
+  // Is the previous value NULL?
+  // Note: pre_val is loaded, decompressed and stored (directly or via runtime call).
+  //       Register contents is preserved across runtime call if caller requests to do so.
+  z_ltgr(Rpre_val, Rpre_val);
+  z_bre(filtered); // previous value is NULL, so we don't need to record it.
+
+  // Decode the oop now. We know it's not NULL.
+  if (Robj != noreg && UseCompressedOops) {
+    oop_decoder(Rpre_val, Rpre_val, /*maybeNULL=*/false);
+  }
+
+  // OK, it's not filtered, so we'll need to call enqueue.
+
+  // We can store the original value in the thread's buffer
+  // only if index > 0. Otherwise, we need runtime to handle.
+  // (The index field is typed as size_t.)
+  Register Rbuffer = Rtmp1, Rindex = Rtmp2;
+
+  z_lg(Rbuffer, buffer_offset, Z_thread);
+
+  load_and_test_long(Rindex, Address(Z_thread, index_offset));
+  z_bre(callRuntime); // If index == 0, goto runtime.
+
+  add2reg(Rindex, -wordSize); // Decrement index.
+  z_stg(Rindex, index_offset, Z_thread);
+
+  // Record the previous value.
+  z_stg(Rpre_val, 0, Rbuffer, Rindex);
+  z_bru(filtered);  // We are done.
+
+  Rbuffer = noreg;  // end of life
+  Rindex  = noreg;  // end of life
+
+  bind(callRuntime);
+
+  // Save Rpre_val (result) over runtime call.
+  // Requires Rtmp1, Rtmp2, or Rpre_val to be non-volatile.
+  Register Rpre_save = Rpre_val;
+  if (pre_val_needed && Rpre_val->is_volatile()) {
+    guarantee(!Rtmp1->is_volatile() || !Rtmp2->is_volatile(), "oops!");
+    Rpre_save = !Rtmp1->is_volatile() ? Rtmp1 : Rtmp2;
+  }
+  lgr_if_needed(Rpre_save, Rpre_val);
+
+  // Preserve inputs by spilling them into the top frame.
+  if (Robj != noreg && Robj->is_volatile()) {
+    z_stg(Robj, Robj->encoding()*BytesPerWord, Z_SP);
+  }
+  if (offset.is_register() && offset.as_register()->is_volatile()) {
+    Register Roff = offset.as_register();
+    z_stg(Roff, Roff->encoding()*BytesPerWord, Z_SP);
+  }
+  if (Rval != noreg && Rval->is_volatile()) {
+    z_stg(Rval, Rval->encoding()*BytesPerWord, Z_SP);
+  }
+
+  // Push frame to protect top frame with return pc and spilled register values.
+  save_return_pc();
+  push_frame_abi160(0); // Will use Z_R0 as tmp on old CPUs.
+
+  call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), Rpre_val, Z_thread);
+
+  pop_frame();
+  restore_return_pc();
+
+  // Restore spilled values.
+  if (Robj != noreg && Robj->is_volatile()) {
+    z_lg(Robj, Robj->encoding()*BytesPerWord, Z_SP);
+  }
+  if (offset.is_register() && offset.as_register()->is_volatile()) {
+    Register Roff = offset.as_register();
+    z_lg(Roff, Roff->encoding()*BytesPerWord, Z_SP);
+  }
+  if (Rval != noreg && Rval->is_volatile()) {
+    z_lg(Rval, Rval->encoding()*BytesPerWord, Z_SP);
+  }
+
+  // Restore Rpre_val (result) after runtime call.
+  lgr_if_needed(Rpre_val, Rpre_save);
+
+  bind(filtered);
+  BLOCK_COMMENT("} g1_write_barrier_pre");
+}
+
+// General G1 post-barrier generator.
+// Purpose: Store cross-region card.
+void MacroAssembler::g1_write_barrier_post(Register Rstore_addr,
+                                           Register Rnew_val,
+                                           Register Rtmp1,
+                                           Register Rtmp2,
+                                           Register Rtmp3) {
+  Label callRuntime, filtered;
+
+  assert_different_registers(Rstore_addr, Rnew_val, Rtmp1, Rtmp2); // Most probably, Rnew_val == Rtmp3.
+
+  G1SATBCardTableModRefBS* bs = (G1SATBCardTableModRefBS*) Universe::heap()->barrier_set();
+  assert(bs->kind() == BarrierSet::G1SATBCTLogging, "wrong barrier");
+
+  BLOCK_COMMENT("g1_write_barrier_post {");
+
+  // Does store cross heap regions?
+  // It does if the two addresses specify different grain addresses.
+  if (G1RSBarrierRegionFilter) {
+    if (VM_Version::has_DistinctOpnds()) {
+      z_xgrk(Rtmp1, Rstore_addr, Rnew_val);
+    } else {
+      z_lgr(Rtmp1, Rstore_addr);
+      z_xgr(Rtmp1, Rnew_val);
+    }
+    z_srag(Rtmp1, Rtmp1, HeapRegion::LogOfHRGrainBytes);
+    z_bre(filtered);
+  }
+
+  // Crosses regions, storing NULL?
+#ifdef ASSERT
+  z_ltgr(Rnew_val, Rnew_val);
+  asm_assert_ne("null oop not allowed (G1)", 0x255); // TODO: also on z? Checked by caller on PPC64, so following branch is obsolete:
+  z_bre(filtered);  // Safety net: don't break if we have a NULL oop.
+#endif
+  Rnew_val = noreg; // end of lifetime
+
+  // Storing region crossing non-NULL, is card already dirty?
+  assert(sizeof(*bs->byte_map_base) == sizeof(jbyte), "adjust this code");
+  assert_different_registers(Rtmp1, Rtmp2, Rtmp3);
+  // Make sure not to use Z_R0 for any of these registers.
+  Register Rcard_addr = (Rtmp1 != Z_R0_scratch) ? Rtmp1 : Rtmp3;
+  Register Rbase      = (Rtmp2 != Z_R0_scratch) ? Rtmp2 : Rtmp3;
+
+  // calculate address of card
+  load_const_optimized(Rbase, (address)bs->byte_map_base);        // Card table base.
+  z_srlg(Rcard_addr, Rstore_addr, CardTableModRefBS::card_shift); // Index into card table.
+  add2reg_with_index(Rcard_addr, 0, Rcard_addr, Rbase);           // Explicit calculation needed for cli.
+  Rbase = noreg; // end of lifetime
+
+  // Filter young.
+  assert((unsigned int)G1SATBCardTableModRefBS::g1_young_card_val() <= 255, "otherwise check this code");
+  z_cli(0, Rcard_addr, (int)G1SATBCardTableModRefBS::g1_young_card_val());
+  z_bre(filtered);
+
+  // Check the card value. If dirty, we're done.
+  // This also avoids false sharing of the (already dirty) card.
+  z_sync(); // Required to support concurrent cleaning.
+  assert((unsigned int)CardTableModRefBS::dirty_card_val() <= 255, "otherwise check this code");
+  z_cli(0, Rcard_addr, CardTableModRefBS::dirty_card_val()); // Reload after membar.
+  z_bre(filtered);
+
+  // Storing a region crossing, non-NULL oop, card is clean.
+  // Dirty card and log.
+  z_mvi(0, Rcard_addr, CardTableModRefBS::dirty_card_val());
+
+  Register Rcard_addr_x = Rcard_addr;
+  Register Rqueue_index = (Rtmp2 != Z_R0_scratch) ? Rtmp2 : Rtmp1;
+  Register Rqueue_buf   = (Rtmp3 != Z_R0_scratch) ? Rtmp3 : Rtmp1;
+  const int qidx_off    = in_bytes(JavaThread::dirty_card_queue_offset() + SATBMarkQueue::byte_offset_of_index());
+  const int qbuf_off    = in_bytes(JavaThread::dirty_card_queue_offset() + SATBMarkQueue::byte_offset_of_buf());
+  if ((Rcard_addr == Rqueue_buf) || (Rcard_addr == Rqueue_index)) {
+    Rcard_addr_x = Z_R0_scratch;  // Register shortage. We have to use Z_R0.
+  }
+  lgr_if_needed(Rcard_addr_x, Rcard_addr);
+
+  load_and_test_long(Rqueue_index, Address(Z_thread, qidx_off));
+  z_bre(callRuntime); // Index == 0 then jump to runtime.
+
+  z_lg(Rqueue_buf, qbuf_off, Z_thread);
+
+  add2reg(Rqueue_index, -wordSize); // Decrement index.
+  z_stg(Rqueue_index, qidx_off, Z_thread);
+
+  z_stg(Rcard_addr_x, 0, Rqueue_index, Rqueue_buf); // Store card.
+  z_bru(filtered);
+
+  bind(callRuntime);
+
+  // TODO: do we need a frame? Introduced to be on the safe side.
+  bool needs_frame = true;
+
+  // VM call need frame to access(write) O register.
+  if (needs_frame) {
+    save_return_pc();
+    push_frame_abi160(0); // Will use Z_R0 as tmp on old CPUs.
+  }
+
+  // Save the live input values.
+  call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), Rcard_addr_x, Z_thread);
+
+  if (needs_frame) {
+    pop_frame();
+    restore_return_pc();
+  }
+
+  bind(filtered);
+
+  BLOCK_COMMENT("} g1_write_barrier_post");
+}
+#endif // INCLUDE_ALL_GCS
+
+// Last_Java_sp must comply to the rules in frame_s390.hpp.
+void MacroAssembler::set_last_Java_frame(Register last_Java_sp, Register last_Java_pc, bool allow_relocation) {
+  BLOCK_COMMENT("set_last_Java_frame {");
+
+  // Always set last_Java_pc and flags first because once last_Java_sp
+  // is visible has_last_Java_frame is true and users will look at the
+  // rest of the fields. (Note: flags should always be zero before we
+  // get here so doesn't need to be set.)
+
+  // Verify that last_Java_pc was zeroed on return to Java.
+  if (allow_relocation) {
+    asm_assert_mem8_is_zero(in_bytes(JavaThread::last_Java_pc_offset()),
+                            Z_thread,
+                            "last_Java_pc not zeroed before leaving Java",
+                            0x200);
+  } else {
+    asm_assert_mem8_is_zero_static(in_bytes(JavaThread::last_Java_pc_offset()),
+                                   Z_thread,
+                                   "last_Java_pc not zeroed before leaving Java",
+                                   0x200);
+  }
+
+  // When returning from calling out from Java mode the frame anchor's
+  // last_Java_pc will always be set to NULL. It is set here so that
+  // if we are doing a call to native (not VM) that we capture the
+  // known pc and don't have to rely on the native call having a
+  // standard frame linkage where we can find the pc.
+  if (last_Java_pc!=noreg) {
+    z_stg(last_Java_pc, Address(Z_thread, JavaThread::last_Java_pc_offset()));
+  }
+
+  // This membar release is not required on z/Architecture, since the sequence of stores
+  // in maintained. Nevertheless, we leave it in to document the required ordering.
+  // The implementation of z_release() should be empty.
+  // z_release();
+
+  z_stg(last_Java_sp, Address(Z_thread, JavaThread::last_Java_sp_offset()));
+  BLOCK_COMMENT("} set_last_Java_frame");
+}
+
+void MacroAssembler::reset_last_Java_frame(bool allow_relocation) {
+  BLOCK_COMMENT("reset_last_Java_frame {");
+
+  if (allow_relocation) {
+    asm_assert_mem8_isnot_zero(in_bytes(JavaThread::last_Java_sp_offset()),
+                               Z_thread,
+                               "SP was not set, still zero",
+                               0x202);
+  } else {
+    asm_assert_mem8_isnot_zero_static(in_bytes(JavaThread::last_Java_sp_offset()),
+                                      Z_thread,
+                                      "SP was not set, still zero",
+                                      0x202);
+  }
+
+  // _last_Java_sp = 0
+  // Clearing storage must be atomic here, so don't use clear_mem()!
+  store_const(Address(Z_thread, JavaThread::last_Java_sp_offset()), 0);
+
+  // _last_Java_pc = 0
+  store_const(Address(Z_thread, JavaThread::last_Java_pc_offset()), 0);
+
+  BLOCK_COMMENT("} reset_last_Java_frame");
+  return;
+}
+
+void MacroAssembler::set_top_ijava_frame_at_SP_as_last_Java_frame(Register sp, Register tmp1, bool allow_relocation) {
+  assert_different_registers(sp, tmp1);
+
+  // We cannot trust that code generated by the C++ compiler saves R14
+  // to z_abi_160.return_pc, because sometimes it spills R14 using stmg at
+  // z_abi_160.gpr14 (e.g. InterpreterRuntime::_new()).
+  // Therefore we load the PC into tmp1 and let set_last_Java_frame() save
+  // it into the frame anchor.
+  get_PC(tmp1);
+  set_last_Java_frame(/*sp=*/sp, /*pc=*/tmp1, allow_relocation);
+}
+
+void MacroAssembler::set_thread_state(JavaThreadState new_state) {
+  z_release();
+
+  assert(Immediate::is_uimm16(_thread_max_state), "enum value out of range for instruction");
+  assert(sizeof(JavaThreadState) == sizeof(int), "enum value must have base type int");
+  store_const(Address(Z_thread, JavaThread::thread_state_offset()), new_state, Z_R0, false);
+}
+
+void MacroAssembler::get_vm_result(Register oop_result) {
+  verify_thread();
+
+  z_lg(oop_result, Address(Z_thread, JavaThread::vm_result_offset()));
+  clear_mem(Address(Z_thread, JavaThread::vm_result_offset()), sizeof(void*));
+
+  verify_oop(oop_result);
+}
+
+void MacroAssembler::get_vm_result_2(Register result) {
+  verify_thread();
+
+  z_lg(result, Address(Z_thread, JavaThread::vm_result_2_offset()));
+  clear_mem(Address(Z_thread, JavaThread::vm_result_2_offset()), sizeof(void*));
+}
+
+// We require that C code which does not return a value in vm_result will
+// leave it undisturbed.
+void MacroAssembler::set_vm_result(Register oop_result) {
+  z_stg(oop_result, Address(Z_thread, JavaThread::vm_result_offset()));
+}
+
+// Explicit null checks (used for method handle code).
+void MacroAssembler::null_check(Register reg, Register tmp, int64_t offset) {
+  if (!ImplicitNullChecks) {
+    NearLabel ok;
+
+    compare64_and_branch(reg, (intptr_t) 0, Assembler::bcondNotEqual, ok);
+
+    // We just put the address into reg if it was 0 (tmp==Z_R0 is allowed so we can't use it for the address).
+    address exception_entry = Interpreter::throw_NullPointerException_entry();
+    load_absolute_address(reg, exception_entry);
+    z_br(reg);
+
+    bind(ok);
+  } else {
+    if (needs_explicit_null_check((intptr_t)offset)) {
+      // Provoke OS NULL exception if reg = NULL by
+      // accessing M[reg] w/o changing any registers.
+      z_lg(tmp, 0, reg);
+    }
+    // else
+      // Nothing to do, (later) access of M[reg + offset]
+      // will provoke OS NULL exception if reg = NULL.
+  }
+}
+
+//-------------------------------------
+//  Compressed Klass Pointers
+//-------------------------------------
+
+// Klass oop manipulations if compressed.
+void MacroAssembler::encode_klass_not_null(Register dst, Register src) {
+  Register current = (src != noreg) ? src : dst; // Klass is in dst if no src provided. (dst == src) also possible.
+  address  base    = Universe::narrow_klass_base();
+  int      shift   = Universe::narrow_klass_shift();
+  assert(UseCompressedClassPointers, "only for compressed klass ptrs");
+
+  BLOCK_COMMENT("cKlass encoder {");
+
+#ifdef ASSERT
+  Label ok;
+  z_tmll(current, KlassAlignmentInBytes-1); // Check alignment.
+  z_brc(Assembler::bcondAllZero, ok);
+  // The plain disassembler does not recognize illtrap. It instead displays
+  // a 32-bit value. Issueing two illtraps assures the disassembler finds
+  // the proper beginning of the next instruction.
+  z_illtrap(0xee);
+  z_illtrap(0xee);
+  bind(ok);
+#endif
+
+  if (base != NULL) {
+    unsigned int base_h = ((unsigned long)base)>>32;
+    unsigned int base_l = (unsigned int)((unsigned long)base);
+    if ((base_h != 0) && (base_l == 0) && VM_Version::has_HighWordInstr()) {
+      lgr_if_needed(dst, current);
+      z_aih(dst, -((int)base_h));     // Base has no set bits in lower half.
+    } else if ((base_h == 0) && (base_l != 0)) {
+      lgr_if_needed(dst, current);
+      z_agfi(dst, -(int)base_l);
+    } else {
+      load_const(Z_R0, base);
+      lgr_if_needed(dst, current);
+      z_sgr(dst, Z_R0);
+    }
+    current = dst;
+  }
+  if (shift != 0) {
+    assert (LogKlassAlignmentInBytes == shift, "decode alg wrong");
+    z_srlg(dst, current, shift);
+    current = dst;
+  }
+  lgr_if_needed(dst, current); // Move may be required (if neither base nor shift != 0).
+
+  BLOCK_COMMENT("} cKlass encoder");
+}
+
+// This function calculates the size of the code generated by
+//   decode_klass_not_null(register dst, Register src)
+// when (Universe::heap() != NULL). Hence, if the instructions
+// it generates change, then this method needs to be updated.
+int MacroAssembler::instr_size_for_decode_klass_not_null() {
+  address  base    = Universe::narrow_klass_base();
+  int shift_size   = Universe::narrow_klass_shift() == 0 ? 0 : 6; /* sllg */
+  int addbase_size = 0;
+  assert(UseCompressedClassPointers, "only for compressed klass ptrs");
+
+  if (base != NULL) {
+    unsigned int base_h = ((unsigned long)base)>>32;
+    unsigned int base_l = (unsigned int)((unsigned long)base);
+    if ((base_h != 0) && (base_l == 0) && VM_Version::has_HighWordInstr()) {
+      addbase_size += 6; /* aih */
+    } else if ((base_h == 0) && (base_l != 0)) {
+      addbase_size += 6; /* algfi */
+    } else {
+      addbase_size += load_const_size();
+      addbase_size += 4; /* algr */
+    }
+  }
+#ifdef ASSERT
+  addbase_size += 10;
+  addbase_size += 2; // Extra sigill.
+#endif
+  return addbase_size + shift_size;
+}
+
+// !!! If the instructions that get generated here change
+//     then function instr_size_for_decode_klass_not_null()
+//     needs to get updated.
+// This variant of decode_klass_not_null() must generate predictable code!
+// The code must only depend on globally known parameters.
+void MacroAssembler::decode_klass_not_null(Register dst) {
+  address  base    = Universe::narrow_klass_base();
+  int      shift   = Universe::narrow_klass_shift();
+  int      beg_off = offset();
+  assert(UseCompressedClassPointers, "only for compressed klass ptrs");
+
+  BLOCK_COMMENT("cKlass decoder (const size) {");
+
+  if (shift != 0) { // Shift required?
+    z_sllg(dst, dst, shift);
+  }
+  if (base != NULL) {
+    unsigned int base_h = ((unsigned long)base)>>32;
+    unsigned int base_l = (unsigned int)((unsigned long)base);
+    if ((base_h != 0) && (base_l == 0) && VM_Version::has_HighWordInstr()) {
+      z_aih(dst, base_h);     // Base has no set bits in lower half.
+    } else if ((base_h == 0) && (base_l != 0)) {
+      z_algfi(dst, base_l);   // Base has no set bits in upper half.
+    } else {
+      load_const(Z_R0, base); // Base has set bits everywhere.
+      z_algr(dst, Z_R0);
+    }
+  }
+
+#ifdef ASSERT
+  Label ok;
+  z_tmll(dst, KlassAlignmentInBytes-1); // Check alignment.
+  z_brc(Assembler::bcondAllZero, ok);
+  // The plain disassembler does not recognize illtrap. It instead displays
+  // a 32-bit value. Issueing two illtraps assures the disassembler finds
+  // the proper beginning of the next instruction.
+  z_illtrap(0xd1);
+  z_illtrap(0xd1);
+  bind(ok);
+#endif
+  assert(offset() == beg_off + instr_size_for_decode_klass_not_null(), "Code gen mismatch.");
+
+  BLOCK_COMMENT("} cKlass decoder (const size)");
+}
+
+// This variant of decode_klass_not_null() is for cases where
+//  1) the size of the generated instructions may vary
+//  2) the result is (potentially) stored in a register different from the source.
+void MacroAssembler::decode_klass_not_null(Register dst, Register src) {
+  address base  = Universe::narrow_klass_base();
+  int     shift = Universe::narrow_klass_shift();
+  assert(UseCompressedClassPointers, "only for compressed klass ptrs");
+
+  BLOCK_COMMENT("cKlass decoder {");
+
+  if (src == noreg) src = dst;
+
+  if (shift != 0) { // Shift or at least move required?
+    z_sllg(dst, src, shift);
+  } else {
+    lgr_if_needed(dst, src);
+  }
+
+  if (base != NULL) {
+    unsigned int base_h = ((unsigned long)base)>>32;
+    unsigned int base_l = (unsigned int)((unsigned long)base);
+    if ((base_h != 0) && (base_l == 0) && VM_Version::has_HighWordInstr()) {
+      z_aih(dst, base_h);     // Base has not set bits in lower half.
+    } else if ((base_h == 0) && (base_l != 0)) {
+      z_algfi(dst, base_l);   // Base has no set bits in upper half.
+    } else {
+      load_const_optimized(Z_R0, base); // Base has set bits everywhere.
+      z_algr(dst, Z_R0);
+    }
+  }
+
+#ifdef ASSERT
+  Label ok;
+  z_tmll(dst, KlassAlignmentInBytes-1); // Check alignment.
+  z_brc(Assembler::bcondAllZero, ok);
+  // The plain disassembler does not recognize illtrap. It instead displays
+  // a 32-bit value. Issueing two illtraps assures the disassembler finds
+  // the proper beginning of the next instruction.
+  z_illtrap(0xd2);
+  z_illtrap(0xd2);
+  bind(ok);
+#endif
+  BLOCK_COMMENT("} cKlass decoder");
+}
+
+void MacroAssembler::load_klass(Register klass, Address mem) {
+  if (UseCompressedClassPointers) {
+    z_llgf(klass, mem);
+    // Attention: no null check here!
+    decode_klass_not_null(klass);
+  } else {
+    z_lg(klass, mem);
+  }
+}
+
+void MacroAssembler::load_klass(Register klass, Register src_oop) {
+  if (UseCompressedClassPointers) {
+    z_llgf(klass, oopDesc::klass_offset_in_bytes(), src_oop);
+    // Attention: no null check here!
+    decode_klass_not_null(klass);
+  } else {
+    z_lg(klass, oopDesc::klass_offset_in_bytes(), src_oop);
+  }
+}
+
+void MacroAssembler::load_prototype_header(Register Rheader, Register Rsrc_oop) {
+  assert_different_registers(Rheader, Rsrc_oop);
+  load_klass(Rheader, Rsrc_oop);
+  z_lg(Rheader, Address(Rheader, Klass::prototype_header_offset()));
+}
+
+void MacroAssembler::store_klass(Register klass, Register dst_oop, Register ck) {
+  if (UseCompressedClassPointers) {
+    assert_different_registers(dst_oop, klass, Z_R0);
+    if (ck == noreg) ck = klass;
+    encode_klass_not_null(ck, klass);
+    z_st(ck, Address(dst_oop, oopDesc::klass_offset_in_bytes()));
+  } else {
+    z_stg(klass, Address(dst_oop, oopDesc::klass_offset_in_bytes()));
+  }
+}
+
+void MacroAssembler::store_klass_gap(Register s, Register d) {
+  if (UseCompressedClassPointers) {
+    assert(s != d, "not enough registers");
+    z_st(s, Address(d, oopDesc::klass_gap_offset_in_bytes()));
+  }
+}
+
+// Compare klass ptr in memory against klass ptr in register.
+//
+// Rop1            - klass in register, always uncompressed.
+// disp            - Offset of klass in memory, compressed/uncompressed, depending on runtime flag.
+// Rbase           - Base address of cKlass in memory.
+// maybeNULL       - True if Rop1 possibly is a NULL.
+void MacroAssembler::compare_klass_ptr(Register Rop1, int64_t disp, Register Rbase, bool maybeNULL) {
+
+  BLOCK_COMMENT("compare klass ptr {");
+
+  if (UseCompressedClassPointers) {
+    const int shift = Universe::narrow_klass_shift();
+    address   base  = Universe::narrow_klass_base();
+
+    assert((shift == 0) || (shift == LogKlassAlignmentInBytes), "cKlass encoder detected bad shift");
+    assert_different_registers(Rop1, Z_R0);
+    assert_different_registers(Rop1, Rbase, Z_R1);
+
+    // First encode register oop and then compare with cOop in memory.
+    // This sequence saves an unnecessary cOop load and decode.
+    if (base == NULL) {
+      if (shift == 0) {
+        z_cl(Rop1, disp, Rbase);     // Unscaled
+      } else {
+        z_srlg(Z_R0, Rop1, shift);   // ZeroBased
+        z_cl(Z_R0, disp, Rbase);
+      }
+    } else {                         // HeapBased
+#ifdef ASSERT
+      bool     used_R0 = true;
+      bool     used_R1 = true;
+#endif
+      Register current = Rop1;
+      Label    done;
+
+      if (maybeNULL) {       // NULL ptr must be preserved!
+        z_ltgr(Z_R0, current);
+        z_bre(done);
+        current = Z_R0;
+      }
+
+      unsigned int base_h = ((unsigned long)base)>>32;
+      unsigned int base_l = (unsigned int)((unsigned long)base);
+      if ((base_h != 0) && (base_l == 0) && VM_Version::has_HighWordInstr()) {
+        lgr_if_needed(Z_R0, current);
+        z_aih(Z_R0, -((int)base_h));     // Base has no set bits in lower half.
+      } else if ((base_h == 0) && (base_l != 0)) {
+        lgr_if_needed(Z_R0, current);
+        z_agfi(Z_R0, -(int)base_l);
+      } else {
+        int pow2_offset = get_oop_base_complement(Z_R1, ((uint64_t)(intptr_t)base));
+        add2reg_with_index(Z_R0, pow2_offset, Z_R1, Rop1); // Subtract base by adding complement.
+      }
+
+      if (shift != 0) {
+        z_srlg(Z_R0, Z_R0, shift);
+      }
+      bind(done);
+      z_cl(Z_R0, disp, Rbase);
+#ifdef ASSERT
+      if (used_R0) preset_reg(Z_R0, 0xb05bUL, 2);
+      if (used_R1) preset_reg(Z_R1, 0xb06bUL, 2);
+#endif
+    }
+  } else {
+    z_clg(Rop1, disp, Z_R0, Rbase);
+  }
+  BLOCK_COMMENT("} compare klass ptr");
+}
+
+//---------------------------
+//  Compressed oops
+//---------------------------
+
+void MacroAssembler::encode_heap_oop(Register oop) {
+  oop_encoder(oop, oop, true /*maybe null*/);
+}
+
+void MacroAssembler::encode_heap_oop_not_null(Register oop) {
+  oop_encoder(oop, oop, false /*not null*/);
+}
+
+// Called with something derived from the oop base. e.g. oop_base>>3.
+int MacroAssembler::get_oop_base_pow2_offset(uint64_t oop_base) {
+  unsigned int oop_base_ll = ((unsigned int)(oop_base >>  0)) & 0xffff;
+  unsigned int oop_base_lh = ((unsigned int)(oop_base >> 16)) & 0xffff;
+  unsigned int oop_base_hl = ((unsigned int)(oop_base >> 32)) & 0xffff;
+  unsigned int oop_base_hh = ((unsigned int)(oop_base >> 48)) & 0xffff;
+  unsigned int n_notzero_parts = (oop_base_ll == 0 ? 0:1)
+                               + (oop_base_lh == 0 ? 0:1)
+                               + (oop_base_hl == 0 ? 0:1)
+                               + (oop_base_hh == 0 ? 0:1);
+
+  assert(oop_base != 0, "This is for HeapBased cOops only");
+
+  if (n_notzero_parts != 1) { //  Check if oop_base is just a few pages shy of a power of 2.
+    uint64_t pow2_offset = 0x10000 - oop_base_ll;
+    if (pow2_offset < 0x8000) {  // This might not be necessary.
+      uint64_t oop_base2 = oop_base + pow2_offset;
+
+      oop_base_ll = ((unsigned int)(oop_base2 >>  0)) & 0xffff;
+      oop_base_lh = ((unsigned int)(oop_base2 >> 16)) & 0xffff;
+      oop_base_hl = ((unsigned int)(oop_base2 >> 32)) & 0xffff;
+      oop_base_hh = ((unsigned int)(oop_base2 >> 48)) & 0xffff;
+      n_notzero_parts = (oop_base_ll == 0 ? 0:1) +
+                        (oop_base_lh == 0 ? 0:1) +
+                        (oop_base_hl == 0 ? 0:1) +
+                        (oop_base_hh == 0 ? 0:1);
+      if (n_notzero_parts == 1) {
+        assert(-(int64_t)pow2_offset != (int64_t)-1, "We use -1 to signal uninitialized base register");
+        return -pow2_offset;
+      }
+    }
+  }
+  return 0;
+}
+
+// If base address is offset from a straight power of two by just a few pages,
+// return this offset to the caller for a possible later composite add.
+// TODO/FIX: will only work correctly for 4k pages.
+int MacroAssembler::get_oop_base(Register Rbase, uint64_t oop_base) {
+  int pow2_offset = get_oop_base_pow2_offset(oop_base);
+
+  load_const_optimized(Rbase, oop_base - pow2_offset); // Best job possible.
+
+  return pow2_offset;
+}
+
+int MacroAssembler::get_oop_base_complement(Register Rbase, uint64_t oop_base) {
+  int offset = get_oop_base(Rbase, oop_base);
+  z_lcgr(Rbase, Rbase);
+  return -offset;
+}
+
+// Compare compressed oop in memory against oop in register.
+// Rop1            - Oop in register.
+// disp            - Offset of cOop in memory.
+// Rbase           - Base address of cOop in memory.
+// maybeNULL       - True if Rop1 possibly is a NULL.
+// maybeNULLtarget - Branch target for Rop1 == NULL, if flow control shall NOT continue with compare instruction.
+void MacroAssembler::compare_heap_oop(Register Rop1, Address mem, bool maybeNULL) {
+  Register Rbase  = mem.baseOrR0();
+  Register Rindex = mem.indexOrR0();
+  int64_t  disp   = mem.disp();
+
+  const int shift = Universe::narrow_oop_shift();
+  address   base  = Universe::narrow_oop_base();
+
+  assert(UseCompressedOops, "must be on to call this method");
+  assert(Universe::heap() != NULL, "java heap must be initialized to call this method");
+  assert((shift == 0) || (shift == LogMinObjAlignmentInBytes), "cOop encoder detected bad shift");
+  assert_different_registers(Rop1, Z_R0);
+  assert_different_registers(Rop1, Rbase, Z_R1);
+  assert_different_registers(Rop1, Rindex, Z_R1);
+
+  BLOCK_COMMENT("compare heap oop {");
+
+  // First encode register oop and then compare with cOop in memory.
+  // This sequence saves an unnecessary cOop load and decode.
+  if (base == NULL) {
+    if (shift == 0) {
+      z_cl(Rop1, disp, Rindex, Rbase);  // Unscaled
+    } else {
+      z_srlg(Z_R0, Rop1, shift);        // ZeroBased
+      z_cl(Z_R0, disp, Rindex, Rbase);
+    }
+  } else {                              // HeapBased
+#ifdef ASSERT
+    bool  used_R0 = true;
+    bool  used_R1 = true;
+#endif
+    Label done;
+    int   pow2_offset = get_oop_base_complement(Z_R1, ((uint64_t)(intptr_t)base));
+
+    if (maybeNULL) {       // NULL ptr must be preserved!
+      z_ltgr(Z_R0, Rop1);
+      z_bre(done);
+    }
+
+    add2reg_with_index(Z_R0, pow2_offset, Z_R1, Rop1);
+    z_srlg(Z_R0, Z_R0, shift);
+
+    bind(done);
+    z_cl(Z_R0, disp, Rindex, Rbase);
+#ifdef ASSERT
+    if (used_R0) preset_reg(Z_R0, 0xb05bUL, 2);
+    if (used_R1) preset_reg(Z_R1, 0xb06bUL, 2);
+#endif
+  }
+  BLOCK_COMMENT("} compare heap oop");
+}
+
+// Load heap oop and decompress, if necessary.
+void  MacroAssembler::load_heap_oop(Register dest, const Address &a) {
+  if (UseCompressedOops) {
+    z_llgf(dest, a.disp(), a.indexOrR0(), a.baseOrR0());
+    oop_decoder(dest, dest, true);
+  } else {
+    z_lg(dest, a.disp(), a.indexOrR0(), a.baseOrR0());
+  }
+}
+
+// Load heap oop and decompress, if necessary.
+void MacroAssembler::load_heap_oop(Register dest, int64_t disp, Register base) {
+  if (UseCompressedOops) {
+    z_llgf(dest, disp, base);
+    oop_decoder(dest, dest, true);
+  } else {
+    z_lg(dest, disp, base);
+  }
+}
+
+// Load heap oop and decompress, if necessary.
+void MacroAssembler::load_heap_oop_not_null(Register dest, int64_t disp, Register base) {
+  if (UseCompressedOops) {
+    z_llgf(dest, disp, base);
+    oop_decoder(dest, dest, false);
+  } else {
+    z_lg(dest, disp, base);
+  }
+}
+
+// Compress, if necessary, and store oop to heap.
+void MacroAssembler::store_heap_oop(Register Roop, RegisterOrConstant offset, Register base) {
+  Register Ridx = offset.is_register() ? offset.register_or_noreg() : Z_R0;
+  if (UseCompressedOops) {
+    assert_different_registers(Roop, offset.register_or_noreg(), base);
+    encode_heap_oop(Roop);
+    z_st(Roop, offset.constant_or_zero(), Ridx, base);
+  } else {
+    z_stg(Roop, offset.constant_or_zero(), Ridx, base);
+  }
+}
+
+// Compress, if necessary, and store oop to heap. Oop is guaranteed to be not NULL.
+void MacroAssembler::store_heap_oop_not_null(Register Roop, RegisterOrConstant offset, Register base) {
+  Register Ridx = offset.is_register() ? offset.register_or_noreg() : Z_R0;
+  if (UseCompressedOops) {
+    assert_different_registers(Roop, offset.register_or_noreg(), base);
+    encode_heap_oop_not_null(Roop);
+    z_st(Roop, offset.constant_or_zero(), Ridx, base);
+  } else {
+    z_stg(Roop, offset.constant_or_zero(), Ridx, base);
+  }
+}
+
+// Store NULL oop to heap.
+void MacroAssembler::store_heap_oop_null(Register zero, RegisterOrConstant offset, Register base) {
+  Register Ridx = offset.is_register() ? offset.register_or_noreg() : Z_R0;
+  if (UseCompressedOops) {
+    z_st(zero, offset.constant_or_zero(), Ridx, base);
+  } else {
+    z_stg(zero, offset.constant_or_zero(), Ridx, base);
+  }
+}
+
+//-------------------------------------------------
+// Encode compressed oop. Generally usable encoder.
+//-------------------------------------------------
+// Rsrc - contains regular oop on entry. It remains unchanged.
+// Rdst - contains compressed oop on exit.
+// Rdst and Rsrc may indicate same register, in which case Rsrc does not remain unchanged.
+//
+// Rdst must not indicate scratch register Z_R1 (Z_R1_scratch) for functionality.
+// Rdst should not indicate scratch register Z_R0 (Z_R0_scratch) for performance.
+//
+// only32bitValid is set, if later code only uses the lower 32 bits. In this
+// case we must not fix the upper 32 bits.
+void MacroAssembler::oop_encoder(Register Rdst, Register Rsrc, bool maybeNULL,
+                                 Register Rbase, int pow2_offset, bool only32bitValid) {
+
+  const address oop_base  = Universe::narrow_oop_base();
+  const int     oop_shift = Universe::narrow_oop_shift();
+  const bool    disjoint  = Universe::narrow_oop_base_disjoint();
+
+  assert(UseCompressedOops, "must be on to call this method");
+  assert(Universe::heap() != NULL, "java heap must be initialized to call this encoder");
+  assert((oop_shift == 0) || (oop_shift == LogMinObjAlignmentInBytes), "cOop encoder detected bad shift");
+
+  if (disjoint || (oop_base == NULL)) {
+    BLOCK_COMMENT("cOop encoder zeroBase {");
+    if (oop_shift == 0) {
+      if (oop_base != NULL && !only32bitValid) {
+        z_llgfr(Rdst, Rsrc); // Clear upper bits in case the register will be decoded again.
+      } else {
+        lgr_if_needed(Rdst, Rsrc);
+      }
+    } else {
+      z_srlg(Rdst, Rsrc, oop_shift);
+      if (oop_base != NULL && !only32bitValid) {
+        z_llgfr(Rdst, Rdst); // Clear upper bits in case the register will be decoded again.
+      }
+    }
+    BLOCK_COMMENT("} cOop encoder zeroBase");
+    return;
+  }
+
+  bool used_R0 = false;
+  bool used_R1 = false;
+
+  BLOCK_COMMENT("cOop encoder general {");
+  assert_different_registers(Rdst, Z_R1);
+  assert_different_registers(Rsrc, Rbase);
+  if (maybeNULL) {
+    Label done;
+    // We reorder shifting and subtracting, so that we can compare
+    // and shift in parallel:
+    //
+    // cycle 0:  potential LoadN, base = <const>
+    // cycle 1:  base = !base     dst = src >> 3,    cmp cr = (src != 0)
+    // cycle 2:  if (cr) br,      dst = dst + base + offset
+
+    // Get oop_base components.
+    if (pow2_offset == -1) {
+      if (Rdst == Rbase) {
+        if (Rdst == Z_R1 || Rsrc == Z_R1) {
+          Rbase = Z_R0;
+          used_R0 = true;
+        } else {
+          Rdst = Z_R1;
+          used_R1 = true;
+        }
+      }
+      if (Rbase == Z_R1) {
+        used_R1 = true;
+      }
+      pow2_offset = get_oop_base_complement(Rbase, ((uint64_t)(intptr_t)oop_base) >> oop_shift);
+    }
+    assert_different_registers(Rdst, Rbase);
+
+    // Check for NULL oop (must be left alone) and shift.
+    if (oop_shift != 0) {  // Shift out alignment bits
+      if (((intptr_t)oop_base&0xc000000000000000L) == 0L) { // We are sure: no single address will have the leftmost bit set.
+        z_srag(Rdst, Rsrc, oop_shift);  // Arithmetic shift sets the condition code.
+      } else {
+        z_srlg(Rdst, Rsrc, oop_shift);
+        z_ltgr(Rsrc, Rsrc);  // This is the recommended way of testing for zero.
+        // This probably is faster, as it does not write a register. No!
+        // z_cghi(Rsrc, 0);
+      }
+    } else {
+      z_ltgr(Rdst, Rsrc);   // Move NULL to result register.
+    }
+    z_bre(done);
+
+    // Subtract oop_base components.
+    if ((Rdst == Z_R0) || (Rbase == Z_R0)) {
+      z_algr(Rdst, Rbase);
+      if (pow2_offset != 0) { add2reg(Rdst, pow2_offset); }
+    } else {
+      add2reg_with_index(Rdst, pow2_offset, Rbase, Rdst);
+    }
+    if (!only32bitValid) {
+      z_llgfr(Rdst, Rdst); // Clear upper bits in case the register will be decoded again.
+    }
+    bind(done);
+
+  } else {  // not null
+    // Get oop_base components.
+    if (pow2_offset == -1) {
+      pow2_offset = get_oop_base_complement(Rbase, (uint64_t)(intptr_t)oop_base);
+    }
+
+    // Subtract oop_base components and shift.
+    if (Rdst == Z_R0 || Rsrc == Z_R0 || Rbase == Z_R0) {
+      // Don't use lay instruction.
+      if (Rdst == Rsrc) {
+        z_algr(Rdst, Rbase);
+      } else {
+        lgr_if_needed(Rdst, Rbase);
+        z_algr(Rdst, Rsrc);
+      }
+      if (pow2_offset != 0) add2reg(Rdst, pow2_offset);
+    } else {
+      add2reg_with_index(Rdst, pow2_offset, Rbase, Rsrc);
+    }
+    if (oop_shift != 0) {   // Shift out alignment bits.
+      z_srlg(Rdst, Rdst, oop_shift);
+    }
+    if (!only32bitValid) {
+      z_llgfr(Rdst, Rdst); // Clear upper bits in case the register will be decoded again.
+    }
+  }
+#ifdef ASSERT
+  if (used_R0 && Rdst != Z_R0 && Rsrc != Z_R0) { preset_reg(Z_R0, 0xb01bUL, 2); }
+  if (used_R1 && Rdst != Z_R1 && Rsrc != Z_R1) { preset_reg(Z_R1, 0xb02bUL, 2); }
+#endif
+  BLOCK_COMMENT("} cOop encoder general");
+}
+
+//-------------------------------------------------
+// decode compressed oop. Generally usable decoder.
+//-------------------------------------------------
+// Rsrc - contains compressed oop on entry.
+// Rdst - contains regular oop on exit.
+// Rdst and Rsrc may indicate same register.
+// Rdst must not be the same register as Rbase, if Rbase was preloaded (before call).
+// Rdst can be the same register as Rbase. Then, either Z_R0 or Z_R1 must be available as scratch.
+// Rbase - register to use for the base
+// pow2_offset - offset of base to nice value. If -1, base must be loaded.
+// For performance, it is good to
+//  - avoid Z_R0 for any of the argument registers.
+//  - keep Rdst and Rsrc distinct from Rbase. Rdst == Rsrc is ok for performance.
+//  - avoid Z_R1 for Rdst if Rdst == Rbase.
+void MacroAssembler::oop_decoder(Register Rdst, Register Rsrc, bool maybeNULL, Register Rbase, int pow2_offset) {
+
+  const address oop_base  = Universe::narrow_oop_base();
+  const int     oop_shift = Universe::narrow_oop_shift();
+  const bool    disjoint  = Universe::narrow_oop_base_disjoint();
+
+  assert(UseCompressedOops, "must be on to call this method");
+  assert(Universe::heap() != NULL, "java heap must be initialized to call this decoder");
+  assert((oop_shift == 0) || (oop_shift == LogMinObjAlignmentInBytes),
+         "cOop encoder detected bad shift");
+
+  // cOops are always loaded zero-extended from memory. No explicit zero-extension necessary.
+
+  if (oop_base != NULL) {
+    unsigned int oop_base_hl = ((unsigned int)((uint64_t)(intptr_t)oop_base >> 32)) & 0xffff;
+    unsigned int oop_base_hh = ((unsigned int)((uint64_t)(intptr_t)oop_base >> 48)) & 0xffff;
+    unsigned int oop_base_hf = ((unsigned int)((uint64_t)(intptr_t)oop_base >> 32)) & 0xFFFFffff;
+    if (disjoint && (oop_base_hl == 0 || oop_base_hh == 0)) {
+      BLOCK_COMMENT("cOop decoder disjointBase {");
+      // We do not need to load the base. Instead, we can install the upper bits
+      // with an OR instead of an ADD.
+      Label done;
+
+      // Rsrc contains a narrow oop. Thus we are sure the leftmost <oop_shift> bits will never be set.
+      if (maybeNULL) {  // NULL ptr must be preserved!
+        z_slag(Rdst, Rsrc, oop_shift);  // Arithmetic shift sets the condition code.
+        z_bre(done);
+      } else {
+        z_sllg(Rdst, Rsrc, oop_shift);  // Logical shift leaves condition code alone.
+      }
+      if ((oop_base_hl != 0) && (oop_base_hh != 0)) {
+        z_oihf(Rdst, oop_base_hf);
+      } else if (oop_base_hl != 0) {
+        z_oihl(Rdst, oop_base_hl);
+      } else {
+        assert(oop_base_hh != 0, "not heapbased mode");
+        z_oihh(Rdst, oop_base_hh);
+      }
+      bind(done);
+      BLOCK_COMMENT("} cOop decoder disjointBase");
+    } else {
+      BLOCK_COMMENT("cOop decoder general {");
+      // There are three decode steps:
+      //   scale oop offset (shift left)
+      //   get base (in reg) and pow2_offset (constant)
+      //   add base, pow2_offset, and oop offset
+      // The following register overlap situations may exist:
+      // Rdst == Rsrc,  Rbase any other
+      //   not a problem. Scaling in-place leaves Rbase undisturbed.
+      //   Loading Rbase does not impact the scaled offset.
+      // Rdst == Rbase, Rsrc  any other
+      //   scaling would destroy a possibly preloaded Rbase. Loading Rbase
+      //   would destroy the scaled offset.
+      //   Remedy: use Rdst_tmp if Rbase has been preloaded.
+      //           use Rbase_tmp if base has to be loaded.
+      // Rsrc == Rbase, Rdst  any other
+      //   Only possible without preloaded Rbase.
+      //   Loading Rbase does not destroy compressed oop because it was scaled into Rdst before.
+      // Rsrc == Rbase, Rdst == Rbase
+      //   Only possible without preloaded Rbase.
+      //   Loading Rbase would destroy compressed oop. Scaling in-place is ok.
+      //   Remedy: use Rbase_tmp.
+      //
+      Label    done;
+      Register Rdst_tmp       = Rdst;
+      Register Rbase_tmp      = Rbase;
+      bool     used_R0        = false;
+      bool     used_R1        = false;
+      bool     base_preloaded = pow2_offset >= 0;
+      guarantee(!(base_preloaded && (Rsrc == Rbase)), "Register clash, check caller");
+      assert(oop_shift != 0, "room for optimization");
+
+      // Check if we need to use scratch registers.
+      if (Rdst == Rbase) {
+        assert(!(((Rdst == Z_R0) && (Rsrc == Z_R1)) || ((Rdst == Z_R1) && (Rsrc == Z_R0))), "need a scratch reg");
+        if (Rdst != Rsrc) {
+          if (base_preloaded) { Rdst_tmp  = (Rdst == Z_R1) ? Z_R0 : Z_R1; }
+          else                { Rbase_tmp = (Rdst == Z_R1) ? Z_R0 : Z_R1; }
+        } else {
+          Rbase_tmp = (Rdst == Z_R1) ? Z_R0 : Z_R1;
+        }
+      }
+      if (base_preloaded) lgr_if_needed(Rbase_tmp, Rbase);
+
+      // Scale oop and check for NULL.
+      // Rsrc contains a narrow oop. Thus we are sure the leftmost <oop_shift> bits will never be set.
+      if (maybeNULL) {  // NULL ptr must be preserved!
+        z_slag(Rdst_tmp, Rsrc, oop_shift);  // Arithmetic shift sets the condition code.
+        z_bre(done);
+      } else {
+        z_sllg(Rdst_tmp, Rsrc, oop_shift);  // Logical shift leaves condition code alone.
+      }
+
+      // Get oop_base components.
+      if (!base_preloaded) {
+        pow2_offset = get_oop_base(Rbase_tmp, (uint64_t)(intptr_t)oop_base);
+      }
+
+      // Add up all components.
+      if ((Rbase_tmp == Z_R0) || (Rdst_tmp == Z_R0)) {
+        z_algr(Rdst_tmp, Rbase_tmp);
+        if (pow2_offset != 0) { add2reg(Rdst_tmp, pow2_offset); }
+      } else {
+        add2reg_with_index(Rdst_tmp, pow2_offset, Rbase_tmp, Rdst_tmp);
+      }
+
+      bind(done);
+      lgr_if_needed(Rdst, Rdst_tmp);
+#ifdef ASSERT
+      if (used_R0 && Rdst != Z_R0 && Rsrc != Z_R0) { preset_reg(Z_R0, 0xb03bUL, 2); }
+      if (used_R1 && Rdst != Z_R1 && Rsrc != Z_R1) { preset_reg(Z_R1, 0xb04bUL, 2); }
+#endif
+      BLOCK_COMMENT("} cOop decoder general");
+    }
+  } else {
+    BLOCK_COMMENT("cOop decoder zeroBase {");
+    if (oop_shift == 0) {
+      lgr_if_needed(Rdst, Rsrc);
+    } else {
+      z_sllg(Rdst, Rsrc, oop_shift);
+    }
+    BLOCK_COMMENT("} cOop decoder zeroBase");
+  }
+}
+
+void MacroAssembler::load_mirror(Register mirror, Register method) {
+  mem2reg_opt(mirror, Address(method, Method::const_offset()));
+  mem2reg_opt(mirror, Address(mirror, ConstMethod::constants_offset()));
+  mem2reg_opt(mirror, Address(mirror, ConstantPool::pool_holder_offset_in_bytes()));
+  mem2reg_opt(mirror, Address(mirror, Klass::java_mirror_offset()));
+}
+
+//---------------------------------------------------------------
+//---  Operations on arrays.
+//---------------------------------------------------------------
+
+// Compiler ensures base is doubleword aligned and cnt is #doublewords.
+// Emitter does not KILL cnt and base arguments, since they need to be copied to
+// work registers anyway.
+// Actually, only r0, r1, and r5 are killed.
+unsigned int MacroAssembler::Clear_Array(Register cnt_arg, Register base_pointer_arg, Register src_addr, Register src_len) {
+  // Src_addr is evenReg.
+  // Src_len is odd_Reg.
+
+  int      block_start = offset();
+  Register tmp_reg  = src_len; // Holds target instr addr for EX.
+  Register dst_len  = Z_R1;    // Holds dst len  for MVCLE.
+  Register dst_addr = Z_R0;    // Holds dst addr for MVCLE.
+
+  Label doXC, doMVCLE, done;
+
+  BLOCK_COMMENT("Clear_Array {");
+
+  // Check for zero len and convert to long.
+  z_ltgfr(src_len, cnt_arg);      // Remember casted value for doSTG case.
+  z_bre(done);                    // Nothing to do if len == 0.
+
+  // Prefetch data to be cleared.
+  if (VM_Version::has_Prefetch()) {
+    z_pfd(0x02,   0, Z_R0, base_pointer_arg);
+    z_pfd(0x02, 256, Z_R0, base_pointer_arg);
+  }
+
+  z_sllg(dst_len, src_len, 3);    // #bytes to clear.
+  z_cghi(src_len, 32);            // Check for len <= 256 bytes (<=32 DW).
+  z_brnh(doXC);                   // If so, use executed XC to clear.
+
+  // MVCLE: initialize long arrays (general case).
+  bind(doMVCLE);
+  z_lgr(dst_addr, base_pointer_arg);
+  clear_reg(src_len, true, false); // Src len of MVCLE is zero.
+
+  MacroAssembler::move_long_ext(dst_addr, src_addr, 0);
+  z_bru(done);
+
+  // XC: initialize short arrays.
+  Label XC_template; // Instr template, never exec directly!
+    bind(XC_template);
+    z_xc(0,0,base_pointer_arg,0,base_pointer_arg);
+
+  bind(doXC);
+    add2reg(dst_len, -1);             // Get #bytes-1 for EXECUTE.
+    if (VM_Version::has_ExecuteExtensions()) {
+      z_exrl(dst_len, XC_template);   // Execute XC with var. len.
+    } else {
+      z_larl(tmp_reg, XC_template);
+      z_ex(dst_len,0,Z_R0,tmp_reg);   // Execute XC with var. len.
+    }
+    // z_bru(done);      // fallthru
+
+  bind(done);
+
+  BLOCK_COMMENT("} Clear_Array");
+
+  int block_end = offset();
+  return block_end - block_start;
+}
+
+// Compiler ensures base is doubleword aligned and cnt is count of doublewords.
+// Emitter does not KILL any arguments nor work registers.
+// Emitter generates up to 16 XC instructions, depending on the array length.
+unsigned int MacroAssembler::Clear_Array_Const(long cnt, Register base) {
+  int  block_start    = offset();
+  int  off;
+  int  lineSize_Bytes = AllocatePrefetchStepSize;
+  int  lineSize_DW    = AllocatePrefetchStepSize>>LogBytesPerWord;
+  bool doPrefetch     = VM_Version::has_Prefetch();
+  int  XC_maxlen      = 256;
+  int  numXCInstr     = cnt > 0 ? (cnt*BytesPerWord-1)/XC_maxlen+1 : 0;
+
+  BLOCK_COMMENT("Clear_Array_Const {");
+  assert(cnt*BytesPerWord <= 4096, "ClearArrayConst can handle 4k only");
+
+  // Do less prefetching for very short arrays.
+  if (numXCInstr > 0) {
+    // Prefetch only some cache lines, then begin clearing.
+    if (doPrefetch) {
+      if (cnt*BytesPerWord <= lineSize_Bytes/4) {  // If less than 1/4 of a cache line to clear,
+        z_pfd(0x02, 0, Z_R0, base);                // prefetch just the first cache line.
+      } else {
+        assert(XC_maxlen == lineSize_Bytes, "ClearArrayConst needs 256B cache lines");
+        for (off = 0; (off < AllocatePrefetchLines) && (off <= numXCInstr); off ++) {
+          z_pfd(0x02, off*lineSize_Bytes, Z_R0, base);
+        }
+      }
+    }
+
+    for (off=0; off<(numXCInstr-1); off++) {
+      z_xc(off*XC_maxlen, XC_maxlen-1, base, off*XC_maxlen, base);
+
+      // Prefetch some cache lines in advance.
+      if (doPrefetch && (off <= numXCInstr-AllocatePrefetchLines)) {
+        z_pfd(0x02, (off+AllocatePrefetchLines)*lineSize_Bytes, Z_R0, base);
+      }
+    }
+    if (off*XC_maxlen < cnt*BytesPerWord) {
+      z_xc(off*XC_maxlen, (cnt*BytesPerWord-off*XC_maxlen)-1, base, off*XC_maxlen, base);
+    }
+  }
+  BLOCK_COMMENT("} Clear_Array_Const");
+
+  int block_end = offset();
+  return block_end - block_start;
+}
+
+// Compiler ensures base is doubleword aligned and cnt is #doublewords.
+// Emitter does not KILL cnt and base arguments, since they need to be copied to
+// work registers anyway.
+// Actually, only r0, r1, r4, and r5 (which are work registers) are killed.
+//
+// For very large arrays, exploit MVCLE H/W support.
+// MVCLE instruction automatically exploits H/W-optimized page mover.
+// - Bytes up to next page boundary are cleared with a series of XC to self.
+// - All full pages are cleared with the page mover H/W assist.
+// - Remaining bytes are again cleared by a series of XC to self.
+//
+unsigned int MacroAssembler::Clear_Array_Const_Big(long cnt, Register base_pointer_arg, Register src_addr, Register src_len) {
+  // Src_addr is evenReg.
+  // Src_len is odd_Reg.
+
+  int      block_start = offset();
+  Register dst_len  = Z_R1;      // Holds dst len  for MVCLE.
+  Register dst_addr = Z_R0;      // Holds dst addr for MVCLE.
+
+  BLOCK_COMMENT("Clear_Array_Const_Big {");
+
+  // Get len to clear.
+  load_const_optimized(dst_len, (long)cnt*8L);  // in Bytes = #DW*8
+
+  // Prepare other args to MVCLE.
+  z_lgr(dst_addr, base_pointer_arg);
+  // Indicate unused result.
+  (void) clear_reg(src_len, true, false);  // Src len of MVCLE is zero.
+
+  // Clear.
+  MacroAssembler::move_long_ext(dst_addr, src_addr, 0);
+  BLOCK_COMMENT("} Clear_Array_Const_Big");
+
+  int block_end = offset();
+  return block_end - block_start;
+}
+
+// Allocator.
+unsigned int MacroAssembler::CopyRawMemory_AlignedDisjoint(Register src_reg, Register dst_reg,
+                                                           Register cnt_reg,
+                                                           Register tmp1_reg, Register tmp2_reg) {
+  // Tmp1 is oddReg.
+  // Tmp2 is evenReg.
+
+  int block_start = offset();
+  Label doMVC, doMVCLE, done, MVC_template;
+
+  BLOCK_COMMENT("CopyRawMemory_AlignedDisjoint {");
+
+  // Check for zero len and convert to long.
+  z_ltgfr(cnt_reg, cnt_reg);      // Remember casted value for doSTG case.
+  z_bre(done);                    // Nothing to do if len == 0.
+
+  z_sllg(Z_R1, cnt_reg, 3);       // Dst len in bytes. calc early to have the result ready.
+
+  z_cghi(cnt_reg, 32);            // Check for len <= 256 bytes (<=32 DW).
+  z_brnh(doMVC);                  // If so, use executed MVC to clear.
+
+  bind(doMVCLE);                  // A lot of data (more than 256 bytes).
+  // Prep dest reg pair.
+  z_lgr(Z_R0, dst_reg);           // dst addr
+  // Dst len already in Z_R1.
+  // Prep src reg pair.
+  z_lgr(tmp2_reg, src_reg);       // src addr
+  z_lgr(tmp1_reg, Z_R1);          // Src len same as dst len.
+
+  // Do the copy.
+  move_long_ext(Z_R0, tmp2_reg, 0xb0); // Bypass cache.
+  z_bru(done);                         // All done.
+
+  bind(MVC_template);             // Just some data (not more than 256 bytes).
+  z_mvc(0, 0, dst_reg, 0, src_reg);
+
+  bind(doMVC);
+
+  if (VM_Version::has_ExecuteExtensions()) {
+    add2reg(Z_R1, -1);
+  } else {
+    add2reg(tmp1_reg, -1, Z_R1);
+    z_larl(Z_R1, MVC_template);
+  }
+
+  if (VM_Version::has_Prefetch()) {
+    z_pfd(1,  0,Z_R0,src_reg);
+    z_pfd(2,  0,Z_R0,dst_reg);
+    //    z_pfd(1,256,Z_R0,src_reg);    // Assume very short copy.
+    //    z_pfd(2,256,Z_R0,dst_reg);
+  }
+
+  if (VM_Version::has_ExecuteExtensions()) {
+    z_exrl(Z_R1, MVC_template);
+  } else {
+    z_ex(tmp1_reg, 0, Z_R0, Z_R1);
+  }
+
+  bind(done);
+
+  BLOCK_COMMENT("} CopyRawMemory_AlignedDisjoint");
+
+  int block_end = offset();
+  return block_end - block_start;
+}
+
+//------------------------------------------------------
+//   Special String Intrinsics. Implementation
+//------------------------------------------------------
+
+// Intrinsics for CompactStrings
+
+// Compress char[] to byte[]. odd_reg contains cnt. Kills dst. Early clobber: result
+// The result is the number of characters copied before the first incompatible character was found.
+// If tmp2 is provided and the compression fails, the compression stops exactly at this point and the result is precise.
+//
+// Note: Does not behave exactly like package private StringUTF16 compress java implementation in case of failure:
+// - Different number of characters may have been written to dead array (if tmp2 not provided).
+// - Returns a number <cnt instead of 0. (Result gets compared with cnt.)
+unsigned int MacroAssembler::string_compress(Register result, Register src, Register dst, Register odd_reg,
+                                             Register even_reg, Register tmp, Register tmp2) {
+  int block_start = offset();
+  Label Lloop1, Lloop2, Lslow, Ldone;
+  const Register addr2 = dst, ind1 = result, mask = tmp;
+  const bool precise = (tmp2 != noreg);
+
+  BLOCK_COMMENT("string_compress {");
+
+  z_sll(odd_reg, 1);       // Number of bytes to read. (Must be a positive simm32.)
+  clear_reg(ind1);         // Index to read.
+  z_llilf(mask, 0xFF00FF00);
+  z_ahi(odd_reg, -16);     // Last possible index for fast loop.
+  z_brl(Lslow);
+
+  // ind1: index, even_reg: index increment, odd_reg: index limit
+  z_iihf(mask, 0xFF00FF00);
+  z_lhi(even_reg, 16);
+
+  bind(Lloop1); // 8 Characters per iteration.
+  z_lg(Z_R0, Address(src, ind1));
+  z_lg(Z_R1, Address(src, ind1, 8));
+  if (precise) {
+    if (VM_Version::has_DistinctOpnds()) {
+      z_ogrk(tmp2, Z_R0, Z_R1);
+    } else {
+      z_lgr(tmp2, Z_R0);
+      z_ogr(tmp2, Z_R1);
+    }
+    z_ngr(tmp2, mask);
+    z_brne(Lslow);         // Failed fast case, retry slowly.
+  }
+  z_stcmh(Z_R0, 5, 0, addr2);
+  z_stcm(Z_R0, 5, 2, addr2);
+  if (!precise) { z_ogr(Z_R0, Z_R1); }
+  z_stcmh(Z_R1, 5, 4, addr2);
+  z_stcm(Z_R1, 5, 6, addr2);
+  if (!precise) {
+    z_ngr(Z_R0, mask);
+    z_brne(Ldone);         // Failed (more than needed was written).
+  }
+  z_aghi(addr2, 8);
+  z_brxle(ind1, even_reg, Lloop1);
+
+  bind(Lslow);
+  // Compute index limit and skip if negative.
+  z_ahi(odd_reg, 16-2);    // Last possible index for slow loop.
+  z_lhi(even_reg, 2);
+  z_cr(ind1, odd_reg);
+  z_brh(Ldone);
+
+  bind(Lloop2); // 1 Character per iteration.
+  z_llh(Z_R0, Address(src, ind1));
+  z_tmll(Z_R0, 0xFF00);
+  z_brnaz(Ldone);          // Failed slow case: Return number of written characters.
+  z_stc(Z_R0, Address(addr2));
+  z_aghi(addr2, 1);
+  z_brxle(ind1, even_reg, Lloop2);
+
+  bind(Ldone);             // result = ind1 = 2*cnt
+  z_srl(ind1, 1);
+
+  BLOCK_COMMENT("} string_compress");
+
+  return offset() - block_start;
+}
+
+// Inflate byte[] to char[].
+unsigned int MacroAssembler::string_inflate_trot(Register src, Register dst, Register cnt, Register tmp) {
+  int block_start = offset();
+
+  BLOCK_COMMENT("string_inflate {");
+
+  Register stop_char = Z_R0;
+  Register table     = Z_R1;
+  Register src_addr  = tmp;
+
+  assert_different_registers(Z_R0, Z_R1, tmp, src, dst, cnt);
+  assert(dst->encoding()%2 == 0, "must be even reg");
+  assert(cnt->encoding()%2 == 1, "must be odd reg");
+  assert(cnt->encoding() - dst->encoding() == 1, "must be even/odd pair");
+
+  StubRoutines::zarch::generate_load_trot_table_addr(this, table);  // kills Z_R0 (if ASSERT)
+  clear_reg(stop_char);  // Stop character. Not used here, but initialized to have a defined value.
+  lgr_if_needed(src_addr, src);
+  z_llgfr(cnt, cnt);     // # src characters, must be a positive simm32.
+
+  translate_ot(dst, src_addr, /* mask = */ 0x0001);
+
+  BLOCK_COMMENT("} string_inflate");
+
+  return offset() - block_start;
+}
+
+// Inflate byte[] to char[]. odd_reg contains cnt. Kills src.
+unsigned int MacroAssembler::string_inflate(Register src, Register dst, Register odd_reg,
+                                            Register even_reg, Register tmp) {
+  int block_start = offset();
+
+  BLOCK_COMMENT("string_inflate {");
+
+  Label Lloop1, Lloop2, Lslow, Ldone;
+  const Register addr1 = src, ind2 = tmp;
+
+  z_sll(odd_reg, 1);       // Number of bytes to write. (Must be a positive simm32.)
+  clear_reg(ind2);         // Index to write.
+  z_ahi(odd_reg, -16);     // Last possible index for fast loop.
+  z_brl(Lslow);
+
+  // ind2: index, even_reg: index increment, odd_reg: index limit
+  clear_reg(Z_R0);
+  clear_reg(Z_R1);
+  z_lhi(even_reg, 16);
+
+  bind(Lloop1); // 8 Characters per iteration.
+  z_icmh(Z_R0, 5, 0, addr1);
+  z_icmh(Z_R1, 5, 4, addr1);
+  z_icm(Z_R0, 5, 2, addr1);
+  z_icm(Z_R1, 5, 6, addr1);
+  z_aghi(addr1, 8);
+  z_stg(Z_R0, Address(dst, ind2));
+  z_stg(Z_R1, Address(dst, ind2, 8));
+  z_brxle(ind2, even_reg, Lloop1);
+
+  bind(Lslow);
+  // Compute index limit and skip if negative.
+  z_ahi(odd_reg, 16-2);    // Last possible index for slow loop.
+  z_lhi(even_reg, 2);
+  z_cr(ind2, odd_reg);
+  z_brh(Ldone);
+
+  bind(Lloop2); // 1 Character per iteration.
+  z_llc(Z_R0, Address(addr1));
+  z_sth(Z_R0, Address(dst, ind2));
+  z_aghi(addr1, 1);
+  z_brxle(ind2, even_reg, Lloop2);
+
+  bind(Ldone);
+
+  BLOCK_COMMENT("} string_inflate");
+
+  return offset() - block_start;
+}
+
+// Kills src.
+unsigned int MacroAssembler::has_negatives(Register result, Register src, Register cnt,
+                                           Register odd_reg, Register even_reg, Register tmp) {
+  int block_start = offset();
+  Label Lloop1, Lloop2, Lslow, Lnotfound, Ldone;
+  const Register addr = src, mask = tmp;
+
+  BLOCK_COMMENT("has_negatives {");
+
+  z_llgfr(Z_R1, cnt);      // Number of bytes to read. (Must be a positive simm32.)
+  z_llilf(mask, 0x80808080);
+  z_lhi(result, 1);        // Assume true.
+  // Last possible addr for fast loop.
+  z_lay(odd_reg, -16, Z_R1, src);
+  z_chi(cnt, 16);
+  z_brl(Lslow);
+
+  // ind1: index, even_reg: index increment, odd_reg: index limit
+  z_iihf(mask, 0x80808080);
+  z_lghi(even_reg, 16);
+
+  bind(Lloop1); // 16 bytes per iteration.
+  z_lg(Z_R0, Address(addr));
+  z_lg(Z_R1, Address(addr, 8));
+  z_ogr(Z_R0, Z_R1);
+  z_ngr(Z_R0, mask);
+  z_brne(Ldone);           // If found return 1.
+  z_brxlg(addr, even_reg, Lloop1);
+
+  bind(Lslow);
+  z_aghi(odd_reg, 16-1);   // Last possible addr for slow loop.
+  z_lghi(even_reg, 1);
+  z_cgr(addr, odd_reg);
+  z_brh(Lnotfound);
+
+  bind(Lloop2); // 1 byte per iteration.
+  z_cli(Address(addr), 0x80);
+  z_brnl(Ldone);           // If found return 1.
+  z_brxlg(addr, even_reg, Lloop2);
+
+  bind(Lnotfound);
+  z_lhi(result, 0);
+
+  bind(Ldone);
+
+  BLOCK_COMMENT("} has_negatives");
+
+  return offset() - block_start;
+}
+
+// kill: cnt1, cnt2, odd_reg, even_reg; early clobber: result
+unsigned int MacroAssembler::string_compare(Register str1, Register str2,
+                                            Register cnt1, Register cnt2,
+                                            Register odd_reg, Register even_reg, Register result, int ae) {
+  int block_start = offset();
+
+  assert_different_registers(str1, cnt1, cnt2, odd_reg, even_reg, result);
+  assert_different_registers(str2, cnt1, cnt2, odd_reg, even_reg, result);
+
+  // If strings are equal up to min length, return the length difference.
+  const Register diff = result, // Pre-set result with length difference.
+                 min  = cnt1,   // min number of bytes
+                 tmp  = cnt2;
+
+  // Note: Making use of the fact that compareTo(a, b) == -compareTo(b, a)
+  // we interchange str1 and str2 in the UL case and negate the result.
+  // Like this, str1 is always latin1 encoded, except for the UU case.
+  // In addition, we need 0 (or sign which is 0) extend when using 64 bit register.
+  const bool used_as_LU = (ae == StrIntrinsicNode::LU || ae == StrIntrinsicNode::UL);
+
+  BLOCK_COMMENT("string_compare {");
+
+  if (used_as_LU) {
+    z_srl(cnt2, 1);
+  }
+
+  // See if the lengths are different, and calculate min in cnt1.
+  // Save diff in case we need it for a tie-breaker.
+
+  // diff = cnt1 - cnt2
+  if (VM_Version::has_DistinctOpnds()) {
+    z_srk(diff, cnt1, cnt2);
+  } else {
+    z_lr(diff, cnt1);
+    z_sr(diff, cnt2);
+  }
+  if (str1 != str2) {
+    if (VM_Version::has_LoadStoreConditional()) {
+      z_locr(min, cnt2, Assembler::bcondHigh);
+    } else {
+      Label Lskip;
+      z_brl(Lskip);    // min ok if cnt1 < cnt2
+      z_lr(min, cnt2); // min = cnt2
+      bind(Lskip);
+    }
+  }
+
+  if (ae == StrIntrinsicNode::UU) {
+    z_sra(diff, 1);
+  }
+  if (str1 != str2) {
+    Label Ldone;
+    if (used_as_LU) {
+      // Loop which searches the first difference character by character.
+      Label Lloop;
+      const Register ind1 = Z_R1,
+                     ind2 = min;
+      int stride1 = 1, stride2 = 2; // See comment above.
+
+      // ind1: index, even_reg: index increment, odd_reg: index limit
+      z_llilf(ind1, (unsigned int)(-stride1));
+      z_lhi(even_reg, stride1);
+      add2reg(odd_reg, -stride1, min);
+      clear_reg(ind2); // kills min
+
+      bind(Lloop);
+      z_brxh(ind1, even_reg, Ldone);
+      z_llc(tmp, Address(str1, ind1));
+      z_llh(Z_R0, Address(str2, ind2));
+      z_ahi(ind2, stride2);
+      z_sr(tmp, Z_R0);
+      z_bre(Lloop);
+
+      z_lr(result, tmp);
+
+    } else {
+      // Use clcle in fast loop (only for same encoding).
+      z_lgr(Z_R0, str1);
+      z_lgr(even_reg, str2);
+      z_llgfr(Z_R1, min);
+      z_llgfr(odd_reg, min);
+
+      if (ae == StrIntrinsicNode::LL) {
+        compare_long_ext(Z_R0, even_reg, 0);
+      } else {
+        compare_long_uni(Z_R0, even_reg, 0);
+      }
+      z_bre(Ldone);
+      z_lgr(Z_R1, Z_R0);
+      if (ae == StrIntrinsicNode::LL) {
+        z_llc(Z_R0, Address(even_reg));
+        z_llc(result, Address(Z_R1));
+      } else {
+        z_llh(Z_R0, Address(even_reg));
+        z_llh(result, Address(Z_R1));
+      }
+      z_sr(result, Z_R0);
+    }
+
+    // Otherwise, return the difference between the first mismatched chars.
+    bind(Ldone);
+  }
+
+  if (ae == StrIntrinsicNode::UL) {
+    z_lcr(result, result); // Negate result (see note above).
+  }
+
+  BLOCK_COMMENT("} string_compare");
+
+  return offset() - block_start;
+}
+
+unsigned int MacroAssembler::array_equals(bool is_array_equ, Register ary1, Register ary2, Register limit,
+                                          Register odd_reg, Register even_reg, Register result, bool is_byte) {
+  int block_start = offset();
+
+  BLOCK_COMMENT("array_equals {");
+
+  assert_different_registers(ary1, limit, odd_reg, even_reg);
+  assert_different_registers(ary2, limit, odd_reg, even_reg);
+
+  Label Ldone, Ldone_true, Ldone_false, Lclcle, CLC_template;
+  int base_offset = 0;
+
+  if (ary1 != ary2) {
+    if (is_array_equ) {
+      base_offset = arrayOopDesc::base_offset_in_bytes(is_byte ? T_BYTE : T_CHAR);
+
+      // Return true if the same array.
+      compareU64_and_branch(ary1, ary2, Assembler::bcondEqual, Ldone_true);
+
+      // Return false if one of them is NULL.
+      compareU64_and_branch(ary1, (intptr_t)0, Assembler::bcondEqual, Ldone_false);
+      compareU64_and_branch(ary2, (intptr_t)0, Assembler::bcondEqual, Ldone_false);
+
+      // Load the lengths of arrays.
+      z_llgf(odd_reg, Address(ary1, arrayOopDesc::length_offset_in_bytes()));
+
+      // Return false if the two arrays are not equal length.
+      z_c(odd_reg, Address(ary2, arrayOopDesc::length_offset_in_bytes()));
+      z_brne(Ldone_false);
+
+      // string len in bytes (right operand)
+      if (!is_byte) {
+        z_chi(odd_reg, 128);
+        z_sll(odd_reg, 1); // preserves flags
+        z_brh(Lclcle);
+      } else {
+        compareU32_and_branch(odd_reg, (intptr_t)256, Assembler::bcondHigh, Lclcle);
+      }
+    } else {
+      z_llgfr(odd_reg, limit); // Need to zero-extend prior to using the value.
+      compareU32_and_branch(limit, (intptr_t)256, Assembler::bcondHigh, Lclcle);
+    }
+
+
+    // Use clc instruction for up to 256 bytes.
+    {
+      Register str1_reg = ary1,
+          str2_reg = ary2;
+      if (is_array_equ) {
+        str1_reg = Z_R1;
+        str2_reg = even_reg;
+        add2reg(str1_reg, base_offset, ary1); // string addr (left operand)
+        add2reg(str2_reg, base_offset, ary2); // string addr (right operand)
+      }
+      z_ahi(odd_reg, -1); // Clc uses decremented limit. Also compare result to 0.
+      z_brl(Ldone_true);
+      // Note: We could jump to the template if equal.
+
+      assert(VM_Version::has_ExecuteExtensions(), "unsupported hardware");
+      z_exrl(odd_reg, CLC_template);
+      z_bre(Ldone_true);
+      // fall through
+
+      bind(Ldone_false);
+      clear_reg(result);
+      z_bru(Ldone);
+
+      bind(CLC_template);
+      z_clc(0, 0, str1_reg, 0, str2_reg);
+    }
+
+    // Use clcle instruction.
+    {
+      bind(Lclcle);
+      add2reg(even_reg, base_offset, ary2); // string addr (right operand)
+      add2reg(Z_R0, base_offset, ary1);     // string addr (left operand)
+
+      z_lgr(Z_R1, odd_reg); // string len in bytes (left operand)
+      if (is_byte) {
+        compare_long_ext(Z_R0, even_reg, 0);
+      } else {
+        compare_long_uni(Z_R0, even_reg, 0);
+      }
+      z_lghi(result, 0); // Preserve flags.
+      z_brne(Ldone);
+    }
+  }
+  // fall through
+
+  bind(Ldone_true);
+  z_lghi(result, 1); // All characters are equal.
+  bind(Ldone);
+
+  BLOCK_COMMENT("} array_equals");
+
+  return offset() - block_start;
+}
+
+// kill: haycnt, needlecnt, odd_reg, even_reg; early clobber: result
+unsigned int MacroAssembler::string_indexof(Register result, Register haystack, Register haycnt,
+                                            Register needle, Register needlecnt, int needlecntval,
+                                            Register odd_reg, Register even_reg, int ae) {
+  int block_start = offset();
+
+  // Ensure 0<needlecnt<=haycnt in ideal graph as prerequisite!
+  assert(ae != StrIntrinsicNode::LU, "Invalid encoding");
+  const int h_csize = (ae == StrIntrinsicNode::LL) ? 1 : 2;
+  const int n_csize = (ae == StrIntrinsicNode::UU) ? 2 : 1;
+  Label L_needle1, L_Found, L_NotFound;
+
+  BLOCK_COMMENT("string_indexof {");
+
+  if (needle == haystack) {
+    z_lhi(result, 0);
+  } else {
+
+  // Load first character of needle (R0 used by search_string instructions).
+  if (n_csize == 2) { z_llgh(Z_R0, Address(needle)); } else { z_llgc(Z_R0, Address(needle)); }
+
+  // Compute last haystack addr to use if no match gets found.
+  if (needlecnt != noreg) { // variable needlecnt
+    z_ahi(needlecnt, -1); // Remaining characters after first one.
+    z_sr(haycnt, needlecnt); // Compute index succeeding last element to compare.
+    if (n_csize == 2) { z_sll(needlecnt, 1); } // In bytes.
+  } else { // constant needlecnt
+    assert((needlecntval & 0x7fff) == needlecntval, "must be positive simm16 immediate");
+    // Compute index succeeding last element to compare.
+    if (needlecntval != 1) { z_ahi(haycnt, 1 - needlecntval); }
+  }
+
+  z_llgfr(haycnt, haycnt); // Clear high half.
+  z_lgr(result, haystack); // Final result will be computed from needle start pointer.
+  if (h_csize == 2) { z_sll(haycnt, 1); } // Scale to number of bytes.
+  z_agr(haycnt, haystack); // Point to address succeeding last element (haystack+scale*(haycnt-needlecnt+1)).
+
+  if (h_csize != n_csize) {
+    assert(ae == StrIntrinsicNode::UL, "Invalid encoding");
+
+    if (needlecnt != noreg || needlecntval != 1) {
+      if (needlecnt != noreg) {
+        compare32_and_branch(needlecnt, (intptr_t)0, Assembler::bcondEqual, L_needle1);
+      }
+
+      // Main Loop: UL version (now we have at least 2 characters).
+      Label L_OuterLoop, L_InnerLoop, L_Skip;
+      bind(L_OuterLoop); // Search for 1st 2 characters.
+      z_lgr(Z_R1, haycnt);
+      MacroAssembler::search_string_uni(Z_R1, result);
+      z_brc(Assembler::bcondNotFound, L_NotFound);
+      z_lgr(result, Z_R1);
+
+      z_lghi(Z_R1, n_csize);
+      z_lghi(even_reg, h_csize);
+      bind(L_InnerLoop);
+      z_llgc(odd_reg, Address(needle, Z_R1));
+      z_ch(odd_reg, Address(result, even_reg));
+      z_brne(L_Skip);
+      if (needlecnt != noreg) { z_cr(Z_R1, needlecnt); } else { z_chi(Z_R1, needlecntval - 1); }
+      z_brnl(L_Found);
+      z_aghi(Z_R1, n_csize);
+      z_aghi(even_reg, h_csize);
+      z_bru(L_InnerLoop);
+
+      bind(L_Skip);
+      z_aghi(result, h_csize); // This is the new address we want to use for comparing.
+      z_bru(L_OuterLoop);
+    }
+
+  } else {
+    const intptr_t needle_bytes = (n_csize == 2) ? ((needlecntval - 1) << 1) : (needlecntval - 1);
+    Label L_clcle;
+
+    if (needlecnt != noreg || (needlecntval != 1 && needle_bytes <= 256)) {
+      if (needlecnt != noreg) {
+        compare32_and_branch(needlecnt, 256, Assembler::bcondHigh, L_clcle);
+        z_ahi(needlecnt, -1); // remaining bytes -1 (for CLC)
+        z_brl(L_needle1);
+      }
+
+      // Main Loop: clc version (now we have at least 2 characters).
+      Label L_OuterLoop, CLC_template;
+      bind(L_OuterLoop); // Search for 1st 2 characters.
+      z_lgr(Z_R1, haycnt);
+      if (h_csize == 1) {
+        MacroAssembler::search_string(Z_R1, result);
+      } else {
+        MacroAssembler::search_string_uni(Z_R1, result);
+      }
+      z_brc(Assembler::bcondNotFound, L_NotFound);
+      z_lgr(result, Z_R1);
+
+      if (needlecnt != noreg) {
+        assert(VM_Version::has_ExecuteExtensions(), "unsupported hardware");
+        z_exrl(needlecnt, CLC_template);
+      } else {
+        z_clc(h_csize, needle_bytes -1, Z_R1, n_csize, needle);
+      }
+      z_bre(L_Found);
+      z_aghi(result, h_csize); // This is the new address we want to use for comparing.
+      z_bru(L_OuterLoop);
+
+      if (needlecnt != noreg) {
+        bind(CLC_template);
+        z_clc(h_csize, 0, Z_R1, n_csize, needle);
+      }
+    }
+
+    if (needlecnt != noreg || needle_bytes > 256) {
+      bind(L_clcle);
+
+      // Main Loop: clcle version (now we have at least 256 bytes).
+      Label L_OuterLoop, CLC_template;
+      bind(L_OuterLoop); // Search for 1st 2 characters.
+      z_lgr(Z_R1, haycnt);
+      if (h_csize == 1) {
+        MacroAssembler::search_string(Z_R1, result);
+      } else {
+        MacroAssembler::search_string_uni(Z_R1, result);
+      }
+      z_brc(Assembler::bcondNotFound, L_NotFound);
+
+      add2reg(Z_R0, n_csize, needle);
+      add2reg(even_reg, h_csize, Z_R1);
+      z_lgr(result, Z_R1);
+      if (needlecnt != noreg) {
+        z_llgfr(Z_R1, needlecnt); // needle len in bytes (left operand)
+        z_llgfr(odd_reg, needlecnt);
+      } else {
+        load_const_optimized(Z_R1, needle_bytes);
+        if (Immediate::is_simm16(needle_bytes)) { z_lghi(odd_reg, needle_bytes); } else { z_lgr(odd_reg, Z_R1); }
+      }
+      if (h_csize == 1) {
+        compare_long_ext(Z_R0, even_reg, 0);
+      } else {
+        compare_long_uni(Z_R0, even_reg, 0);
+      }
+      z_bre(L_Found);
+
+      if (n_csize == 2) { z_llgh(Z_R0, Address(needle)); } else { z_llgc(Z_R0, Address(needle)); } // Reload.
+      z_aghi(result, h_csize); // This is the new address we want to use for comparing.
+      z_bru(L_OuterLoop);
+    }
+  }
+
+  if (needlecnt != noreg || needlecntval == 1) {
+    bind(L_needle1);
+
+    // Single needle character version.
+    if (h_csize == 1) {
+      MacroAssembler::search_string(haycnt, result);
+    } else {
+      MacroAssembler::search_string_uni(haycnt, result);
+    }
+    z_lgr(result, haycnt);
+    z_brc(Assembler::bcondFound, L_Found);
+  }
+
+  bind(L_NotFound);
+  add2reg(result, -1, haystack); // Return -1.
+
+  bind(L_Found); // Return index (or -1 in fallthrough case).
+  z_sgr(result, haystack);
+  if (h_csize == 2) { z_srag(result, result, exact_log2(sizeof(jchar))); }
+  }
+  BLOCK_COMMENT("} string_indexof");
+
+  return offset() - block_start;
+}
+
+// early clobber: result
+unsigned int MacroAssembler::string_indexof_char(Register result, Register haystack, Register haycnt,
+                                                 Register needle, jchar needleChar, Register odd_reg, Register even_reg, bool is_byte) {
+  int block_start = offset();
+
+  BLOCK_COMMENT("string_indexof_char {");
+
+  if (needle == haystack) {
+    z_lhi(result, 0);
+  } else {
+
+  Label Ldone;
+
+  z_llgfr(odd_reg, haycnt);  // Preset loop ctr/searchrange end.
+  if (needle == noreg) {
+    load_const_optimized(Z_R0, (unsigned long)needleChar);
+  } else {
+    if (is_byte) {
+      z_llgcr(Z_R0, needle); // First (and only) needle char.
+    } else {
+      z_llghr(Z_R0, needle); // First (and only) needle char.
+    }
+  }
+
+  if (!is_byte) {
+    z_agr(odd_reg, odd_reg); // Calc #bytes to be processed with SRSTU.
+  }
+
+  z_lgr(even_reg, haystack); // haystack addr
+  z_agr(odd_reg, haystack);  // First char after range end.
+  z_lghi(result, -1);
+
+  if (is_byte) {
+    MacroAssembler::search_string(odd_reg, even_reg);
+  } else {
+    MacroAssembler::search_string_uni(odd_reg, even_reg);
+  }
+  z_brc(Assembler::bcondNotFound, Ldone);
+  if (is_byte) {
+    if (VM_Version::has_DistinctOpnds()) {
+      z_sgrk(result, odd_reg, haystack);
+    } else {
+      z_sgr(odd_reg, haystack);
+      z_lgr(result, odd_reg);
+    }
+  } else {
+    z_slgr(odd_reg, haystack);
+    z_srlg(result, odd_reg, exact_log2(sizeof(jchar)));
+  }
+
+  bind(Ldone);
+  }
+  BLOCK_COMMENT("} string_indexof_char");
+
+  return offset() - block_start;
+}
+
+
+//-------------------------------------------------
+//   Constants (scalar and oop) in constant pool
+//-------------------------------------------------
+
+// Add a non-relocated constant to the CP.
+int MacroAssembler::store_const_in_toc(AddressLiteral& val) {
+  long    value  = val.value();
+  address tocPos = long_constant(value);
+
+  if (tocPos != NULL) {
+    int tocOffset = (int)(tocPos - code()->consts()->start());
+    return tocOffset;
+  }
+  // Address_constant returned NULL, so no constant entry has been created.
+  // In that case, we return a "fatal" offset, just in case that subsequently
+  // generated access code is executed.
+  return -1;
+}
+
+// Returns the TOC offset where the address is stored.
+// Add a relocated constant to the CP.
+int MacroAssembler::store_oop_in_toc(AddressLiteral& oop) {
+  // Use RelocationHolder::none for the constant pool entry.
+  // Otherwise we will end up with a failing NativeCall::verify(x),
+  // where x is the address of the constant pool entry.
+  address tocPos = address_constant((address)oop.value(), RelocationHolder::none);
+
+  if (tocPos != NULL) {
+    int              tocOffset = (int)(tocPos - code()->consts()->start());
+    RelocationHolder rsp = oop.rspec();
+    Relocation      *rel = rsp.reloc();
+
+    // Store toc_offset in relocation, used by call_far_patchable.
+    if ((relocInfo::relocType)rel->type() == relocInfo::runtime_call_w_cp_type) {
+      ((runtime_call_w_cp_Relocation *)(rel))->set_constant_pool_offset(tocOffset);
+    }
+    // Relocate at the load's pc.
+    relocate(rsp);
+
+    return tocOffset;
+  }
+  // Address_constant returned NULL, so no constant entry has been created
+  // in that case, we return a "fatal" offset, just in case that subsequently
+  // generated access code is executed.
+  return -1;
+}
+
+bool MacroAssembler::load_const_from_toc(Register dst, AddressLiteral& a, Register Rtoc) {
+  int     tocOffset = store_const_in_toc(a);
+  if (tocOffset == -1) return false;
+  address tocPos    = tocOffset + code()->consts()->start();
+  assert((address)code()->consts()->start() != NULL, "Please add CP address");
+
+  load_long_pcrelative(dst, tocPos);
+  return true;
+}
+
+bool MacroAssembler::load_oop_from_toc(Register dst, AddressLiteral& a, Register Rtoc) {
+  int     tocOffset = store_oop_in_toc(a);
+  if (tocOffset == -1) return false;
+  address tocPos    = tocOffset + code()->consts()->start();
+  assert((address)code()->consts()->start() != NULL, "Please add CP address");
+
+  load_addr_pcrelative(dst, tocPos);
+  return true;
+}
+
+// If the instruction sequence at the given pc is a load_const_from_toc
+// sequence, return the value currently stored at the referenced position
+// in the TOC.
+intptr_t MacroAssembler::get_const_from_toc(address pc) {
+
+  assert(is_load_const_from_toc(pc), "must be load_const_from_pool");
+
+  long    offset  = get_load_const_from_toc_offset(pc);
+  address dataLoc = NULL;
+  if (is_load_const_from_toc_pcrelative(pc)) {
+    dataLoc = pc + offset;
+  } else {
+    CodeBlob* cb = CodeCache::find_blob_unsafe(pc);   // Else we get assertion if nmethod is zombie.
+    assert(cb && cb->is_nmethod(), "sanity");
+    nmethod* nm = (nmethod*)cb;
+    dataLoc = nm->ctable_begin() + offset;
+  }
+  return *(intptr_t *)dataLoc;
+}
+
+// If the instruction sequence at the given pc is a load_const_from_toc
+// sequence, copy the passed-in new_data value into the referenced
+// position in the TOC.
+void MacroAssembler::set_const_in_toc(address pc, unsigned long new_data, CodeBlob *cb) {
+  assert(is_load_const_from_toc(pc), "must be load_const_from_pool");
+
+  long    offset = MacroAssembler::get_load_const_from_toc_offset(pc);
+  address dataLoc = NULL;
+  if (is_load_const_from_toc_pcrelative(pc)) {
+    dataLoc = pc+offset;
+  } else {
+    nmethod* nm = CodeCache::find_nmethod(pc);
+    assert((cb == NULL) || (nm == (nmethod*)cb), "instruction address should be in CodeBlob");
+    dataLoc = nm->ctable_begin() + offset;
+  }
+  if (*(unsigned long *)dataLoc != new_data) { // Prevent cache invalidation: update only if necessary.
+    *(unsigned long *)dataLoc = new_data;
+  }
+}
+
+// Dynamic TOC. Getter must only be called if "a" is a load_const_from_toc
+// site. Verify by calling is_load_const_from_toc() before!!
+// Offset is +/- 2**32 -> use long.
+long MacroAssembler::get_load_const_from_toc_offset(address a) {
+  assert(is_load_const_from_toc_pcrelative(a), "expected pc relative load");
+  //  expected code sequence:
+  //    z_lgrl(t, simm32);    len = 6
+  unsigned long inst;
+  unsigned int  len = get_instruction(a, &inst);
+  return get_pcrel_offset(inst);
+}
+
+//**********************************************************************************
+//  inspection of generated instruction sequences for a particular pattern
+//**********************************************************************************
+
+bool MacroAssembler::is_load_const_from_toc_pcrelative(address a) {
+#ifdef ASSERT
+  unsigned long inst;
+  unsigned int  len = get_instruction(a+2, &inst);
+  if ((len == 6) && is_load_pcrelative_long(a) && is_call_pcrelative_long(inst)) {
+    const int range = 128;
+    Assembler::dump_code_range(tty, a, range, "instr(a) == z_lgrl && instr(a+2) == z_brasl");
+    VM_Version::z_SIGSEGV();
+  }
+#endif
+  // expected code sequence:
+  //   z_lgrl(t, relAddr32);    len = 6
+  //TODO: verify accessed data is in CP, if possible.
+  return is_load_pcrelative_long(a);  // TODO: might be too general. Currently, only lgrl is used.
+}
+
+bool MacroAssembler::is_load_const_from_toc_call(address a) {
+  return is_load_const_from_toc(a) && is_call_byregister(a + load_const_from_toc_size());
+}
+
+bool MacroAssembler::is_load_const_call(address a) {
+  return is_load_const(a) && is_call_byregister(a + load_const_size());
+}
+
+//-------------------------------------------------
+//   Emitters for some really CICS instructions
+//-------------------------------------------------
+
+void MacroAssembler::move_long_ext(Register dst, Register src, unsigned int pad) {
+  assert(dst->encoding()%2==0, "must be an even/odd register pair");
+  assert(src->encoding()%2==0, "must be an even/odd register pair");
+  assert(pad<256, "must be a padding BYTE");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_mvcle(dst, src, pad);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::compare_long_ext(Register left, Register right, unsigned int pad) {
+  assert(left->encoding() % 2 == 0, "must be an even/odd register pair");
+  assert(right->encoding() % 2 == 0, "must be an even/odd register pair");
+  assert(pad<256, "must be a padding BYTE");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_clcle(left, right, pad, Z_R0);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::compare_long_uni(Register left, Register right, unsigned int pad) {
+  assert(left->encoding() % 2 == 0, "must be an even/odd register pair");
+  assert(right->encoding() % 2 == 0, "must be an even/odd register pair");
+  assert(pad<=0xfff, "must be a padding HALFWORD");
+  assert(VM_Version::has_ETF2(), "instruction must be available");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_clclu(left, right, pad, Z_R0);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::search_string(Register end, Register start) {
+  assert(end->encoding() != 0, "end address must not be in R0");
+  assert(start->encoding() != 0, "start address must not be in R0");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_srst(end, start);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::search_string_uni(Register end, Register start) {
+  assert(end->encoding() != 0, "end address must not be in R0");
+  assert(start->encoding() != 0, "start address must not be in R0");
+  assert(VM_Version::has_ETF3(), "instruction must be available");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_srstu(end, start);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::kmac(Register srcBuff) {
+  assert(srcBuff->encoding()     != 0, "src buffer address can't be in Z_R0");
+  assert(srcBuff->encoding() % 2 == 0, "src buffer/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_kmac(Z_R0, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::kimd(Register srcBuff) {
+  assert(srcBuff->encoding()     != 0, "src buffer address can't be in Z_R0");
+  assert(srcBuff->encoding() % 2 == 0, "src buffer/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_kimd(Z_R0, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::klmd(Register srcBuff) {
+  assert(srcBuff->encoding()     != 0, "src buffer address can't be in Z_R0");
+  assert(srcBuff->encoding() % 2 == 0, "src buffer/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_klmd(Z_R0, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::km(Register dstBuff, Register srcBuff) {
+  // DstBuff and srcBuff are allowed to be the same register (encryption in-place).
+  // DstBuff and srcBuff storage must not overlap destructively, and neither must overlap the parameter block.
+  assert(srcBuff->encoding()     != 0, "src buffer address can't be in Z_R0");
+  assert(dstBuff->encoding() % 2 == 0, "dst buffer addr must be an even register");
+  assert(srcBuff->encoding() % 2 == 0, "src buffer addr/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_km(dstBuff, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::kmc(Register dstBuff, Register srcBuff) {
+  // DstBuff and srcBuff are allowed to be the same register (encryption in-place).
+  // DstBuff and srcBuff storage must not overlap destructively, and neither must overlap the parameter block.
+  assert(srcBuff->encoding()     != 0, "src buffer address can't be in Z_R0");
+  assert(dstBuff->encoding() % 2 == 0, "dst buffer addr must be an even register");
+  assert(srcBuff->encoding() % 2 == 0, "src buffer addr/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_kmc(dstBuff, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::cksm(Register crcBuff, Register srcBuff) {
+  assert(srcBuff->encoding() % 2 == 0, "src buffer addr/len must be an even/odd register pair");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_cksm(crcBuff, srcBuff);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::translate_oo(Register r1, Register r2, uint m3) {
+  assert(r1->encoding() % 2 == 0, "dst addr/src len must be an even/odd register pair");
+  assert((m3 & 0b1110) == 0, "Unused mask bits must be zero");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_troo(r1, r2, m3);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::translate_ot(Register r1, Register r2, uint m3) {
+  assert(r1->encoding() % 2 == 0, "dst addr/src len must be an even/odd register pair");
+  assert((m3 & 0b1110) == 0, "Unused mask bits must be zero");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_trot(r1, r2, m3);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::translate_to(Register r1, Register r2, uint m3) {
+  assert(r1->encoding() % 2 == 0, "dst addr/src len must be an even/odd register pair");
+  assert((m3 & 0b1110) == 0, "Unused mask bits must be zero");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_trto(r1, r2, m3);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::translate_tt(Register r1, Register r2, uint m3) {
+  assert(r1->encoding() % 2 == 0, "dst addr/src len must be an even/odd register pair");
+  assert((m3 & 0b1110) == 0, "Unused mask bits must be zero");
+
+  Label retry;
+  bind(retry);
+  Assembler::z_trtt(r1, r2, m3);
+  Assembler::z_brc(Assembler::bcondOverflow /* CC==3 (iterate) */, retry);
+}
+
+void MacroAssembler::generate_safepoint_check(Label& slow_path, Register scratch, bool may_relocate) {
+  if (scratch == noreg) scratch = Z_R1;
+  address Astate = SafepointSynchronize::address_of_state();
+  BLOCK_COMMENT("safepoint check:");
+
+  if (may_relocate) {
+    ptrdiff_t total_distance = Astate - this->pc();
+    if (RelAddr::is_in_range_of_RelAddr32(total_distance)) {
+      RelocationHolder rspec = external_word_Relocation::spec(Astate);
+      (this)->relocate(rspec, relocInfo::pcrel_addr_format);
+      load_absolute_address(scratch, Astate);
+    } else {
+      load_const_optimized(scratch, Astate);
+    }
+  } else {
+    load_absolute_address(scratch, Astate);
+  }
+  z_cli(/*SafepointSynchronize::sz_state()*/4-1, scratch, SafepointSynchronize::_not_synchronized);
+  z_brne(slow_path);
+}
+
+
+void MacroAssembler::generate_type_profiling(const Register Rdata,
+                                             const Register Rreceiver_klass,
+                                             const Register Rwanted_receiver_klass,
+                                             const Register Rmatching_row,
+                                             bool is_virtual_call) {
+  const int row_size = in_bytes(ReceiverTypeData::receiver_offset(1)) -
+                       in_bytes(ReceiverTypeData::receiver_offset(0));
+  const int num_rows = ReceiverTypeData::row_limit();
+  NearLabel found_free_row;
+  NearLabel do_increment;
+  NearLabel found_no_slot;
+
+  BLOCK_COMMENT("type profiling {");
+
+  // search for:
+  //    a) The type given in Rwanted_receiver_klass.
+  //    b) The *first* empty row.
+
+  // First search for a) only, just running over b) with no regard.
+  // This is possible because
+  //    wanted_receiver_class == receiver_class  &&  wanted_receiver_class == 0
+  // is never true (receiver_class can't be zero).
+  for (int row_num = 0; row_num < num_rows; row_num++) {
+    // Row_offset should be a well-behaved positive number. The generated code relies
+    // on that wrt constant code size. Add2reg can handle all row_offset values, but
+    // will have to vary generated code size.
+    int row_offset = in_bytes(ReceiverTypeData::receiver_offset(row_num));
+    assert(Displacement::is_shortDisp(row_offset), "Limitation of generated code");
+
+    // Is Rwanted_receiver_klass in this row?
+    if (VM_Version::has_CompareBranch()) {
+      z_lg(Rwanted_receiver_klass, row_offset, Z_R0, Rdata);
+      // Rmatching_row = Rdata + row_offset;
+      add2reg(Rmatching_row, row_offset, Rdata);
+      // if (*row_recv == (intptr_t) receiver_klass) goto fill_existing_slot;
+      compare64_and_branch(Rwanted_receiver_klass, Rreceiver_klass, Assembler::bcondEqual, do_increment);
+    } else {
+      add2reg(Rmatching_row, row_offset, Rdata);
+      z_cg(Rreceiver_klass, row_offset, Z_R0, Rdata);
+      z_bre(do_increment);
+    }
+  }
+
+  // Now that we did not find a match, let's search for b).
+
+  // We could save the first calculation of Rmatching_row if we woud search for a) in reverse order.
+  // We would then end up here with Rmatching_row containing the value for row_num == 0.
+  // We would not see much benefit, if any at all, because the CPU can schedule
+  // two instructions together with a branch anyway.
+  for (int row_num = 0; row_num < num_rows; row_num++) {
+    int row_offset = in_bytes(ReceiverTypeData::receiver_offset(row_num));
+
+    // Has this row a zero receiver_klass, i.e. is it empty?
+    if (VM_Version::has_CompareBranch()) {
+      z_lg(Rwanted_receiver_klass, row_offset, Z_R0, Rdata);
+      // Rmatching_row = Rdata + row_offset
+      add2reg(Rmatching_row, row_offset, Rdata);
+      // if (*row_recv == (intptr_t) 0) goto found_free_row
+      compare64_and_branch(Rwanted_receiver_klass, (intptr_t)0, Assembler::bcondEqual, found_free_row);
+    } else {
+      add2reg(Rmatching_row, row_offset, Rdata);
+      load_and_test_long(Rwanted_receiver_klass, Address(Rdata, row_offset));
+      z_bre(found_free_row);  // zero -> Found a free row.
+    }
+  }
+
+  // No match, no empty row found.
+  // Increment total counter to indicate polymorphic case.
+  if (is_virtual_call) {
+    add2mem_64(Address(Rdata, CounterData::count_offset()), 1, Rmatching_row);
+  }
+  z_bru(found_no_slot);
+
+  // Here we found an empty row, but we have not found Rwanted_receiver_klass.
+  // Rmatching_row holds the address to the first empty row.
+  bind(found_free_row);
+  // Store receiver_klass into empty slot.
+  z_stg(Rreceiver_klass, 0, Z_R0, Rmatching_row);
+
+  // Increment the counter of Rmatching_row.
+  bind(do_increment);
+  ByteSize counter_offset = ReceiverTypeData::receiver_count_offset(0) - ReceiverTypeData::receiver_offset(0);
+  add2mem_64(Address(Rmatching_row, counter_offset), 1, Rdata);
+
+  bind(found_no_slot);
+
+  BLOCK_COMMENT("} type profiling");
+}
+
+//---------------------------------------
+// Helpers for Intrinsic Emitters
+//---------------------------------------
+
+/**
+ * uint32_t crc;
+ * timesXtoThe32[crc & 0xFF] ^ (crc >> 8);
+ */
+void MacroAssembler::fold_byte_crc32(Register crc, Register val, Register table, Register tmp) {
+  assert_different_registers(crc, table, tmp);
+  assert_different_registers(val, table);
+  if (crc == val) {      // Must rotate first to use the unmodified value.
+    rotate_then_insert(tmp, val, 56-2, 63-2, 2, true);  // Insert byte 7 of val, shifted left by 2, into byte 6..7 of tmp, clear the rest.
+    z_srl(crc, 8);       // Unsigned shift, clear leftmost 8 bits.
+  } else {
+    z_srl(crc, 8);       // Unsigned shift, clear leftmost 8 bits.
+    rotate_then_insert(tmp, val, 56-2, 63-2, 2, true);  // Insert byte 7 of val, shifted left by 2, into byte 6..7 of tmp, clear the rest.
+  }
+  z_x(crc, Address(table, tmp, 0));
+}
+
+/**
+ * uint32_t crc;
+ * timesXtoThe32[crc & 0xFF] ^ (crc >> 8);
+ */
+void MacroAssembler::fold_8bit_crc32(Register crc, Register table, Register tmp) {
+  fold_byte_crc32(crc, crc, table, tmp);
+}
+
+/**
+ * Emits code to update CRC-32 with a byte value according to constants in table.
+ *
+ * @param [in,out]crc Register containing the crc.
+ * @param [in]val     Register containing the byte to fold into the CRC.
+ * @param [in]table   Register containing the table of crc constants.
+ *
+ * uint32_t crc;
+ * val = crc_table[(val ^ crc) & 0xFF];
+ * crc = val ^ (crc >> 8);
+ */
+void MacroAssembler::update_byte_crc32(Register crc, Register val, Register table) {
+  z_xr(val, crc);
+  fold_byte_crc32(crc, val, table, val);
+}
+
+
+/**
+ * @param crc   register containing existing CRC (32-bit)
+ * @param buf   register pointing to input byte buffer (byte*)
+ * @param len   register containing number of bytes
+ * @param table register pointing to CRC table
+ */
+void MacroAssembler::update_byteLoop_crc32(Register crc, Register buf, Register len, Register table,
+                                           Register data, bool invertCRC) {
+  assert_different_registers(crc, buf, len, table, data);
+
+  Label L_mainLoop, L_done;
+  const int mainLoop_stepping = 1;
+
+  // Process all bytes in a single-byte loop.
+  z_ltr(len, len);
+  z_brnh(L_done);
+
+  if (invertCRC) {
+    not_(crc, noreg, false); // ~c
+  }
+
+  bind(L_mainLoop);
+    z_llgc(data, Address(buf, (intptr_t)0));// Current byte of input buffer (zero extended). Avoids garbage in upper half of register.
+    add2reg(buf, mainLoop_stepping);        // Advance buffer position.
+    update_byte_crc32(crc, data, table);
+    z_brct(len, L_mainLoop);                // Iterate.
+
+  if (invertCRC) {
+    not_(crc, noreg, false); // ~c
+  }
+
+  bind(L_done);
+}
+
+/**
+ * Emits code to update CRC-32 with a 4-byte value according to constants in table.
+ * Implementation according to jdk/src/share/native/java/util/zip/zlib-1.2.8/crc32.c.
+ *
+ */
+void MacroAssembler::update_1word_crc32(Register crc, Register buf, Register table, int bufDisp, int bufInc,
+                                        Register t0,  Register t1,  Register t2,    Register t3) {
+  // This is what we implement (the DOBIG4 part):
+  //
+  // #define DOBIG4 c ^= *++buf4; \
+  //         c = crc_table[4][c & 0xff] ^ crc_table[5][(c >> 8) & 0xff] ^ \
+  //             crc_table[6][(c >> 16) & 0xff] ^ crc_table[7][c >> 24]
+  // #define DOBIG32 DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4
+  const int ix0 = 4*(4*CRC32_COLUMN_SIZE);
+  const int ix1 = 5*(4*CRC32_COLUMN_SIZE);
+  const int ix2 = 6*(4*CRC32_COLUMN_SIZE);
+  const int ix3 = 7*(4*CRC32_COLUMN_SIZE);
+
+  // XOR crc with next four bytes of buffer.
+  lgr_if_needed(t0, crc);
+  z_x(t0, Address(buf, bufDisp));
+  if (bufInc != 0) {
+    add2reg(buf, bufInc);
+  }
+
+  // Chop crc into 4 single-byte pieces, shifted left 2 bits, to form the table indices.
+  rotate_then_insert(t3, t0, 56-2, 63-2, 2,    true);  // ((c >>  0) & 0xff) << 2
+  rotate_then_insert(t2, t0, 56-2, 63-2, 2-8,  true);  // ((c >>  8) & 0xff) << 2
+  rotate_then_insert(t1, t0, 56-2, 63-2, 2-16, true);  // ((c >> 16) & 0xff) << 2
+  rotate_then_insert(t0, t0, 56-2, 63-2, 2-24, true);  // ((c >> 24) & 0xff) << 2
+
+  // Load pre-calculated table values.
+  // Use columns 4..7 for big-endian.
+  z_ly(t3, Address(table, t3, (intptr_t)ix0));
+  z_ly(t2, Address(table, t2, (intptr_t)ix1));
+  z_ly(t1, Address(table, t1, (intptr_t)ix2));
+  z_ly(t0, Address(table, t0, (intptr_t)ix3));
+
+  // Calculate new crc from table values.
+  z_xr(t2, t3);
+  z_xr(t0, t1);
+  z_xr(t0, t2);  // Now crc contains the final checksum value.
+  lgr_if_needed(crc, t0);
+}
+
+/**
+ * @param crc   register containing existing CRC (32-bit)
+ * @param buf   register pointing to input byte buffer (byte*)
+ * @param len   register containing number of bytes
+ * @param table register pointing to CRC table
+ *
+ * uses Z_R10..Z_R13 as work register. Must be saved/restored by caller!
+ */
+void MacroAssembler::kernel_crc32_2word(Register crc, Register buf, Register len, Register table,
+                                        Register t0,  Register t1,  Register t2,  Register t3) {
+  assert_different_registers(crc, buf, len, table);
+
+  Label L_mainLoop, L_tail;
+  Register  data = t0;
+  Register  ctr  = Z_R0;
+  const int mainLoop_stepping = 8;
+  const int tailLoop_stepping = 1;
+  const int log_stepping      = exact_log2(mainLoop_stepping);
+
+  // Don't test for len <= 0 here. This pathological case should not occur anyway.
+  // Optimizing for it by adding a test and a branch seems to be a waste of CPU cycles.
+  // The situation itself is detected and handled correctly by the conditional branches
+  // following aghi(len, -stepping) and aghi(len, +stepping).
+
+  not_(crc, noreg, false);             // 1s complement of crc
+
+#if 0
+  {
+    // Pre-mainLoop alignment did not show any positive effect on performance.
+    // We leave the code in for reference. Maybe the vector instructions in z13 depend on alignment.
+
+    z_cghi(len, mainLoop_stepping);    // Alignment is useless for short data streams.
+    z_brnh(L_tail);
+
+    // Align buf to word (4-byte) boundary.
+    z_lcr(ctr, buf);
+    rotate_then_insert(ctr, ctr, 62, 63, 0, true); // TODO: should set cc
+    z_sgfr(len, ctr);                  // Remaining len after alignment.
+
+    update_byteLoop_crc32(crc, buf, ctr, table, data, false);
+  }
+#endif
+
+  // Check for short (<mainLoop_stepping bytes) buffer.
+  z_srag(ctr, len, log_stepping);
+  z_brnh(L_tail);
+
+  z_lrvr(crc, crc);             // Revert byte order because we are dealing with big-endian data.
+  rotate_then_insert(len, len, 64-log_stepping, 63, 0, true); // #bytes for tailLoop
+
+  BIND(L_mainLoop);
+    update_1word_crc32(crc, buf, table, 0, 0, crc, t1, t2, t3);
+    update_1word_crc32(crc, buf, table, 4, mainLoop_stepping, crc, t1, t2, t3);
+    z_brct(ctr, L_mainLoop);    // Iterate.
+
+  z_lrvr(crc, crc);        // Revert byte order back to original.
+
+  // Process last few (<8) bytes of buffer.
+  BIND(L_tail);
+  update_byteLoop_crc32(crc, buf, len, table, data, false);
+
+  not_(crc, noreg, false); // 1s complement of crc
+}
+
+/**
+ * @param crc   register containing existing CRC (32-bit)
+ * @param buf   register pointing to input byte buffer (byte*)
+ * @param len   register containing number of bytes
+ * @param table register pointing to CRC table
+ *
+ * uses Z_R10..Z_R13 as work register. Must be saved/restored by caller!
+ */
+void MacroAssembler::kernel_crc32_1word(Register crc, Register buf, Register len, Register table,
+                                        Register t0,  Register t1,  Register t2,  Register t3) {
+  assert_different_registers(crc, buf, len, table);
+
+  Label L_mainLoop, L_tail;
+  Register  data = t0;
+  Register  ctr  = Z_R0;
+  const int mainLoop_stepping = 4;
+  const int log_stepping      = exact_log2(mainLoop_stepping);
+
+  // Don't test for len <= 0 here. This pathological case should not occur anyway.
+  // Optimizing for it by adding a test and a branch seems to be a waste of CPU cycles.
+  // The situation itself is detected and handled correctly by the conditional branches
+  // following aghi(len, -stepping) and aghi(len, +stepping).
+
+  not_(crc, noreg, false); // 1s complement of crc
+
+  // Check for short (<4 bytes) buffer.
+  z_srag(ctr, len, log_stepping);
+  z_brnh(L_tail);
+
+  z_lrvr(crc, crc);          // Revert byte order because we are dealing with big-endian data.
+  rotate_then_insert(len, len, 64-log_stepping, 63, 0, true); // #bytes for tailLoop
+
+  BIND(L_mainLoop);
+    update_1word_crc32(crc, buf, table, 0, mainLoop_stepping, crc, t1, t2, t3);
+    z_brct(ctr, L_mainLoop); // Iterate.
+  z_lrvr(crc, crc);          // Revert byte order back to original.
+
+  // Process last few (<8) bytes of buffer.
+  BIND(L_tail);
+  update_byteLoop_crc32(crc, buf, len, table, data, false);
+
+  not_(crc, noreg, false); // 1s complement of crc
+}
+
+/**
+ * @param crc   register containing existing CRC (32-bit)
+ * @param buf   register pointing to input byte buffer (byte*)
+ * @param len   register containing number of bytes
+ * @param table register pointing to CRC table
+ */
+void MacroAssembler::kernel_crc32_1byte(Register crc, Register buf, Register len, Register table,
+                                        Register t0,  Register t1,  Register t2,  Register t3) {
+  assert_different_registers(crc, buf, len, table);
+  Register data = t0;
+
+  update_byteLoop_crc32(crc, buf, len, table, data, true);
+}
+
+void MacroAssembler::kernel_crc32_singleByte(Register crc, Register buf, Register len, Register table, Register tmp) {
+  assert_different_registers(crc, buf, len, table, tmp);
+
+  not_(crc, noreg, false); // ~c
+
+  z_llgc(tmp, Address(buf, (intptr_t)0));  // Current byte of input buffer (zero extended). Avoids garbage in upper half of register.
+  update_byte_crc32(crc, tmp, table);
+
+  not_(crc, noreg, false); // ~c
+}
+
+//
+// Code for BigInteger::multiplyToLen() intrinsic.
+//
+
+// dest_lo += src1 + src2
+// dest_hi += carry1 + carry2
+// Z_R7 is destroyed !
+void MacroAssembler::add2_with_carry(Register dest_hi, Register dest_lo,
+                                     Register src1, Register src2) {
+  clear_reg(Z_R7);
+  z_algr(dest_lo, src1);
+  z_alcgr(dest_hi, Z_R7);
+  z_algr(dest_lo, src2);
+  z_alcgr(dest_hi, Z_R7);
+}
+
+// Multiply 64 bit by 64 bit first loop.
+void MacroAssembler::multiply_64_x_64_loop(Register x, Register xstart,
+                                           Register x_xstart,
+                                           Register y, Register y_idx,
+                                           Register z,
+                                           Register carry,
+                                           Register product,
+                                           Register idx, Register kdx) {
+  // jlong carry, x[], y[], z[];
+  // for (int idx=ystart, kdx=ystart+1+xstart; idx >= 0; idx--, kdx--) {
+  //   huge_128 product = y[idx] * x[xstart] + carry;
+  //   z[kdx] = (jlong)product;
+  //   carry  = (jlong)(product >>> 64);
+  // }
+  // z[xstart] = carry;
+
+  Label L_first_loop, L_first_loop_exit;
+  Label L_one_x, L_one_y, L_multiply;
+
+  z_aghi(xstart, -1);
+  z_brl(L_one_x);   // Special case: length of x is 1.
+
+  // Load next two integers of x.
+  z_sllg(Z_R1_scratch, xstart, LogBytesPerInt);
+  mem2reg_opt(x_xstart, Address(x, Z_R1_scratch, 0));
+
+
+  bind(L_first_loop);
+
+  z_aghi(idx, -1);
+  z_brl(L_first_loop_exit);
+  z_aghi(idx, -1);
+  z_brl(L_one_y);
+
+  // Load next two integers of y.
+  z_sllg(Z_R1_scratch, idx, LogBytesPerInt);
+  mem2reg_opt(y_idx, Address(y, Z_R1_scratch, 0));
+
+
+  bind(L_multiply);
+
+  Register multiplicand = product->successor();
+  Register product_low = multiplicand;
+
+  lgr_if_needed(multiplicand, x_xstart);
+  z_mlgr(product, y_idx);     // multiplicand * y_idx -> product::multiplicand
+  clear_reg(Z_R7);
+  z_algr(product_low, carry); // Add carry to result.
+  z_alcgr(product, Z_R7);     // Add carry of the last addition.
+  add2reg(kdx, -2);
+
+  // Store result.
+  z_sllg(Z_R7, kdx, LogBytesPerInt);
+  reg2mem_opt(product_low, Address(z, Z_R7, 0));
+  lgr_if_needed(carry, product);
+  z_bru(L_first_loop);
+
+
+  bind(L_one_y); // Load one 32 bit portion of y as (0,value).
+
+  clear_reg(y_idx);
+  mem2reg_opt(y_idx, Address(y, (intptr_t) 0), false);
+  z_bru(L_multiply);
+
+
+  bind(L_one_x); // Load one 32 bit portion of x as (0,value).
+
+  clear_reg(x_xstart);
+  mem2reg_opt(x_xstart, Address(x, (intptr_t) 0), false);
+  z_bru(L_first_loop);
+
+  bind(L_first_loop_exit);
+}
+
+// Multiply 64 bit by 64 bit and add 128 bit.
+void MacroAssembler::multiply_add_128_x_128(Register x_xstart, Register y,
+                                            Register z,
+                                            Register yz_idx, Register idx,
+                                            Register carry, Register product,
+                                            int offset) {
+  // huge_128 product = (y[idx] * x_xstart) + z[kdx] + carry;
+  // z[kdx] = (jlong)product;
+
+  Register multiplicand = product->successor();
+  Register product_low = multiplicand;
+
+  z_sllg(Z_R7, idx, LogBytesPerInt);
+  mem2reg_opt(yz_idx, Address(y, Z_R7, offset));
+
+  lgr_if_needed(multiplicand, x_xstart);
+  z_mlgr(product, yz_idx); // multiplicand * yz_idx -> product::multiplicand
+  mem2reg_opt(yz_idx, Address(z, Z_R7, offset));
+
+  add2_with_carry(product, product_low, carry, yz_idx);
+
+  z_sllg(Z_R7, idx, LogBytesPerInt);
+  reg2mem_opt(product_low, Address(z, Z_R7, offset));
+
+}
+
+// Multiply 128 bit by 128 bit. Unrolled inner loop.
+void MacroAssembler::multiply_128_x_128_loop(Register x_xstart,
+                                             Register y, Register z,
+                                             Register yz_idx, Register idx,
+                                             Register jdx,
+                                             Register carry, Register product,
+                                             Register carry2) {
+  // jlong carry, x[], y[], z[];
+  // int kdx = ystart+1;
+  // for (int idx=ystart-2; idx >= 0; idx -= 2) { // Third loop
+  //   huge_128 product = (y[idx+1] * x_xstart) + z[kdx+idx+1] + carry;
+  //   z[kdx+idx+1] = (jlong)product;
+  //   jlong carry2 = (jlong)(product >>> 64);
+  //   product = (y[idx] * x_xstart) + z[kdx+idx] + carry2;
+  //   z[kdx+idx] = (jlong)product;
+  //   carry = (jlong)(product >>> 64);
+  // }
+  // idx += 2;
+  // if (idx > 0) {
+  //   product = (y[idx] * x_xstart) + z[kdx+idx] + carry;
+  //   z[kdx+idx] = (jlong)product;
+  //   carry = (jlong)(product >>> 64);
+  // }
+
+  Label L_third_loop, L_third_loop_exit, L_post_third_loop_done;
+
+  // scale the index
+  lgr_if_needed(jdx, idx);
+  and_imm(jdx, 0xfffffffffffffffcL);
+  rshift(jdx, 2);
+
+
+  bind(L_third_loop);
+
+  z_aghi(jdx, -1);
+  z_brl(L_third_loop_exit);
+  add2reg(idx, -4);
+
+  multiply_add_128_x_128(x_xstart, y, z, yz_idx, idx, carry, product, 8);
+  lgr_if_needed(carry2, product);
+
+  multiply_add_128_x_128(x_xstart, y, z, yz_idx, idx, carry2, product, 0);
+  lgr_if_needed(carry, product);
+  z_bru(L_third_loop);
+
+
+  bind(L_third_loop_exit);  // Handle any left-over operand parts.
+
+  and_imm(idx, 0x3);
+  z_brz(L_post_third_loop_done);
+
+  Label L_check_1;
+
+  z_aghi(idx, -2);
+  z_brl(L_check_1);
+
+  multiply_add_128_x_128(x_xstart, y, z, yz_idx, idx, carry, product, 0);
+  lgr_if_needed(carry, product);
+
+
+  bind(L_check_1);
+
+  add2reg(idx, 0x2);
+  and_imm(idx, 0x1);
+  z_aghi(idx, -1);
+  z_brl(L_post_third_loop_done);
+
+  Register   multiplicand = product->successor();
+  Register   product_low = multiplicand;
+
+  z_sllg(Z_R7, idx, LogBytesPerInt);
+  clear_reg(yz_idx);
+  mem2reg_opt(yz_idx, Address(y, Z_R7, 0), false);
+  lgr_if_needed(multiplicand, x_xstart);
+  z_mlgr(product, yz_idx); // multiplicand * yz_idx -> product::multiplicand
+  clear_reg(yz_idx);
+  mem2reg_opt(yz_idx, Address(z, Z_R7, 0), false);
+
+  add2_with_carry(product, product_low, yz_idx, carry);
+
+  z_sllg(Z_R7, idx, LogBytesPerInt);
+  reg2mem_opt(product_low, Address(z, Z_R7, 0), false);
+  rshift(product_low, 32);
+
+  lshift(product, 32);
+  z_ogr(product_low, product);
+  lgr_if_needed(carry, product_low);
+
+  bind(L_post_third_loop_done);
+}
+
+void MacroAssembler::multiply_to_len(Register x, Register xlen,
+                                     Register y, Register ylen,
+                                     Register z,
+                                     Register tmp1, Register tmp2,
+                                     Register tmp3, Register tmp4,
+                                     Register tmp5) {
+  ShortBranchVerifier sbv(this);
+
+  assert_different_registers(x, xlen, y, ylen, z,
+                             tmp1, tmp2, tmp3, tmp4, tmp5, Z_R1_scratch, Z_R7);
+  assert_different_registers(x, xlen, y, ylen, z,
+                             tmp1, tmp2, tmp3, tmp4, tmp5, Z_R8);
+
+  z_stmg(Z_R7, Z_R13, _z_abi(gpr7), Z_SP);
+
+  // In openJdk, we store the argument as 32-bit value to slot.
+  Address zlen(Z_SP, _z_abi(remaining_cargs));  // Int in long on big endian.
+
+  const Register idx = tmp1;
+  const Register kdx = tmp2;
+  const Register xstart = tmp3;
+
+  const Register y_idx = tmp4;
+  const Register carry = tmp5;
+  const Register product  = Z_R0_scratch;
+  const Register x_xstart = Z_R8;
+
+  // First Loop.
+  //
+  //   final static long LONG_MASK = 0xffffffffL;
+  //   int xstart = xlen - 1;
+  //   int ystart = ylen - 1;
+  //   long carry = 0;
+  //   for (int idx=ystart, kdx=ystart+1+xstart; idx >= 0; idx-, kdx--) {
+  //     long product = (y[idx] & LONG_MASK) * (x[xstart] & LONG_MASK) + carry;
+  //     z[kdx] = (int)product;
+  //     carry = product >>> 32;
+  //   }
+  //   z[xstart] = (int)carry;
+  //
+
+  lgr_if_needed(idx, ylen);  // idx = ylen
+  z_llgf(kdx, zlen);         // C2 does not respect int to long conversion for stub calls, thus load zero-extended.
+  clear_reg(carry);          // carry = 0
+
+  Label L_done;
+
+  lgr_if_needed(xstart, xlen);
+  z_aghi(xstart, -1);
+  z_brl(L_done);
+
+  multiply_64_x_64_loop(x, xstart, x_xstart, y, y_idx, z, carry, product, idx, kdx);
+
+  NearLabel L_second_loop;
+  compare64_and_branch(kdx, RegisterOrConstant((intptr_t) 0), bcondEqual, L_second_loop);
+
+  NearLabel L_carry;
+  z_aghi(kdx, -1);
+  z_brz(L_carry);
+
+  // Store lower 32 bits of carry.
+  z_sllg(Z_R1_scratch, kdx, LogBytesPerInt);
+  reg2mem_opt(carry, Address(z, Z_R1_scratch, 0), false);
+  rshift(carry, 32);
+  z_aghi(kdx, -1);
+
+
+  bind(L_carry);
+
+  // Store upper 32 bits of carry.
+  z_sllg(Z_R1_scratch, kdx, LogBytesPerInt);
+  reg2mem_opt(carry, Address(z, Z_R1_scratch, 0), false);
+
+  // Second and third (nested) loops.
+  //
+  // for (int i = xstart-1; i >= 0; i--) { // Second loop
+  //   carry = 0;
+  //   for (int jdx=ystart, k=ystart+1+i; jdx >= 0; jdx--, k--) { // Third loop
+  //     long product = (y[jdx] & LONG_MASK) * (x[i] & LONG_MASK) +
+  //                    (z[k] & LONG_MASK) + carry;
+  //     z[k] = (int)product;
+  //     carry = product >>> 32;
+  //   }
+  //   z[i] = (int)carry;
+  // }
+  //
+  // i = xlen, j = tmp1, k = tmp2, carry = tmp5, x[i] = rdx
+
+  const Register jdx = tmp1;
+
+  bind(L_second_loop);
+
+  clear_reg(carry);           // carry = 0;
+  lgr_if_needed(jdx, ylen);   // j = ystart+1
+
+  z_aghi(xstart, -1);         // i = xstart-1;
+  z_brl(L_done);
+
+  // Use free slots in the current stackframe instead of push/pop.
+  Address zsave(Z_SP, _z_abi(carg_1));
+  reg2mem_opt(z, zsave);
+
+
+  Label L_last_x;
+
+  z_sllg(Z_R1_scratch, xstart, LogBytesPerInt);
+  load_address(z, Address(z, Z_R1_scratch, 4)); // z = z + k - j
+  z_aghi(xstart, -1);                           // i = xstart-1;
+  z_brl(L_last_x);
+
+  z_sllg(Z_R1_scratch, xstart, LogBytesPerInt);
+  mem2reg_opt(x_xstart, Address(x, Z_R1_scratch, 0));
+
+
+  Label L_third_loop_prologue;
+
+  bind(L_third_loop_prologue);
+
+  Address xsave(Z_SP, _z_abi(carg_2));
+  Address xlensave(Z_SP, _z_abi(carg_3));
+  Address ylensave(Z_SP, _z_abi(carg_4));
+
+  reg2mem_opt(x, xsave);
+  reg2mem_opt(xstart, xlensave);
+  reg2mem_opt(ylen, ylensave);
+
+
+  multiply_128_x_128_loop(x_xstart, y, z, y_idx, jdx, ylen, carry, product, x);
+
+  mem2reg_opt(z, zsave);
+  mem2reg_opt(x, xsave);
+  mem2reg_opt(xlen, xlensave);   // This is the decrement of the loop counter!
+  mem2reg_opt(ylen, ylensave);
+
+  add2reg(tmp3, 1, xlen);
+  z_sllg(Z_R1_scratch, tmp3, LogBytesPerInt);
+  reg2mem_opt(carry, Address(z, Z_R1_scratch, 0), false);
+  z_aghi(tmp3, -1);
+  z_brl(L_done);
+
+  rshift(carry, 32);
+  z_sllg(Z_R1_scratch, tmp3, LogBytesPerInt);
+  reg2mem_opt(carry, Address(z, Z_R1_scratch, 0), false);
+  z_bru(L_second_loop);
+
+  // Next infrequent code is moved outside loops.
+  bind(L_last_x);
+
+  clear_reg(x_xstart);
+  mem2reg_opt(x_xstart, Address(x, (intptr_t) 0), false);
+  z_bru(L_third_loop_prologue);
+
+  bind(L_done);
+
+  z_lmg(Z_R7, Z_R13, _z_abi(gpr7), Z_SP);
+}
+
+#ifndef PRODUCT
+// Assert if CC indicates "not equal" (check_equal==true) or "equal" (check_equal==false).
+void MacroAssembler::asm_assert(bool check_equal, const char *msg, int id) {
+  Label ok;
+  if (check_equal) {
+    z_bre(ok);
+  } else {
+    z_brne(ok);
+  }
+  stop(msg, id);
+  bind(ok);
+}
+
+// Assert if CC indicates "low".
+void MacroAssembler::asm_assert_low(const char *msg, int id) {
+  Label ok;
+  z_brnl(ok);
+  stop(msg, id);
+  bind(ok);
+}
+
+// Assert if CC indicates "high".
+void MacroAssembler::asm_assert_high(const char *msg, int id) {
+  Label ok;
+  z_brnh(ok);
+  stop(msg, id);
+  bind(ok);
+}
+
+// Assert if CC indicates "not equal" (check_equal==true) or "equal" (check_equal==false)
+// generate non-relocatable code.
+void MacroAssembler::asm_assert_static(bool check_equal, const char *msg, int id) {
+  Label ok;
+  if (check_equal) { z_bre(ok); }
+  else             { z_brne(ok); }
+  stop_static(msg, id);
+  bind(ok);
+}
+
+void MacroAssembler::asm_assert_mems_zero(bool check_equal, bool allow_relocation, int size, int64_t mem_offset,
+                                          Register mem_base, const char* msg, int id) {
+  switch (size) {
+    case 4:
+      load_and_test_int(Z_R0, Address(mem_base, mem_offset));
+      break;
+    case 8:
+      load_and_test_long(Z_R0,  Address(mem_base, mem_offset));
+      break;
+    default:
+      ShouldNotReachHere();
+  }
+  if (allow_relocation) { asm_assert(check_equal, msg, id); }
+  else                  { asm_assert_static(check_equal, msg, id); }
+}
+
+// Check the condition
+//   expected_size == FP - SP
+// after transformation:
+//   expected_size - FP + SP == 0
+// Destroys Register expected_size if no tmp register is passed.
+void MacroAssembler::asm_assert_frame_size(Register expected_size, Register tmp, const char* msg, int id) {
+  if (tmp == noreg) {
+    tmp = expected_size;
+  } else {
+    if (tmp != expected_size) {
+      z_lgr(tmp, expected_size);
+    }
+    z_algr(tmp, Z_SP);
+    z_slg(tmp, 0, Z_R0, Z_SP);
+    asm_assert_eq(msg, id);
+  }
+}
+#endif // !PRODUCT
+
+void MacroAssembler::verify_thread() {
+  if (VerifyThread) {
+    unimplemented("", 117);
+  }
+}
+
+// Plausibility check for oops.
+void MacroAssembler::verify_oop(Register oop, const char* msg) {
+  if (!VerifyOops) return;
+
+  BLOCK_COMMENT("verify_oop {");
+  Register tmp = Z_R0;
+  unsigned int nbytes_save = 6 *8;
+  address entry = StubRoutines::verify_oop_subroutine_entry_address();
+  save_return_pc();
+  push_frame_abi160(nbytes_save);
+  z_stmg(Z_R0, Z_R5, 160, Z_SP);
+
+  z_lgr(Z_ARG2, oop);
+  load_const(Z_ARG1, (address) msg);
+  load_const(Z_R1, entry);
+  z_lg(Z_R1, 0, Z_R1);
+  call_c(Z_R1);
+
+  z_lmg(Z_R0, Z_R5, 160, Z_SP);
+  pop_frame();
+
+  restore_return_pc();
+  BLOCK_COMMENT("} verify_oop ");
+}
+
+const char* MacroAssembler::stop_types[] = {
+  "stop",
+  "untested",
+  "unimplemented",
+  "shouldnotreachhere"
+};
+
+static void stop_on_request(const char* tp, const char* msg) {
+  tty->print("Z assembly code requires stop: (%s) %s\n", tp, msg);
+  guarantee(false, "Z assembly code requires stop: %s", msg);
+}
+
+void MacroAssembler::stop(int type, const char* msg, int id) {
+  BLOCK_COMMENT(err_msg("stop: %s {", msg));
+
+  // Setup arguments.
+  load_const(Z_ARG1, (void*) stop_types[type%stop_end]);
+  load_const(Z_ARG2, (void*) msg);
+  get_PC(Z_R14); // Following code pushes a frame without entering a new function. Use current pc as return address.
+  save_return_pc();    // Saves return pc Z_R14.
+  push_frame_abi160(0);
+  call_VM_leaf(CAST_FROM_FN_PTR(address, stop_on_request), Z_ARG1, Z_ARG2);
+  // The plain disassembler does not recognize illtrap. It instead displays
+  // a 32-bit value. Issueing two illtraps assures the disassembler finds
+  // the proper beginning of the next instruction.
+  z_illtrap(); // Illegal instruction.
+  z_illtrap(); // Illegal instruction.
+
+  BLOCK_COMMENT(" } stop");
+}
+
+// Special version of stop() for code size reduction.
+// Reuses the previously generated call sequence, if any.
+// Generates the call sequence on its own, if necessary.
+// Note: This code will work only in non-relocatable code!
+//       The relative address of the data elements (arg1, arg2) must not change.
+//       The reentry point must not move relative to it's users. This prerequisite
+//       should be given for "hand-written" code, if all chain calls are in the same code blob.
+//       Generated code must not undergo any transformation, e.g. ShortenBranches, to be safe.
+address MacroAssembler::stop_chain(address reentry, int type, const char* msg, int id, bool allow_relocation) {
+  BLOCK_COMMENT(err_msg("stop_chain(%s,%s): %s {", reentry==NULL?"init":"cont", allow_relocation?"reloc ":"static", msg));
+
+  // Setup arguments.
+  if (allow_relocation) {
+    // Relocatable version (for comparison purposes). Remove after some time.
+    load_const(Z_ARG1, (void*) stop_types[type%stop_end]);
+    load_const(Z_ARG2, (void*) msg);
+  } else {
+    load_absolute_address(Z_ARG1, (address)stop_types[type%stop_end]);
+    load_absolute_address(Z_ARG2, (address)msg);
+  }
+  if ((reentry != NULL) && RelAddr::is_in_range_of_RelAddr16(reentry, pc())) {
+    BLOCK_COMMENT("branch to reentry point:");
+    z_brc(bcondAlways, reentry);
+  } else {
+    BLOCK_COMMENT("reentry point:");
+    reentry = pc();      // Re-entry point for subsequent stop calls.
+    save_return_pc();    // Saves return pc Z_R14.
+    push_frame_abi160(0);
+    if (allow_relocation) {
+      reentry = NULL;    // Prevent reentry if code relocation is allowed.
+      call_VM_leaf(CAST_FROM_FN_PTR(address, stop_on_request), Z_ARG1, Z_ARG2);
+    } else {
+      call_VM_leaf_static(CAST_FROM_FN_PTR(address, stop_on_request), Z_ARG1, Z_ARG2);
+    }
+    z_illtrap(); // Illegal instruction as emergency stop, should the above call return.
+  }
+  BLOCK_COMMENT(" } stop_chain");
+
+  return reentry;
+}
+
+// Special version of stop() for code size reduction.
+// Assumes constant relative addresses for data and runtime call.
+void MacroAssembler::stop_static(int type, const char* msg, int id) {
+  stop_chain(NULL, type, msg, id, false);
+}
+
+void MacroAssembler::stop_subroutine() {
+  unimplemented("stop_subroutine", 710);
+}
+
+// Prints msg to stdout from within generated code..
+void MacroAssembler::warn(const char* msg) {
+  RegisterSaver::save_live_registers(this, RegisterSaver::all_registers, Z_R14);
+  load_absolute_address(Z_R1, (address) warning);
+  load_absolute_address(Z_ARG1, (address) msg);
+  (void) call(Z_R1);
+  RegisterSaver::restore_live_registers(this, RegisterSaver::all_registers);
+}
+
+#ifndef PRODUCT
+
+// Write pattern 0x0101010101010101 in region [low-before, high+after].
+void MacroAssembler::zap_from_to(Register low, Register high, Register val, Register addr, int before, int after) {
+  if (!ZapEmptyStackFields) return;
+  BLOCK_COMMENT("zap memory region {");
+  load_const_optimized(val, 0x0101010101010101);
+  int size = before + after;
+  if (low == high && size < 5 && size > 0) {
+    int offset = -before*BytesPerWord;
+    for (int i = 0; i < size; ++i) {
+      z_stg(val, Address(low, offset));
+      offset +=(1*BytesPerWord);
+    }
+  } else {
+    add2reg(addr, -before*BytesPerWord, low);
+    if (after) {
+#ifdef ASSERT
+      jlong check = after * BytesPerWord;
+      assert(Immediate::is_simm32(check) && Immediate::is_simm32(-check), "value not encodable !");
+#endif
+      add2reg(high, after * BytesPerWord);
+    }
+    NearLabel loop;
+    bind(loop);
+    z_stg(val, Address(addr));
+    add2reg(addr, 8);
+    compare64_and_branch(addr, high, bcondNotHigh, loop);
+    if (after) {
+      add2reg(high, -after * BytesPerWord);
+    }
+  }
+  BLOCK_COMMENT("} zap memory region");
+}
+#endif // !PRODUCT
+
+SkipIfEqual::SkipIfEqual(MacroAssembler* masm, const bool* flag_addr, bool value, Register _rscratch) {
+  _masm = masm;
+  _masm->load_absolute_address(_rscratch, (address)flag_addr);
+  _masm->load_and_test_int(_rscratch, Address(_rscratch));
+  if (value) {
+    _masm->z_brne(_label); // Skip if true, i.e. != 0.
+  } else {
+    _masm->z_bre(_label);  // Skip if false, i.e. == 0.
+  }
+}
+
+SkipIfEqual::~SkipIfEqual() {
+  _masm->bind(_label);
+}