6800154: Add comments to long_by_long_mulhi() for better understandability
Summary: This patch adds a comment pointing to the Hacker's Delight version of the algorithm plus a verbatim copy of it. Furthermore it adds inline comments.
Reviewed-by: kvn, jrose
/*
* Copyright 1999-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
#include "incls/_precompiled.incl"
#include "incls/_c1_CodeStubs_sparc.cpp.incl"
#define __ ce->masm()->
RangeCheckStub::RangeCheckStub(CodeEmitInfo* info, LIR_Opr index,
bool throw_index_out_of_bounds_exception)
: _throw_index_out_of_bounds_exception(throw_index_out_of_bounds_exception)
, _index(index)
{
_info = new CodeEmitInfo(info);
}
void RangeCheckStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
if (_index->is_register()) {
__ mov(_index->as_register(), G4);
} else {
__ set(_index->as_jint(), G4);
}
if (_throw_index_out_of_bounds_exception) {
__ call(Runtime1::entry_for(Runtime1::throw_index_exception_id), relocInfo::runtime_call_type);
} else {
__ call(Runtime1::entry_for(Runtime1::throw_range_check_failed_id), relocInfo::runtime_call_type);
}
__ delayed()->nop();
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
#ifdef ASSERT
__ should_not_reach_here();
#endif
}
#ifdef TIERED
void CounterOverflowStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ set(_bci, G4);
__ call(Runtime1::entry_for(Runtime1::counter_overflow_id), relocInfo::runtime_call_type);
__ delayed()->nop();
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
__ br(Assembler::always, true, Assembler::pt, _continuation);
__ delayed()->nop();
}
#endif // TIERED
void DivByZeroStub::emit_code(LIR_Assembler* ce) {
if (_offset != -1) {
ce->compilation()->implicit_exception_table()->append(_offset, __ offset());
}
__ bind(_entry);
__ call(Runtime1::entry_for(Runtime1::throw_div0_exception_id), relocInfo::runtime_call_type);
__ delayed()->nop();
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
#ifdef ASSERT
__ should_not_reach_here();
#endif
}
void ImplicitNullCheckStub::emit_code(LIR_Assembler* ce) {
ce->compilation()->implicit_exception_table()->append(_offset, __ offset());
__ bind(_entry);
__ call(Runtime1::entry_for(Runtime1::throw_null_pointer_exception_id),
relocInfo::runtime_call_type);
__ delayed()->nop();
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
#ifdef ASSERT
__ should_not_reach_here();
#endif
}
// Implementation of SimpleExceptionStub
// Note: %g1 and %g3 are already in use
void SimpleExceptionStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ call(Runtime1::entry_for(_stub), relocInfo::runtime_call_type);
if (_obj->is_valid()) {
__ delayed()->mov(_obj->as_register(), G4); // _obj contains the optional argument to the stub
} else {
__ delayed()->mov(G0, G4);
}
ce->add_call_info_here(_info);
#ifdef ASSERT
__ should_not_reach_here();
#endif
}
// Implementation of ArrayStoreExceptionStub
ArrayStoreExceptionStub::ArrayStoreExceptionStub(CodeEmitInfo* info):
_info(info) {
}
void ArrayStoreExceptionStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ call(Runtime1::entry_for(Runtime1::throw_array_store_exception_id), relocInfo::runtime_call_type);
__ delayed()->nop();
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
#ifdef ASSERT
__ should_not_reach_here();
#endif
}
// Implementation of NewInstanceStub
NewInstanceStub::NewInstanceStub(LIR_Opr klass_reg, LIR_Opr result, ciInstanceKlass* klass, CodeEmitInfo* info, Runtime1::StubID stub_id) {
_result = result;
_klass = klass;
_klass_reg = klass_reg;
_info = new CodeEmitInfo(info);
assert(stub_id == Runtime1::new_instance_id ||
stub_id == Runtime1::fast_new_instance_id ||
stub_id == Runtime1::fast_new_instance_init_check_id,
"need new_instance id");
_stub_id = stub_id;
}
void NewInstanceStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ call(Runtime1::entry_for(_stub_id), relocInfo::runtime_call_type);
__ delayed()->mov_or_nop(_klass_reg->as_register(), G5);
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->mov_or_nop(O0, _result->as_register());
}
// Implementation of NewTypeArrayStub
NewTypeArrayStub::NewTypeArrayStub(LIR_Opr klass_reg, LIR_Opr length, LIR_Opr result, CodeEmitInfo* info) {
_klass_reg = klass_reg;
_length = length;
_result = result;
_info = new CodeEmitInfo(info);
}
void NewTypeArrayStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ mov(_length->as_register(), G4);
__ call(Runtime1::entry_for(Runtime1::new_type_array_id), relocInfo::runtime_call_type);
__ delayed()->mov_or_nop(_klass_reg->as_register(), G5);
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->mov_or_nop(O0, _result->as_register());
}
// Implementation of NewObjectArrayStub
NewObjectArrayStub::NewObjectArrayStub(LIR_Opr klass_reg, LIR_Opr length, LIR_Opr result, CodeEmitInfo* info) {
_klass_reg = klass_reg;
_length = length;
_result = result;
_info = new CodeEmitInfo(info);
}
void NewObjectArrayStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ mov(_length->as_register(), G4);
__ call(Runtime1::entry_for(Runtime1::new_object_array_id), relocInfo::runtime_call_type);
__ delayed()->mov_or_nop(_klass_reg->as_register(), G5);
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->mov_or_nop(O0, _result->as_register());
}
// Implementation of MonitorAccessStubs
MonitorEnterStub::MonitorEnterStub(LIR_Opr obj_reg, LIR_Opr lock_reg, CodeEmitInfo* info)
: MonitorAccessStub(obj_reg, lock_reg) {
_info = new CodeEmitInfo(info);
}
void MonitorEnterStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
__ mov(_obj_reg->as_register(), G4);
if (ce->compilation()->has_fpu_code()) {
__ call(Runtime1::entry_for(Runtime1::monitorenter_id), relocInfo::runtime_call_type);
} else {
__ call(Runtime1::entry_for(Runtime1::monitorenter_nofpu_id), relocInfo::runtime_call_type);
}
__ delayed()->mov_or_nop(_lock_reg->as_register(), G5);
ce->add_call_info_here(_info);
ce->verify_oop_map(_info);
__ br(Assembler::always, true, Assembler::pt, _continuation);
__ delayed()->nop();
}
void MonitorExitStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
if (_compute_lock) {
ce->monitor_address(_monitor_ix, _lock_reg);
}
if (ce->compilation()->has_fpu_code()) {
__ call(Runtime1::entry_for(Runtime1::monitorexit_id), relocInfo::runtime_call_type);
} else {
__ call(Runtime1::entry_for(Runtime1::monitorexit_nofpu_id), relocInfo::runtime_call_type);
}
__ delayed()->mov_or_nop(_lock_reg->as_register(), G4);
__ br(Assembler::always, true, Assembler::pt, _continuation);
__ delayed()->nop();
}
// Implementation of patching:
// - Copy the code at given offset to an inlined buffer (first the bytes, then the number of bytes)
// - Replace original code with a call to the stub
// At Runtime:
// - call to stub, jump to runtime
// - in runtime: preserve all registers (especially objects, i.e., source and destination object)
// - in runtime: after initializing class, restore original code, reexecute instruction
int PatchingStub::_patch_info_offset = -NativeGeneralJump::instruction_size;
void PatchingStub::align_patch_site(MacroAssembler* ) {
// patch sites on sparc are always properly aligned.
}
void PatchingStub::emit_code(LIR_Assembler* ce) {
// copy original code here
assert(NativeCall::instruction_size <= _bytes_to_copy && _bytes_to_copy <= 0xFF,
"not enough room for call");
assert((_bytes_to_copy & 0x3) == 0, "must copy a multiple of four bytes");
Label call_patch;
int being_initialized_entry = __ offset();
if (_id == load_klass_id) {
// produce a copy of the load klass instruction for use by the being initialized case
address start = __ pc();
Address addr = Address(_obj, address(NULL), oop_Relocation::spec(_oop_index));
__ sethi(addr, true);
__ add(addr, _obj, 0);
#ifdef ASSERT
for (int i = 0; i < _bytes_to_copy; i++) {
address ptr = (address)(_pc_start + i);
int a_byte = (*ptr) & 0xFF;
assert(a_byte == *start++, "should be the same code");
}
#endif
} else {
// make a copy the code which is going to be patched.
for (int i = 0; i < _bytes_to_copy; i++) {
address ptr = (address)(_pc_start + i);
int a_byte = (*ptr) & 0xFF;
__ a_byte (a_byte);
}
}
address end_of_patch = __ pc();
int bytes_to_skip = 0;
if (_id == load_klass_id) {
int offset = __ offset();
if (CommentedAssembly) {
__ block_comment(" being_initialized check");
}
// static field accesses have special semantics while the class
// initializer is being run so we emit a test which can be used to
// check that this code is being executed by the initializing
// thread.
assert(_obj != noreg, "must be a valid register");
assert(_oop_index >= 0, "must have oop index");
__ ld_ptr(_obj, instanceKlass::init_thread_offset_in_bytes() + sizeof(klassOopDesc), G3);
__ cmp(G2_thread, G3);
__ br(Assembler::notEqual, false, Assembler::pn, call_patch);
__ delayed()->nop();
// load_klass patches may execute the patched code before it's
// copied back into place so we need to jump back into the main
// code of the nmethod to continue execution.
__ br(Assembler::always, false, Assembler::pt, _patch_site_continuation);
__ delayed()->nop();
// make sure this extra code gets skipped
bytes_to_skip += __ offset() - offset;
}
// Now emit the patch record telling the runtime how to find the
// pieces of the patch. We only need 3 bytes but it has to be
// aligned as an instruction so emit 4 bytes.
int sizeof_patch_record = 4;
bytes_to_skip += sizeof_patch_record;
// emit the offsets needed to find the code to patch
int being_initialized_entry_offset = __ offset() - being_initialized_entry + sizeof_patch_record;
// Emit the patch record. We need to emit a full word, so emit an extra empty byte
__ a_byte(0);
__ a_byte(being_initialized_entry_offset);
__ a_byte(bytes_to_skip);
__ a_byte(_bytes_to_copy);
address patch_info_pc = __ pc();
assert(patch_info_pc - end_of_patch == bytes_to_skip, "incorrect patch info");
address entry = __ pc();
NativeGeneralJump::insert_unconditional((address)_pc_start, entry);
address target = NULL;
switch (_id) {
case access_field_id: target = Runtime1::entry_for(Runtime1::access_field_patching_id); break;
case load_klass_id: target = Runtime1::entry_for(Runtime1::load_klass_patching_id); break;
default: ShouldNotReachHere();
}
__ bind(call_patch);
if (CommentedAssembly) {
__ block_comment("patch entry point");
}
__ call(target, relocInfo::runtime_call_type);
__ delayed()->nop();
assert(_patch_info_offset == (patch_info_pc - __ pc()), "must not change");
ce->add_call_info_here(_info);
__ br(Assembler::always, false, Assembler::pt, _patch_site_entry);
__ delayed()->nop();
if (_id == load_klass_id) {
CodeSection* cs = __ code_section();
address pc = (address)_pc_start;
RelocIterator iter(cs, pc, pc + 1);
relocInfo::change_reloc_info_for_address(&iter, (address) pc, relocInfo::oop_type, relocInfo::none);
pc = (address)(_pc_start + NativeMovConstReg::add_offset);
RelocIterator iter2(cs, pc, pc+1);
relocInfo::change_reloc_info_for_address(&iter2, (address) pc, relocInfo::oop_type, relocInfo::none);
}
}
void ArrayCopyStub::emit_code(LIR_Assembler* ce) {
//---------------slow case: call to native-----------------
__ bind(_entry);
__ mov(src()->as_register(), O0);
__ mov(src_pos()->as_register(), O1);
__ mov(dst()->as_register(), O2);
__ mov(dst_pos()->as_register(), O3);
__ mov(length()->as_register(), O4);
ce->emit_static_call_stub();
__ call(SharedRuntime::get_resolve_static_call_stub(), relocInfo::static_call_type);
__ delayed()->nop();
ce->add_call_info_here(info());
ce->verify_oop_map(info());
#ifndef PRODUCT
__ set((intptr_t)&Runtime1::_arraycopy_slowcase_cnt, O0);
__ ld(O0, 0, O1);
__ inc(O1);
__ st(O1, 0, O0);
#endif
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->nop();
}
///////////////////////////////////////////////////////////////////////////////////
#ifndef SERIALGC
void G1PreBarrierStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
assert(pre_val()->is_register(), "Precondition.");
Register pre_val_reg = pre_val()->as_register();
ce->mem2reg(addr(), pre_val(), T_OBJECT, patch_code(), info(), false);
__ br_on_reg_cond(Assembler::rc_z, /*annul*/false, Assembler::pt,
pre_val_reg, _continuation);
__ delayed()->nop();
__ call(Runtime1::entry_for(Runtime1::Runtime1::g1_pre_barrier_slow_id));
__ delayed()->mov(pre_val_reg, G4);
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->nop();
}
jbyte* G1PostBarrierStub::_byte_map_base = NULL;
jbyte* G1PostBarrierStub::byte_map_base_slow() {
BarrierSet* bs = Universe::heap()->barrier_set();
assert(bs->is_a(BarrierSet::G1SATBCTLogging),
"Must be if we're using this.");
return ((G1SATBCardTableModRefBS*)bs)->byte_map_base;
}
void G1PostBarrierStub::emit_code(LIR_Assembler* ce) {
__ bind(_entry);
assert(addr()->is_register(), "Precondition.");
assert(new_val()->is_register(), "Precondition.");
Register addr_reg = addr()->as_pointer_register();
Register new_val_reg = new_val()->as_register();
__ br_on_reg_cond(Assembler::rc_z, /*annul*/false, Assembler::pt,
new_val_reg, _continuation);
__ delayed()->nop();
__ call(Runtime1::entry_for(Runtime1::Runtime1::g1_post_barrier_slow_id));
__ delayed()->mov(addr_reg, G4);
__ br(Assembler::always, false, Assembler::pt, _continuation);
__ delayed()->nop();
}
#endif // SERIALGC
///////////////////////////////////////////////////////////////////////////////////
#undef __