hotspot/src/share/vm/utilities/copy.cpp
changeset 1 489c9b5090e2
child 5547 f4b087cbb361
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/utilities/copy.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2006-2007 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/_copy.cpp.incl"
+
+
+// Copy bytes; larger units are filled atomically if everything is aligned.
+void Copy::conjoint_memory_atomic(void* from, void* to, size_t size) {
+  address src = (address) from;
+  address dst = (address) to;
+  uintptr_t bits = (uintptr_t) src | (uintptr_t) dst | (uintptr_t) size;
+
+  // (Note:  We could improve performance by ignoring the low bits of size,
+  // and putting a short cleanup loop after each bulk copy loop.
+  // There are plenty of other ways to make this faster also,
+  // and it's a slippery slope.  For now, let's keep this code simple
+  // since the simplicity helps clarify the atomicity semantics of
+  // this operation.  There are also CPU-specific assembly versions
+  // which may or may not want to include such optimizations.)
+
+  if (bits % sizeof(jlong) == 0) {
+    Copy::conjoint_jlongs_atomic((jlong*) src, (jlong*) dst, size / sizeof(jlong));
+  } else if (bits % sizeof(jint) == 0) {
+    Copy::conjoint_jints_atomic((jint*) src, (jint*) dst, size / sizeof(jint));
+  } else if (bits % sizeof(jshort) == 0) {
+    Copy::conjoint_jshorts_atomic((jshort*) src, (jshort*) dst, size / sizeof(jshort));
+  } else {
+    // Not aligned, so no need to be atomic.
+    Copy::conjoint_bytes((void*) src, (void*) dst, size);
+  }
+}
+
+
+// Fill bytes; larger units are filled atomically if everything is aligned.
+void Copy::fill_to_memory_atomic(void* to, size_t size, jubyte value) {
+  address dst = (address) to;
+  uintptr_t bits = (uintptr_t) to | (uintptr_t) size;
+  if (bits % sizeof(jlong) == 0) {
+    jlong fill = (julong)( (jubyte)value ); // zero-extend
+    if (fill != 0) {
+      fill += fill << 8;
+      fill += fill << 16;
+      fill += fill << 32;
+    }
+    //Copy::fill_to_jlongs_atomic((jlong*) dst, size / sizeof(jlong));
+    for (uintptr_t off = 0; off < size; off += sizeof(jlong)) {
+      *(jlong*)(dst + off) = fill;
+    }
+  } else if (bits % sizeof(jint) == 0) {
+    jint fill = (juint)( (jubyte)value ); // zero-extend
+    if (fill != 0) {
+      fill += fill << 8;
+      fill += fill << 16;
+    }
+    //Copy::fill_to_jints_atomic((jint*) dst, size / sizeof(jint));
+    for (uintptr_t off = 0; off < size; off += sizeof(jint)) {
+      *(jint*)(dst + off) = fill;
+    }
+  } else if (bits % sizeof(jshort) == 0) {
+    jshort fill = (jushort)( (jubyte)value ); // zero-extend
+    fill += fill << 8;
+    //Copy::fill_to_jshorts_atomic((jshort*) dst, size / sizeof(jshort));
+    for (uintptr_t off = 0; off < size; off += sizeof(jshort)) {
+      *(jshort*)(dst + off) = fill;
+    }
+  } else {
+    // Not aligned, so no need to be atomic.
+    Copy::fill_to_bytes(dst, size, value);
+  }
+}