--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/os_cpu/windows_x86/vm/assembler_windows_x86_32.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,64 @@
+/*
+ * Copyright 1999-2003 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/_assembler_windows_x86_32.cpp.incl"
+
+
+void MacroAssembler::int3() {
+  emit_byte(0xCC);
+}
+
+//  The current scheme to accelerate access to the thread
+//  pointer is to store the current thread in the os_exception_wrapper
+//  and reference the current thread from stubs and compiled code
+//  via the FS register.  FS[0] contains a pointer to the structured
+//  exception block which is actually a stack address.  The first time
+//  we call the os exception wrapper, we calculate and store the
+//  offset from this exception block and use that offset here.
+//
+//  The last mechanism we used was problematic in that the
+//  the offset we had hard coded in the VM kept changing as Microsoft
+//  evolved the OS.
+//
+// Warning: This mechanism assumes that we only attempt to get the
+//          thread when we are nested below a call wrapper.
+//
+// movl reg, fs:[0]                        Get exeception pointer
+// movl reg, [reg + thread_ptr_offset]     Load thread
+//
+void MacroAssembler::get_thread(Register thread) {
+  // can't use ExternalAddress because it can't take NULL
+  AddressLiteral null(0, relocInfo::none);
+
+  prefix(FS_segment);
+  movptr(thread, null);
+  assert(ThreadLocalStorage::get_thread_ptr_offset() != 0,
+         "Thread Pointer Offset has not been initialized");
+  movl(thread, Address(thread, ThreadLocalStorage::get_thread_ptr_offset()));
+}
+
+bool MacroAssembler::needs_explicit_null_check(int offset) {
+  return offset < 0 || (int)os::vm_page_size() <= offset;
+}