- Add AtomicOperations::CompareAndSwapWord

runtime/vm/atomic_win.h

Index: runtime/vm/atomic_win.h
===================================================================
--- runtime/vm/atomic_win.h	(working copy)
+++ runtime/vm/atomic_win.h	(working copy)
@@ -2,15 +2,20 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#include "platform/globals.h"
-#if defined(TARGET_OS_WINDOWS)
+#ifndef VM_ATOMIC_WIN_H_
+#define VM_ATOMIC_WIN_H_
 
-#include "vm/atomic.h"
+#if !defined VM_ATOMIC_H_
+#error Do not include atomic_win.h directly. Use atomic.h instead.
+#endif
 
+#if !defined(TARGET_OS_WINDOWS)
+#error This file should only be included on Windows builds.
+#endif
+
 namespace dart {
 
-
-uintptr_t AtomicOperations::FetchAndIncrement(uintptr_t* p) {
+inline uintptr_t AtomicOperations::FetchAndIncrement(uintptr_t* p) {
 #if defined(TARGET_ARCH_X64)
   return static_cast<uintptr_t>(
       InterlockedIncrement64(reinterpret_cast<LONGLONG*>(p))) - 1;
@@ -23,6 +28,24 @@
 }
 
 
+inline uword AtomicOperations::CompareAndSwapWord(uword* ptr,
+                                                  uword old_value,
+                                                  uword new_value) {
+#if defined(TARGET_ARCH_X64)
+  return static_cast<uword>(
+      InterlockedCompareExchange64(reinterpret_cast<LONG*>(ptr),
+                                   static_cast<LONG>(new_value),
+                                   static_cast<LONG>(old_value)));
+#elif defined(TARGET_ARCH_IA32)
+  return static_cast<uword>(
+      InterlockedCompareExchange(reinterpret_cast<LONGLONG*>(ptr),
+                                 static_cast<LONGLONG>(new_value),
+                                 static_cast<LONGLONG>(old_value)));
+#else
+  UNIMPLEMENTED();
+#endif
+}
+
 }  // namespace dart
 
-#endif  // defined(TARGET_OS_WINDOWS)
+#endif  // VM_ATOMIC_WIN_H_