1 files changed, 72 insertions, 0 deletions

diff --git a/src/common/atomic_win32.h b/src/common/atomic_win32.h
new file mode 100644
index 000000000..760b16d4d
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+++ b/src/common/atomic_win32.h
@@ -0,0 +1,72 @@
+// Copyright 2013 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#ifndef _ATOMIC_WIN32_H_
+#define _ATOMIC_WIN32_H_
+
+#include "common.h"
+#include <intrin.h>
+#include <Windows.h>
+
+// Atomic operations are performed in a single step by the CPU. It is
+// impossible for other threads to see the operation "half-done."
+//
+// Some atomic operations can be combined with different types of memory
+// barriers called "Acquire semantics" and "Release semantics", defined below.
+//
+// Acquire semantics: Future memory accesses cannot be relocated to before the
+//                    operation.
+//
+// Release semantics: Past memory accesses cannot be relocated to after the
+//                    operation.
+//
+// These barriers affect not only the compiler, but also the CPU.
+//
+// NOTE: Acquire and Release are not differentiated right now. They perform a
+// full memory barrier instead of a "one-way" memory barrier. The newest
+// Windows SDK has Acquire and Release versions of some Interlocked* functions.
+
+namespace Common
+{
+
+inline void AtomicAdd(volatile u32& target, u32 value) {
+    InterlockedExchangeAdd((volatile LONG*)&target, (LONG)value);
+}
+
+inline void AtomicAnd(volatile u32& target, u32 value) {
+    _InterlockedAnd((volatile LONG*)&target, (LONG)value);
+}
+
+inline void AtomicIncrement(volatile u32& target) {
+    InterlockedIncrement((volatile LONG*)&target);
+}
+
+inline void AtomicDecrement(volatile u32& target) {
+    InterlockedDecrement((volatile LONG*)&target);
+}
+
+inline u32 AtomicLoad(volatile u32& src) {
+    return src; // 32-bit reads are always atomic.
+}
+inline u32 AtomicLoadAcquire(volatile u32& src) {
+    u32 result = src; // 32-bit reads are always atomic.
+    _ReadBarrier(); // Compiler instruction only. x86 loads always have acquire semantics.
+    return result;
+}
+
+inline void AtomicOr(volatile u32& target, u32 value) {
+    _InterlockedOr((volatile LONG*)&target, (LONG)value);
+}
+
+inline void AtomicStore(volatile u32& dest, u32 value) {
+    dest = value; // 32-bit writes are always atomic.
+}
+inline void AtomicStoreRelease(volatile u32& dest, u32 value) {
+    _WriteBarrier(); // Compiler instruction only. x86 stores always have release semantics.
+    dest = value; // 32-bit writes are always atomic.
+}
+
+}
+
+#endif