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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkAtomics_win_DEFINED
#define SkAtomics_win_DEFINED
/** Windows Interlocked atomics. */
#include <intrin.h>
#include <stdint.h>
//MSDN says in order to declare an interlocked function for use as an
//intrinsic, include intrin.h and put the function in a #pragma intrinsic
//directive.
//The pragma appears to be unnecessary, but doesn't hurt.
#pragma intrinsic(_InterlockedIncrement, _InterlockedExchangeAdd, _InterlockedDecrement)
#pragma intrinsic(_InterlockedCompareExchange)
static inline int32_t sk_atomic_inc(int32_t* addr) {
// InterlockedIncrement returns the new value, we want to return the old.
return _InterlockedIncrement(reinterpret_cast<long*>(addr)) - 1;
}
static inline int32_t sk_atomic_add(int32_t* addr, int32_t inc) {
return _InterlockedExchangeAdd(reinterpret_cast<long*>(addr), static_cast<long>(inc));
}
static inline int32_t sk_atomic_dec(int32_t* addr) {
// InterlockedDecrement returns the new value, we want to return the old.
return _InterlockedDecrement(reinterpret_cast<long*>(addr)) + 1;
}
static inline void sk_membar_acquire__after_atomic_dec() { }
static inline int32_t sk_atomic_conditional_inc(int32_t* addr) {
long value = *addr;
while (true) {
if (value == 0) {
return 0;
}
long before = _InterlockedCompareExchange(reinterpret_cast<long*>(addr), value + 1, value);
if (before == value) {
return value;
} else {
value = before;
}
}
}
static inline bool sk_atomic_cas(int32_t* addr, int32_t before, int32_t after) {
return _InterlockedCompareExchange(reinterpret_cast<long*>(addr), after, before) == before;
}
static inline void sk_membar_acquire__after_atomic_conditional_inc() { }
#endif
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