The Tor Browser: gfx/skia/trunk/src/ports/SkAtomics

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /*

     2  * Copyright 2013 Google Inc.

     3  *

     4  * Use of this source code is governed by a BSD-style license that can be

     5  * found in the LICENSE file.

     6  */

     8 #ifndef SkAtomics_win_DEFINED

     9 #define SkAtomics_win_DEFINED

    11 /** Windows Interlocked atomics. */

    13 #include <intrin.h>

    14 #include <stdint.h>

    16 //MSDN says in order to declare an interlocked function for use as an

    17 //intrinsic, include intrin.h and put the function in a #pragma intrinsic

    18 //directive.

    19 //The pragma appears to be unnecessary, but doesn't hurt.

    20 #pragma intrinsic(_InterlockedIncrement, _InterlockedExchangeAdd, _InterlockedDecrement)

    21 #pragma intrinsic(_InterlockedCompareExchange)

    23 static inline int32_t sk_atomic_inc(int32_t* addr) {

    24     // InterlockedIncrement returns the new value, we want to return the old.

    25     return _InterlockedIncrement(reinterpret_cast<long*>(addr)) - 1;

    26 }

    28 static inline int32_t sk_atomic_add(int32_t* addr, int32_t inc) {

    29     return _InterlockedExchangeAdd(reinterpret_cast<long*>(addr), static_cast<long>(inc));

    30 }

    32 static inline int32_t sk_atomic_dec(int32_t* addr) {

    33     // InterlockedDecrement returns the new value, we want to return the old.

    34     return _InterlockedDecrement(reinterpret_cast<long*>(addr)) + 1;

    35 }

    37 static inline void sk_membar_acquire__after_atomic_dec() { }

    39 static inline int32_t sk_atomic_conditional_inc(int32_t* addr) {

    40     long value = *addr;

    41     while (true) {

    42         if (value == 0) {

    43             return 0;

    44         }

    46         long before = _InterlockedCompareExchange(reinterpret_cast<long*>(addr), value + 1, value);

    48         if (before == value) {

    49             return value;

    50         } else {

    51             value = before;

    52         }

    53     }

    54 }

    56 static inline bool sk_atomic_cas(int32_t* addr, int32_t before, int32_t after) {

    57     return _InterlockedCompareExchange(reinterpret_cast<long*>(addr), after, before) == before;

    58 }

    60 static inline void sk_membar_acquire__after_atomic_conditional_inc() { }

    62 #endif

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