| /* |
| * Copyright (C) 2007, 2008, 2010, 2012, 2015 Apple Inc. All rights reserved. |
| * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com) |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
| * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "Atomics.h" |
| |
| // Some architectures, like MIPS32, don't have GCC implementation for builtin __sync_* functions |
| // with 64 bits variable size. Official GCC answer for the problem: If a target doesn't support |
| // atomic operations on certain variable sizes, you are out of luck with atomicity in that case |
| // (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56296). GCC >= 4.8 will support __atomic_* builtin |
| // functions for this purpose for all the GCC targets, but for current compilers we have to include |
| // our own implementation. |
| #if COMPILER(GCC_OR_CLANG) && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8) && USE(PTHREADS) |
| |
| #include "ThreadingPrimitives.h" |
| |
| namespace WTF { |
| |
| static const size_t kSwapLockCount = 32; |
| static Mutex s_swapLocks[kSwapLockCount]; |
| |
| static inline Mutex& getSwapLock(const volatile int64_t* addr) |
| { |
| return s_swapLocks[(reinterpret_cast<intptr_t>(addr) >> 3U) % kSwapLockCount]; |
| } |
| |
| static int64_t atomicStep(int64_t volatile* addend, int64_t step) |
| { |
| Mutex& mutex = getSwapLock(addend); |
| |
| mutex.lock(); |
| int64_t value = *addend + step; |
| *addend = value; |
| mutex.unlock(); |
| |
| return value; |
| } |
| |
| extern "C" { |
| |
| int64_t __sync_add_and_fetch_8(int64_t volatile* addend, int64_t value) |
| { |
| return atomicStep(addend, value); |
| } |
| |
| int64_t __sync_sub_and_fetch_8(int64_t volatile* addend, int64_t value) |
| { |
| return atomicStep(addend, -value); |
| } |
| |
| } // extern "C" |
| |
| } // namespace WTF |
| |
| #endif |