/* * Copyright (C) 2007, 2008, 2010, 2012 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. * 3. Neither the name of Apple Inc. ("Apple") nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY APPLE 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 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. * * * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license * is virtually identical to the Apple license above but is included here for completeness. * * Boost Software License - Version 1.0 - August 17th, 2003 * * Permission is hereby granted, free of charge, to any person or organization * obtaining a copy of the software and accompanying documentation covered by * this license (the "Software") to use, reproduce, display, distribute, * execute, and transmit the Software, and to prepare derivative works of the * Software, and to permit third-parties to whom the Software is furnished to * do so, all subject to the following: * * The copyright notices in the Software and this entire statement, including * the above license grant, this restriction and the following disclaimer, * must be included in all copies of the Software, in whole or in part, and * all derivative works of the Software, unless such copies or derivative * works are solely in the form of machine-executable object code generated by * a source language processor. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ #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) && !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