/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "base/quasi_atomic.h"
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#include "base/mutex.h"
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#include "base/stl_util.h"
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#include "thread-current-inl.h"
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namespace art {
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std::vector<Mutex*>* QuasiAtomic::gSwapMutexes = nullptr;
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Mutex* QuasiAtomic::GetSwapMutex(const volatile int64_t* addr) {
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return (*gSwapMutexes)[(reinterpret_cast<uintptr_t>(addr) >> 3U) % kSwapMutexCount];
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}
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void QuasiAtomic::Startup() {
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if (NeedSwapMutexes(kRuntimeISA)) {
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gSwapMutexes = new std::vector<Mutex*>;
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for (size_t i = 0; i < kSwapMutexCount; ++i) {
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gSwapMutexes->push_back(new Mutex("QuasiAtomic stripe", kSwapMutexesLock));
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}
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}
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}
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void QuasiAtomic::Shutdown() {
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if (NeedSwapMutexes(kRuntimeISA)) {
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STLDeleteElements(gSwapMutexes);
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delete gSwapMutexes;
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}
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}
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int64_t QuasiAtomic::SwapMutexRead64(volatile const int64_t* addr) {
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MutexLock mu(Thread::Current(), *GetSwapMutex(addr));
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return *addr;
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}
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void QuasiAtomic::SwapMutexWrite64(volatile int64_t* addr, int64_t value) {
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MutexLock mu(Thread::Current(), *GetSwapMutex(addr));
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*addr = value;
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}
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bool QuasiAtomic::SwapMutexCas64(int64_t old_value, int64_t new_value, volatile int64_t* addr) {
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MutexLock mu(Thread::Current(), *GetSwapMutex(addr));
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if (*addr == old_value) {
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*addr = new_value;
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return true;
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}
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return false;
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}
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} // namespace art
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