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