1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "base/quasi_atomic.h" 18 19 #include "base/mutex.h" 20 #include "base/stl_util.h" 21 #include "thread-current-inl.h" 22 23 namespace art { 24 25 std::vector<Mutex*>* QuasiAtomic::gSwapMutexes = nullptr; 26 27 Mutex* QuasiAtomic::GetSwapMutex(const volatile int64_t* addr) { 28 return (*gSwapMutexes)[(reinterpret_cast<uintptr_t>(addr) >> 3U) % kSwapMutexCount]; 29 } 30 31 void QuasiAtomic::Startup() { 32 if (NeedSwapMutexes(kRuntimeISA)) { 33 gSwapMutexes = new std::vector<Mutex*>; 34 for (size_t i = 0; i < kSwapMutexCount; ++i) { 35 gSwapMutexes->push_back(new Mutex("QuasiAtomic stripe", kSwapMutexesLock)); 36 } 37 } 38 } 39 40 void QuasiAtomic::Shutdown() { 41 if (NeedSwapMutexes(kRuntimeISA)) { 42 STLDeleteElements(gSwapMutexes); 43 delete gSwapMutexes; 44 } 45 } 46 47 int64_t QuasiAtomic::SwapMutexRead64(volatile const int64_t* addr) { 48 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 49 return *addr; 50 } 51 52 void QuasiAtomic::SwapMutexWrite64(volatile int64_t* addr, int64_t value) { 53 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 54 *addr = value; 55 } 56 57 58 bool QuasiAtomic::SwapMutexCas64(int64_t old_value, int64_t new_value, volatile int64_t* addr) { 59 MutexLock mu(Thread::Current(), *GetSwapMutex(addr)); 60 if (*addr == old_value) { 61 *addr = new_value; 62 return true; 63 } 64 return false; 65 } 66 67 } // namespace art 68
