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
GetSwapMutex(const volatile int64_t * addr)27 Mutex* QuasiAtomic::GetSwapMutex(const volatile int64_t* addr) {
28 return (*gSwapMutexes)[(reinterpret_cast<uintptr_t>(addr) >> 3U) % kSwapMutexCount];
29 }
30
Startup()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
Shutdown()40 void QuasiAtomic::Shutdown() {
41 if (NeedSwapMutexes(kRuntimeISA)) {
42 STLDeleteElements(gSwapMutexes);
43 delete gSwapMutexes;
44 }
45 }
46
SwapMutexRead64(volatile const int64_t * addr)47 int64_t QuasiAtomic::SwapMutexRead64(volatile const int64_t* addr) {
48 MutexLock mu(Thread::Current(), *GetSwapMutex(addr));
49 return *addr;
50 }
51
SwapMutexWrite64(volatile int64_t * addr,int64_t value)52 void QuasiAtomic::SwapMutexWrite64(volatile int64_t* addr, int64_t value) {
53 MutexLock mu(Thread::Current(), *GetSwapMutex(addr));
54 *addr = value;
55 }
56
57
SwapMutexCas64(int64_t old_value,int64_t new_value,volatile int64_t * addr)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