foreman
97 baris
1.9 KiB
C++
97 baris
1.9 KiB
C++
//
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// Copyright (c) 2008,2010 Advanced Micro Devices, Inc. All rights reserved.
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//
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#include "thread/semaphore.hpp"
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#include "thread/atomic.hpp"
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#include "thread/thread.hpp"
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#if defined(_WIN32) || defined(__CYGWIN__)
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# include <windows.h>
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#else // !_WIN32
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# include <semaphore.h>
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# include <errno.h>
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#endif // !_WIN32
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namespace amd {
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Semaphore::Semaphore()
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: state_(0)
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{
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#ifdef _WIN32
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handle_ = static_cast<void*>(CreateSemaphore(NULL, 0, LONG_MAX, NULL));
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assert(handle_ != NULL && "CreateSemaphore failed");
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#else // !_WIN32
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if (sem_init(&sem_, 0, 0) != 0) {
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fatal("sem_init() failed");
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}
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#endif // !_WIN32
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}
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Semaphore::~Semaphore()
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{
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#ifdef _WIN32
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if (!CloseHandle(static_cast<HANDLE>(handle_))) {
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fatal("CloseHandle() failed");
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}
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#else // !_WIN32
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if (sem_destroy(&sem_) != 0) {
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fatal("sem_destroy() failed");
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}
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#endif // !WIN32
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}
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void
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Semaphore::post()
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{
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int state;
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while (true) {
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state = state_;
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if (state > 0) {
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// Do a load acquire.
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MemoryOrder::fence();
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if (state == state_) {
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return;
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}
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continue;
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}
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if (state_.compareAndSet(state, state+1)) {
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break;
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}
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}
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if (state < 0) {
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// We have threads waiting on this event.
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#ifdef _WIN32
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ReleaseSemaphore(static_cast<HANDLE>(handle_), 1, NULL);
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#else // !_WIN32
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if (0 != sem_post(&sem_)) {
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fatal("sem_post() failed");
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}
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#endif // !_WIN32
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}
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}
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void
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Semaphore::wait()
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{
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if (state_-- > 0) {
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return;
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}
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#ifdef _WIN32
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if (WAIT_OBJECT_0 != WaitForSingleObject(
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static_cast<HANDLE>(handle_), INFINITE)) {
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fatal("WaitForSingleObject failed");
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}
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#else // !_WIN32
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while (0 != sem_wait(&sem_)) {
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if (EINTR != errno) {
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fatal("sem_wait() failed");
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}
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}
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#endif // !_WIN32
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}
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} // namespace amd
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