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-rw-r--r--src/core/hle/kernel/semaphore.cpp94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/core/hle/kernel/semaphore.cpp b/src/core/hle/kernel/semaphore.cpp
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+++ b/src/core/hle/kernel/semaphore.cpp
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+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <queue>
+
+#include "common/common.h"
+
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/semaphore.h"
+#include "core/hle/kernel/thread.h"
+
+namespace Kernel {
+
+class Semaphore : public Object {
+public:
+ std::string GetTypeName() const override { return "Semaphore"; }
+ std::string GetName() const override { return name; }
+
+ static Kernel::HandleType GetStaticHandleType() { return Kernel::HandleType::Semaphore; }
+ Kernel::HandleType GetHandleType() const override { return Kernel::HandleType::Semaphore; }
+
+ u32 max_count; ///< Maximum number of simultaneous holders the semaphore can have
+ u32 available_count; ///< Number of free slots left in the semaphore
+ std::queue<Handle> waiting_threads; ///< Threads that are waiting for the semaphore
+ std::string name; ///< Name of semaphore (optional)
+
+ /**
+ * Tests whether a semaphore still has free slots
+ * @return Whether the semaphore is available
+ */
+ bool IsAvailable() const {
+ return available_count > 0;
+ }
+
+ ResultVal<bool> WaitSynchronization() override {
+ bool wait = !IsAvailable();
+
+ if (wait) {
+ Kernel::WaitCurrentThread(WAITTYPE_SEMA, GetHandle());
+ waiting_threads.push(GetCurrentThreadHandle());
+ } else {
+ --available_count;
+ }
+
+ return MakeResult<bool>(wait);
+ }
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ResultCode CreateSemaphore(Handle* handle, u32 initial_count,
+ u32 max_count, const std::string& name) {
+
+ if (initial_count > max_count)
+ return ResultCode(ErrorDescription::InvalidCombination, ErrorModule::Kernel,
+ ErrorSummary::WrongArgument, ErrorLevel::Permanent);
+
+ Semaphore* semaphore = new Semaphore;
+ *handle = g_object_pool.Create(semaphore);
+
+ // When the semaphore is created, some slots are reserved for other threads,
+ // and the rest is reserved for the caller thread
+ semaphore->max_count = max_count;
+ semaphore->available_count = initial_count;
+ semaphore->name = name;
+
+ return RESULT_SUCCESS;
+}
+
+ResultCode ReleaseSemaphore(s32* count, Handle handle, s32 release_count) {
+ Semaphore* semaphore = g_object_pool.Get<Semaphore>(handle);
+ if (semaphore == nullptr)
+ return InvalidHandle(ErrorModule::Kernel);
+
+ if (semaphore->max_count - semaphore->available_count < release_count)
+ return ResultCode(ErrorDescription::OutOfRange, ErrorModule::Kernel,
+ ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
+
+ *count = semaphore->available_count;
+ semaphore->available_count += release_count;
+
+ // Notify some of the threads that the semaphore has been released
+ // stop once the semaphore is full again or there are no more waiting threads
+ while (!semaphore->waiting_threads.empty() && semaphore->IsAvailable()) {
+ Kernel::ResumeThreadFromWait(semaphore->waiting_threads.front());
+ semaphore->waiting_threads.pop();
+ --semaphore->available_count;
+ }
+
+ return RESULT_SUCCESS;
+}
+
+} // namespace