1 files changed, 57 insertions, 0 deletions
diff --git a/src/core/hle/kernel/k_light_condition_variable.h b/src/core/hle/kernel/k_light_condition_variable.h
new file mode 100644
index 000000000..362d0db28
--- /dev/null
+++ b/src/core/hle/kernel/k_light_condition_variable.h
@@ -0,0 +1,57 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+// This file references various implementation details from Atmosphere, an open-source firmware for
+// the Nintendo Switch. Copyright 2018-2020 Atmosphere-NX.
+
+#pragma once
+
+#include "common/common_types.h"
+#include "core/hle/kernel/k_scheduler.h"
+#include "core/hle/kernel/k_scoped_scheduler_lock_and_sleep.h"
+#include "core/hle/kernel/k_thread_queue.h"
+#include "core/hle/kernel/time_manager.h"
+
+namespace Kernel {
+class KernelCore;
+
+class KLightConditionVariable {
+public:
+    explicit KLightConditionVariable(KernelCore& kernel) : thread_queue(kernel), kernel(kernel) {}
+
+    void Wait(KLightLock* lock, s64 timeout = -1) {
+        WaitImpl(lock, timeout);
+        lock->Lock();
+    }
+
+    void Broadcast() {
+        KScopedSchedulerLock lk{kernel};
+        while (thread_queue.WakeupFrontThread() != nullptr) {
+            // We want to signal all threads, and so should continue waking up until there's nothing
+            // to wake.
+        }
+    }
+
+private:
+    void WaitImpl(KLightLock* lock, s64 timeout) {
+        KThread* owner = GetCurrentThreadPointer(kernel);
+
+        // Sleep the thread.
+        {
+            KScopedSchedulerLockAndSleep lk(kernel, owner, timeout);
+            lock->Unlock();
+
+            if (!thread_queue.SleepThread(owner)) {
+                lk.CancelSleep();
+                return;
+            }
+        }
+
+        // Cancel the task that the sleep setup.
+        kernel.TimeManager().UnscheduleTimeEvent(owner);
+    }
+    KThreadQueue thread_queue;
+    KernelCore& kernel;
+};
+} // namespace Kernel