Common: Implement WallClock Interface and implement a native clock for x64

src/common/x64/native_clock.h

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+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <optional>
+
+#include "common/spin_lock.h"
+#include "common/wall_clock.h"
+
+namespace Common {
+
+namespace X64 {
+class NativeClock : public WallClock {
+public:
+    NativeClock(u64 emulated_cpu_frequency, u64 emulated_clock_frequency, u64 rtsc_frequency);
+
+    std::chrono::nanoseconds GetTimeNS() override;
+
+    std::chrono::microseconds GetTimeUS() override;
+
+    std::chrono::milliseconds GetTimeMS() override;
+
+    u64 GetClockCycles() override;
+
+    u64 GetCPUCycles() override;
+
+private:
+    u64 GetRTSC();
+
+    SpinLock rtsc_serialize{};
+    u64 last_measure{};
+    u64 accumulated_ticks{};
+    u64 rtsc_frequency;
+};
+} // namespace X64
+
+u64 EstimateRDTSCFrequency();
+
+} // namespace Common