common: add arm64 native clock

src/common/arm64/native_clock.cpp

@@ -0,0 +1,72 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "common/arm64/native_clock.h"
+
+namespace Common::Arm64 {
+
+namespace {
+
+NativeClock::FactorType GetFixedPointFactor(u64 num, u64 den) {
+    return (static_cast<NativeClock::FactorType>(num) << 64) / den;
+}
+
+u64 MultiplyHigh(u64 m, NativeClock::FactorType factor) {
+    return static_cast<u64>((m * factor) >> 64);
+}
+
+} // namespace
+
+NativeClock::NativeClock() {
+    const u64 host_cntfrq = GetHostCNTFRQ();
+    ns_cntfrq_factor = GetFixedPointFactor(NsRatio::den, host_cntfrq);
+    us_cntfrq_factor = GetFixedPointFactor(UsRatio::den, host_cntfrq);
+    ms_cntfrq_factor = GetFixedPointFactor(MsRatio::den, host_cntfrq);
+    guest_cntfrq_factor = GetFixedPointFactor(CNTFRQ, host_cntfrq);
+    gputick_cntfrq_factor = GetFixedPointFactor(GPUTickFreq, host_cntfrq);
+}
+
+std::chrono::nanoseconds NativeClock::GetTimeNS() const {
+    return std::chrono::nanoseconds{MultiplyHigh(GetHostTicksElapsed(), ns_cntfrq_factor)};
+}
+
+std::chrono::microseconds NativeClock::GetTimeUS() const {
+    return std::chrono::microseconds{MultiplyHigh(GetHostTicksElapsed(), us_cntfrq_factor)};
+}
+
+std::chrono::milliseconds NativeClock::GetTimeMS() const {
+    return std::chrono::milliseconds{MultiplyHigh(GetHostTicksElapsed(), ms_cntfrq_factor)};
+}
+
+u64 NativeClock::GetCNTPCT() const {
+    return MultiplyHigh(GetHostTicksElapsed(), guest_cntfrq_factor);
+}
+
+u64 NativeClock::GetGPUTick() const {
+    return MultiplyHigh(GetHostTicksElapsed(), gputick_cntfrq_factor);
+}
+
+u64 NativeClock::GetHostTicksNow() const {
+    u64 cntvct_el0 = 0;
+    asm volatile("dsb ish\n\t"
+                 "mrs %[cntvct_el0], cntvct_el0\n\t"
+                 "dsb ish\n\t"
+                 : [cntvct_el0] "=r"(cntvct_el0));
+    return cntvct_el0;
+}
+
+u64 NativeClock::GetHostTicksElapsed() const {
+    return GetHostTicksNow();
+}
+
+bool NativeClock::IsNative() const {
+    return true;
+}
+
+u64 NativeClock::GetHostCNTFRQ() {
+    u64 cntfrq_el0 = 0;
+    asm("mrs %[cntfrq_el0], cntfrq_el0" : [cntfrq_el0] "=r"(cntfrq_el0));
+    return cntfrq_el0;
+}
+
+} // namespace Common::Arm64