67 lines
1.6 KiB
C++
67 lines
1.6 KiB
C++
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// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#include <thread>
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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#include "common/x64/cpu_detect.h"
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#include "common/x64/cpu_wait.h"
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namespace Common::X64 {
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#ifdef _MSC_VER
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__forceinline static u64 FencedRDTSC() {
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_mm_lfence();
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_ReadWriteBarrier();
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const u64 result = __rdtsc();
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_mm_lfence();
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_ReadWriteBarrier();
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return result;
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}
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__forceinline static void TPAUSE() {
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// 100,000 cycles is a reasonable amount of time to wait to save on CPU resources.
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// For reference:
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// At 1 GHz, 100K cycles is 100us
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// At 2 GHz, 100K cycles is 50us
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// At 4 GHz, 100K cycles is 25us
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static constexpr auto PauseCycles = 100'000;
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_tpause(0, FencedRDTSC() + PauseCycles);
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}
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#else
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static u64 FencedRDTSC() {
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u64 eax;
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u64 edx;
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asm volatile("lfence\n\t"
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"rdtsc\n\t"
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"lfence\n\t"
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: "=a"(eax), "=d"(edx));
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return (edx << 32) | eax;
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}
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static void TPAUSE() {
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// 100,000 cycles is a reasonable amount of time to wait to save on CPU resources.
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// For reference:
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// At 1 GHz, 100K cycles is 100us
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// At 2 GHz, 100K cycles is 50us
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// At 4 GHz, 100K cycles is 25us
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static constexpr auto PauseCycles = 100'000;
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asm volatile("tpause %%ecx" : : "c"(0), "d"((FencedRDTSC() + PauseCycles) >> 32));
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}
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#endif
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void MicroSleep() {
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static const bool has_waitpkg = GetCPUCaps().waitpkg;
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if (has_waitpkg) {
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TPAUSE();
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} else {
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std::this_thread::yield();
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}
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}
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} // namespace Common::X64
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