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// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#if defined(_WIN32)
#include <windows.h>
#else
#include <time.h>
#endif
#include "common/steady_clock.h"
namespace Common {
#ifdef _WIN32
static s64 WindowsQueryPerformanceFrequency() {
LARGE_INTEGER frequency;
QueryPerformanceFrequency(&frequency);
return frequency.QuadPart;
}
static s64 WindowsQueryPerformanceCounter() {
LARGE_INTEGER counter;
QueryPerformanceCounter(&counter);
return counter.QuadPart;
}
#endif
SteadyClock::time_point SteadyClock::Now() noexcept {
#if defined(_WIN32)
static const auto freq = WindowsQueryPerformanceFrequency();
const auto counter = WindowsQueryPerformanceCounter();
// 10 MHz is a very common QPC frequency on modern PCs.
// Optimizing for this specific frequency can double the performance of
// this function by avoiding the expensive frequency conversion path.
static constexpr s64 TenMHz = 10'000'000;
if (freq == TenMHz) [[likely]] {
static_assert(period::den % TenMHz == 0);
static constexpr s64 Multiplier = period::den / TenMHz;
return time_point{duration{counter * Multiplier}};
}
const auto whole = (counter / freq) * period::den;
const auto part = (counter % freq) * period::den / freq;
return time_point{duration{whole + part}};
#elif defined(__APPLE__)
return time_point{duration{clock_gettime_nsec_np(CLOCK_MONOTONIC_RAW)}};
#else
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return time_point{std::chrono::seconds{ts.tv_sec} + std::chrono::nanoseconds{ts.tv_nsec}};
#endif
}
}; // namespace Common
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