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// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <array>
#include <chrono>
#include <limits>
#include <mutex>
#include <thread>
#include "common/atomic_ops.h"
#include "common/uint128.h"
#include "common/x64/native_clock.h"
namespace Common {
u64 EstimateRDTSCFrequency() {
// Discard the first result measuring the rdtsc.
_mm_mfence();
__rdtsc();
std::this_thread::sleep_for(std::chrono::milliseconds{1});
_mm_mfence();
__rdtsc();
// Get the current time.
const auto start_time = std::chrono::steady_clock::now();
_mm_mfence();
const u64 tsc_start = __rdtsc();
// Wait for 200 milliseconds.
std::this_thread::sleep_for(std::chrono::milliseconds{200});
const auto end_time = std::chrono::steady_clock::now();
_mm_mfence();
const u64 tsc_end = __rdtsc();
// Calculate differences.
const u64 timer_diff = static_cast<u64>(
std::chrono::duration_cast<std::chrono::nanoseconds>(end_time - start_time).count());
const u64 tsc_diff = tsc_end - tsc_start;
const u64 tsc_freq = MultiplyAndDivide64(tsc_diff, 1000000000ULL, timer_diff);
return tsc_freq;
}
namespace X64 {
NativeClock::NativeClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequency_,
u64 rtsc_frequency_)
: WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, true), rtsc_frequency{
rtsc_frequency_} {
_mm_mfence();
time_point.inner.last_measure = __rdtsc();
time_point.inner.accumulated_ticks = 0U;
ns_rtsc_factor = GetFixedPoint64Factor(1000000000, rtsc_frequency);
us_rtsc_factor = GetFixedPoint64Factor(1000000, rtsc_frequency);
ms_rtsc_factor = GetFixedPoint64Factor(1000, rtsc_frequency);
clock_rtsc_factor = GetFixedPoint64Factor(emulated_clock_frequency, rtsc_frequency);
cpu_rtsc_factor = GetFixedPoint64Factor(emulated_cpu_frequency, rtsc_frequency);
}
u64 NativeClock::GetRTSC() {
TimePoint new_time_point{};
TimePoint current_time_point{};
do {
current_time_point.pack = time_point.pack;
_mm_mfence();
const u64 current_measure = __rdtsc();
u64 diff = current_measure - current_time_point.inner.last_measure;
diff = diff & ~static_cast<u64>(static_cast<s64>(diff) >> 63); // max(diff, 0)
new_time_point.inner.last_measure = current_measure > current_time_point.inner.last_measure
? current_measure
: current_time_point.inner.last_measure;
new_time_point.inner.accumulated_ticks = current_time_point.inner.accumulated_ticks + diff;
} while (!Common::AtomicCompareAndSwap(time_point.pack.data(), new_time_point.pack,
current_time_point.pack));
/// The clock cannot be more precise than the guest timer, remove the lower bits
return new_time_point.inner.accumulated_ticks & inaccuracy_mask;
}
void NativeClock::Pause(bool is_paused) {
if (!is_paused) {
TimePoint current_time_point{};
TimePoint new_time_point{};
do {
current_time_point.pack = time_point.pack;
new_time_point.pack = current_time_point.pack;
_mm_mfence();
new_time_point.inner.last_measure = __rdtsc();
} while (!Common::AtomicCompareAndSwap(time_point.pack.data(), new_time_point.pack,
current_time_point.pack));
}
}
std::chrono::nanoseconds NativeClock::GetTimeNS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::nanoseconds{MultiplyHigh(rtsc_value, ns_rtsc_factor)};
}
std::chrono::microseconds NativeClock::GetTimeUS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::microseconds{MultiplyHigh(rtsc_value, us_rtsc_factor)};
}
std::chrono::milliseconds NativeClock::GetTimeMS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::milliseconds{MultiplyHigh(rtsc_value, ms_rtsc_factor)};
}
u64 NativeClock::GetClockCycles() {
const u64 rtsc_value = GetRTSC();
return MultiplyHigh(rtsc_value, clock_rtsc_factor);
}
u64 NativeClock::GetCPUCycles() {
const u64 rtsc_value = GetRTSC();
return MultiplyHigh(rtsc_value, cpu_rtsc_factor);
}
} // namespace X64
} // namespace Common
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