// 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() {
const auto milli_10 = std::chrono::milliseconds{10};
// get current time
_mm_mfence();
const u64 tscStart = __rdtsc();
const auto startTime = std::chrono::steady_clock::now();
// wait roughly 3 seconds
while (true) {
auto milli = std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::steady_clock::now() - startTime);
if (milli.count() >= 3000)
break;
std::this_thread::sleep_for(milli_10);
}
const auto endTime = std::chrono::steady_clock::now();
_mm_mfence();
const u64 tscEnd = __rdtsc();
// calculate difference
const u64 timer_diff =
std::chrono::duration_cast<std::chrono::nanoseconds>(endTime - startTime).count();
const u64 tsc_diff = tscEnd - tscStart;
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
