// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <chrono>
#include <thread>
#ifdef _MSC_VER
#include <intrin.h>
#else
#include <x86intrin.h>
#endif
#include "common/x64/native_clock.h"
namespace Common {
#ifdef _MSC_VER
namespace {
struct uint128 {
u64 low;
u64 high;
};
u64 umuldiv64(u64 a, u64 b, u64 d) {
uint128 r{};
r.low = _umul128(a, b, &r.high);
u64 remainder;
return _udiv128(r.high, r.low, d, &remainder);
}
} // namespace
#else
namespace {
u64 umuldiv64(u64 a, u64 b, u64 d) {
const u64 diva = a / d;
const u64 moda = a % d;
const u64 divb = b / d;
const u64 modb = b % d;
return diva * b + moda * divb + moda * modb / d;
}
} // namespace
#endif
u64 EstimateRDTSCFrequency() {
const auto milli_10 = std::chrono::milliseconds{10};
// get current time
_mm_mfence();
const u64 tscStart = __rdtsc();
const auto startTime = std::chrono::high_resolution_clock::now();
// wait roughly 3 seconds
while (true) {
auto milli = std::chrono::duration_cast<std::chrono::milliseconds>(
std::chrono::high_resolution_clock::now() - startTime);
if (milli.count() >= 3000)
break;
std::this_thread::sleep_for(milli_10);
}
const auto endTime = std::chrono::high_resolution_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 = umuldiv64(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();
last_measure = __rdtsc();
accumulated_ticks = 0U;
}
u64 NativeClock::GetRTSC() {
rtsc_serialize.lock();
_mm_mfence();
const u64 current_measure = __rdtsc();
u64 diff = current_measure - last_measure;
diff = diff & ~static_cast<u64>(static_cast<s64>(diff) >> 63); // max(diff, 0)
if (current_measure > last_measure) {
last_measure = current_measure;
}
accumulated_ticks += diff;
rtsc_serialize.unlock();
return accumulated_ticks;
}
std::chrono::nanoseconds NativeClock::GetTimeNS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::nanoseconds{umuldiv64(rtsc_value, 1000000000, rtsc_frequency)};
}
std::chrono::microseconds NativeClock::GetTimeUS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::microseconds{umuldiv64(rtsc_value, 1000000, rtsc_frequency)};
}
std::chrono::milliseconds NativeClock::GetTimeMS() {
const u64 rtsc_value = GetRTSC();
return std::chrono::milliseconds{umuldiv64(rtsc_value, 1000, rtsc_frequency)};
}
u64 NativeClock::GetClockCycles() {
const u64 rtsc_value = GetRTSC();
return umuldiv64(rtsc_value, emulated_clock_frequency, rtsc_frequency);
}
u64 NativeClock::GetCPUCycles() {
const u64 rtsc_value = GetRTSC();
return umuldiv64(rtsc_value, emulated_cpu_frequency, rtsc_frequency);
}
} // namespace X64
} // namespace Common
