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// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <windows.h>
#include "common/windows/timer_resolution.h"
extern "C" {
// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtQueryTimerResolution.html
NTSYSAPI LONG NTAPI NtQueryTimerResolution(PULONG MinimumResolution, PULONG MaximumResolution,
PULONG CurrentResolution);
// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FTime%2FNtSetTimerResolution.html
NTSYSAPI LONG NTAPI NtSetTimerResolution(ULONG DesiredResolution, BOOLEAN SetResolution,
PULONG CurrentResolution);
// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FThread%2FNtDelayExecution.html
NTSYSAPI LONG NTAPI NtDelayExecution(BOOLEAN Alertable, PLARGE_INTEGER DelayInterval);
}
namespace Common::Windows {
namespace {
using namespace std::chrono;
constexpr nanoseconds ToNS(ULONG hundred_ns) {
return nanoseconds{hundred_ns * 100};
}
constexpr ULONG ToHundredNS(nanoseconds ns) {
return static_cast<ULONG>(ns.count()) / 100;
}
struct TimerResolution {
std::chrono::nanoseconds minimum;
std::chrono::nanoseconds maximum;
std::chrono::nanoseconds current;
};
TimerResolution GetTimerResolution() {
ULONG MinimumTimerResolution;
ULONG MaximumTimerResolution;
ULONG CurrentTimerResolution;
NtQueryTimerResolution(&MinimumTimerResolution, &MaximumTimerResolution,
&CurrentTimerResolution);
return {
.minimum{ToNS(MinimumTimerResolution)},
.maximum{ToNS(MaximumTimerResolution)},
.current{ToNS(CurrentTimerResolution)},
};
}
} // Anonymous namespace
nanoseconds GetMinimumTimerResolution() {
return GetTimerResolution().minimum;
}
nanoseconds GetMaximumTimerResolution() {
return GetTimerResolution().maximum;
}
nanoseconds GetCurrentTimerResolution() {
return GetTimerResolution().current;
}
nanoseconds SetCurrentTimerResolution(nanoseconds timer_resolution) {
// Set the timer resolution, and return the current timer resolution.
const auto DesiredTimerResolution = ToHundredNS(timer_resolution);
ULONG CurrentTimerResolution;
NtSetTimerResolution(DesiredTimerResolution, TRUE, &CurrentTimerResolution);
return ToNS(CurrentTimerResolution);
}
nanoseconds SetCurrentTimerResolutionToMaximum() {
return SetCurrentTimerResolution(GetMaximumTimerResolution());
}
void SleepForOneTick() {
LARGE_INTEGER DelayInterval{
.QuadPart{-1},
};
NtDelayExecution(FALSE, &DelayInterval);
}
} // namespace Common::Windows
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