Merge pull request #5964 from bunnei/timing-fix
common: wall_clock: Fix integer overflow with StandardWallClock.
This commit is contained in:
commit
def03d4075
|
@ -98,4 +98,24 @@ namespace Common {
|
|||
#endif
|
||||
}
|
||||
|
||||
// This function divides a u128 by a u32 value and produces two u64 values:
|
||||
// the result of division and the remainder
|
||||
[[nodiscard]] static inline std::pair<u64, u64> Divide128On32(u128 dividend, u32 divisor) {
|
||||
u64 remainder = dividend[0] % divisor;
|
||||
u64 accum = dividend[0] / divisor;
|
||||
if (dividend[1] == 0)
|
||||
return {accum, remainder};
|
||||
// We ignore dividend[1] / divisor as that overflows
|
||||
const u64 first_segment = (dividend[1] % divisor) << 32;
|
||||
accum += (first_segment / divisor) << 32;
|
||||
const u64 second_segment = (first_segment % divisor) << 32;
|
||||
accum += (second_segment / divisor);
|
||||
remainder += second_segment % divisor;
|
||||
if (remainder >= divisor) {
|
||||
accum++;
|
||||
remainder -= divisor;
|
||||
}
|
||||
return {accum, remainder};
|
||||
}
|
||||
|
||||
} // namespace Common
|
||||
|
|
|
@ -20,9 +20,7 @@ using base_time_point = std::chrono::time_point<base_timer>;
|
|||
class StandardWallClock final : public WallClock {
|
||||
public:
|
||||
explicit StandardWallClock(u64 emulated_cpu_frequency_, u64 emulated_clock_frequency_)
|
||||
: WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, false),
|
||||
emulated_clock_factor{GetFixedPoint64Factor(emulated_clock_frequency, 1000000000)},
|
||||
emulated_cpu_factor{GetFixedPoint64Factor(emulated_cpu_frequency, 1000000000)} {
|
||||
: WallClock(emulated_cpu_frequency_, emulated_clock_frequency_, false) {
|
||||
start_time = base_timer::now();
|
||||
}
|
||||
|
||||
|
@ -45,11 +43,16 @@ public:
|
|||
}
|
||||
|
||||
u64 GetClockCycles() override {
|
||||
return MultiplyHigh(GetTimeNS().count(), emulated_clock_factor);
|
||||
std::chrono::nanoseconds time_now = GetTimeNS();
|
||||
const u128 temporary =
|
||||
Common::Multiply64Into128(time_now.count(), emulated_clock_frequency);
|
||||
return Common::Divide128On32(temporary, 1000000000).first;
|
||||
}
|
||||
|
||||
u64 GetCPUCycles() override {
|
||||
return MultiplyHigh(GetTimeNS().count(), emulated_cpu_factor);
|
||||
std::chrono::nanoseconds time_now = GetTimeNS();
|
||||
const u128 temporary = Common::Multiply64Into128(time_now.count(), emulated_cpu_frequency);
|
||||
return Common::Divide128On32(temporary, 1000000000).first;
|
||||
}
|
||||
|
||||
void Pause([[maybe_unused]] bool is_paused) override {
|
||||
|
@ -58,8 +61,6 @@ public:
|
|||
|
||||
private:
|
||||
base_time_point start_time;
|
||||
const u64 emulated_clock_factor;
|
||||
const u64 emulated_cpu_factor;
|
||||
};
|
||||
|
||||
#ifdef ARCHITECTURE_x86_64
|
||||
|
|
Reference in New Issue