diff options
| -rw-r--r-- | src/common/uint128.h | 20 | ||||
| -rw-r--r-- | src/common/wall_clock.cpp | 15 |
2 files changed, 28 insertions, 7 deletions
diff --git a/src/common/uint128.h b/src/common/uint128.h index 83560a9ce..4780b2f9d 100644 --- a/src/common/uint128.h +++ b/src/common/uint128.h @@ -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 diff --git a/src/common/wall_clock.cpp b/src/common/wall_clock.cpp index 1545993bd..49830b8ab 100644 --- a/src/common/wall_clock.cpp +++ b/src/common/wall_clock.cpp @@ -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 |