early-access version 1331

src/common/uint128.cpp

@@ -38,4 +38,34 @@ u64 MultiplyAndDivide64(u64 a, u64 b, u64 d) {
 
 #endif
 
+u128 Multiply64Into128(u64 a, u64 b) {
+    u128 result;
+#ifdef _MSC_VER
+    result[0] = _umul128(a, b, &result[1]);
+#else
+    unsigned __int128 tmp = a;
+    tmp *= b;
+    std::memcpy(&result, &tmp, sizeof(u128));
+#endif
+    return result;
+}
+
+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

src/common/uint128.h

@@ -12,4 +12,11 @@ namespace Common {
 // This function multiplies 2 u64 values and divides it by a u64 value.
 [[nodiscard]] u64 MultiplyAndDivide64(u64 a, u64 b, u64 d);
 
+// This function multiplies 2 u64 values and produces a u128 value;
+[[nodiscard]] u128 Multiply64Into128(u64 a, u64 b);
+
+// This function divides a u128 by a u32 value and produces two u64 values:
+// the result of division and the remainder
+[[nodiscard]] std::pair<u64, u64> Divide128On32(u128 dividend, u32 divisor);
+
 } // namespace Common

src/common/wall_clock.cpp

@@ -2,6 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include "common/uint128.h"
 #include "common/wall_clock.h"
 
 #ifdef ARCHITECTURE_x86_64
@@ -40,11 +41,16 @@ public:
     }
 
     u64 GetClockCycles() override {
-        return GetTimeNS().count() * (emulated_clock_frequency / 1000) / 1000000;
+        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 GetTimeNS().count() * (emulated_cpu_frequency / 1000) / 1000000;
+        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 {