1 files changed, 23 insertions, 1 deletions
diff --git a/src/common/uint128.cpp b/src/common/uint128.cpp
index aea7f03e2..8548ba808 100644
--- a/src/common/uint128.cpp
+++ b/src/common/uint128.cpp
@@ -1,7 +1,25 @@
+#ifdef _MSC_VER
+#include <intrin.h>
+
+#pragma intrinsic(_umul128)
+#endif
+#include "common/uint128.h"
 
 namespace Common {
+u128 Multiply64Into128(u64 a, u64 b) {
+#ifdef _MSC_VER
+    u128 result;
+    result[0] = _umul128(a, b, &result[1]);
+#else
+    unsigned __int128 tmp = a;
+    tmp *= b;
+    u128 result;
+    std::memcpy(&result, &tmp, sizeof(u128));
+#endif
+    return result;
+}
 
-std::pair<u64, u64> udiv128(u128 dividend, u64 divisor) {
+std::pair<u64, u64> Divide128On64(u128 dividend, u64 divisor) {
     u64 remainder = dividend[0] % divisor;
     u64 accum = dividend[0] / divisor;
     if (dividend[1] == 0)
@@ -12,6 +30,10 @@ std::pair<u64, u64> udiv128(u128 dividend, u64 divisor) {
     u64 second_segment = (first_segment % divisor) << 32;
     accum += (second_segment / divisor);
     remainder += second_segment % divisor;
+    if (remainder >= divisor) {
+        accum++;
+        remainder -= divisor;
+    }
     return {accum, remainder};
 }