Simplify utils::umulh64 (MSVC)

2021-04-29 00:10:38 +03:00
parent 703ec474f5
commit b1736b6411
1 changed files with 3 additions and 10 deletions
@@ -249,20 +249,13 @@ namespace utils
 	{
 #ifdef _MSC_VER
 		if (std::is_constant_evaluated())
 #endif
 		{
-			u128 a = (u32)x * (u64)(u32)y;
+			return static_cast<u64>((u128{x} * u128{y}) >> 64);
 			u128 b = (x >> 32) * (u32)y;
 			u128 c = (u32)x * (y >> 32);
 			u128 d = (x >> 32) * (y >> 32);
 			a += (b << 32);
 			a += (c << 32);
 			a.hi += d.lo;
 			return a.hi;
 		}
 #ifdef _MSC_VER
 		return __umulh(x, y);
 #else
 		return (u128{x} * u128{y}) >> 64;
 #endif
 	}