41 lines
1 KiB
C++
41 lines
1 KiB
C++
#ifdef _MSC_VER
|
|
#include <intrin.h>
|
|
|
|
#pragma intrinsic(_umul128)
|
|
#endif
|
|
#include <cstring>
|
|
#include "common/uint128.h"
|
|
|
|
namespace Common {
|
|
|
|
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
|