yuzu/src/common/uint128.cpp
2020-06-18 16:29:18 -04:00

68 lines
1.6 KiB
C++

// Copyright 2019 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#ifdef _MSC_VER
#include <intrin.h>
#pragma intrinsic(_umul128)
#pragma intrinsic(_udiv128)
#endif
#include <cstring>
#include "common/uint128.h"
namespace Common {
#ifdef _MSC_VER
u64 MultiplyAndDivide64(u64 a, u64 b, u64 d) {
u128 r{};
r[0] = _umul128(a, b, &r[1]);
u64 remainder;
return _udiv128(r[1], r[0], d, &remainder);
}
#else
u64 MultiplyAndDivide64(u64 a, u64 b, u64 d) {
const u64 diva = a / d;
const u64 moda = a % d;
const u64 divb = b / d;
const u64 modb = b % d;
return diva * b + moda * divb + moda * modb / 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