diff options
Diffstat (limited to 'src/common')
-rw-r--r-- | src/common/uint128.cpp | 11 | ||||
-rw-r--r-- | src/common/uint128.h | 9 |
2 files changed, 11 insertions, 9 deletions
diff --git a/src/common/uint128.cpp b/src/common/uint128.cpp index 8548ba808..2238a52c5 100644 --- a/src/common/uint128.cpp +++ b/src/common/uint128.cpp @@ -3,31 +3,32 @@ #pragma intrinsic(_umul128) #endif +#include <cstring> #include "common/uint128.h" namespace Common { + u128 Multiply64Into128(u64 a, u64 b) { -#ifdef _MSC_VER u128 result; +#ifdef _MSC_VER 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> Divide128On64(u128 dividend, u64 divisor) { +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 - u64 first_segment = (dividend[1] % divisor) << 32; + const u64 first_segment = (dividend[1] % divisor) << 32; accum += (first_segment / divisor) << 32; - u64 second_segment = (first_segment % divisor) << 32; + const u64 second_segment = (first_segment % divisor) << 32; accum += (second_segment / divisor); remainder += second_segment % divisor; if (remainder >= divisor) { diff --git a/src/common/uint128.h b/src/common/uint128.h index 45e384c33..52e6b46eb 100644 --- a/src/common/uint128.h +++ b/src/common/uint128.h @@ -1,13 +1,14 @@ -#include <array> -#include <cstdint> -#include <cstring> + #include <utility> #include "common/common_types.h" namespace Common { +// This function multiplies 2 u64 values and produces a u128 value; u128 Multiply64Into128(u64 a, u64 b); -std::pair<u64, u64> Divide128On64(u128 dividend, u64 divisor); +// This function divides a u128 by a u32 value and produces two u64 values: +// the result of division and the remainder +std::pair<u64, u64> Divide128On32(u128 dividend, u32 divisor); } // namespace Common |