api里面有没有2个longlong的安全相乘?保证不会越界

[tsys2000]

api里面有没有2个longlong的安全相乘?保证不会越界

[DentistryDoctor]

Int32x32To64是两个32位整数相乘，不能满足楼的要求。

[DentistryDoctor]

可以用下列的函数(需要包含emmintrin.h,需要目标机器支持SSE指令集)

__m128i _mm_mul_epu32(__m128i a, __m128i b);

[windyloft]

没有

[vcmute]

Int32x32To64
The Int32x32To64 function multiplies two signed 32-bit integers, returning a signed 64-bit integer result. The function performs optimally on 32-bit Windows.

LONGLONG Int32x32To64(
LONG Multiplier, // first signed 32-bit integer
LONG Multiplicand // second signed 32-bit integer
);

无符号的用
UInt32x32To64
The UInt32x32To64 function multiplies two unsigned 32-bit integers, returning an unsigned 64-bit integer result. The function performs optimally on 32-bit Windows.

ULONGLONG UInt32x32To64(
DWORD Multiplier, // first unsigned 32-bit integer
DWORD Multiplicand // second unsigned 32-bit integer
);