| description | Learn more about: __mulh | |
|---|---|---|
| title | __mulh | |
| ms.date | 09/02/2019 | |
| f1_keywords |
|
|
| helpviewer_keywords |
|
|
| ms.assetid | cd2ab093-9ef6-404d-ac34-0bee033882f3 |
Microsoft Specific
Returns the high 64 bits of the product of two 64-bit signed integers.
__int64 __mulh(
__int64 a,
__int64 b
);a
[in] The first number to multiply.
b
[in] The second number to multiply.
The high 64 bits of the 128-bit result of the multiplication.
| Intrinsic | Architecture |
|---|---|
__mulh |
x64 |
Header file <intrin.h>
This routine is only available as an intrinsic.
// mulh.cpp
// processor: x64
#include <stdio.h>
#include <intrin.h>
#pragma intrinsic (__mulh)
int main()
{
__int64 a = 0x0fffffffffffffffI64;
__int64 b = 0xf0000000I64;
__int64 result = __mulh(a, b); // the high 64 bits
__int64 result2 = a * b; // the low 64 bits
printf_s(" %#I64x * %#I64x = %#I64x%I64x\n",
a, b, result, result2);
}0xfffffffffffffff * 0xf0000000 = 0xeffffffffffffff10000000
END Microsoft Specific