_mm_sign_pi8
Microsoft Specific
Emits the Supplemental Streaming SIMD Extensions 3 (SSSE3) instruction psignb. This instruction negates or clears 8-bit signed integers of a 64-bit parameter.
__m64 _mm_sign_pi8(
__m64 a,
__m64 b
);
Parameters
[in] a
A 64-bit parameter that contains eight 8-bit signed integers.[in] b
A 64-bit parameter that contains eight 8-bit signed integers.
Return value
The return value can be expressed with the following equations.
r0 := (b0 < 0) ? -a0 : ((b0 == 0) ? 0 : a0)
r1 := (b1 < 0) ? -a1 : ((b1 == 0) ? 0 : a1)
...
r7 := (b7 < 0) ? -a7 : ((b7 == 0) ? 0 : a7)
Requirements
Intrinsic |
Architecture |
|---|---|
_mm_sign_pi8 |
x86, x64 |
Header file <tmmintrin.h>
Remarks
r0-r7, a0-a7, and b0-b7 are the sequentially ordered 8-bit components of return value r and parameters a and b. r0, a0, and b0 are the least significant 8 bits.
Before you use this intrinsic, software must ensure that the underlying processor supports the instruction.
Example
#include <stdio.h>
#include <tmmintrin.h>
int main ()
{
__m64 a, b;
a.m64_i8[0] = 42;
a.m64_i8[1] = -120;
a.m64_i8[2] = 51;
a.m64_i8[3] = 31;
a.m64_i8[4] = -27;
a.m64_i8[5] = -15;
a.m64_i8[6] = -81;
a.m64_i8[7] = 29;
b.m64_i8[0] = 1;
b.m64_i8[1] = 0;
b.m64_i8[2] = -1;
b.m64_i8[3] = 127;
b.m64_i8[4] = -128;
b.m64_i8[5] = -51;
b.m64_i8[6] = 0;
b.m64_i8[7] = 1;
__m64 res = _mm_sign_pi8(a, b);
printf_s(" a\t b\t res\n%6d\t%6d\t%6d\n%6d\t%6d\t%6d\n",
a.m64_i8[0], b.m64_i8[0], res.m64_i8[0],
a.m64_i8[1], b.m64_i8[1], res.m64_i8[1]);
printf_s("%6d\t%6d\t%6d\n%6d\t%6d\t%6d\n%6d\t%6d\t%6d\n%6d\t%6d\t%6d\n",
a.m64_i8[2], b.m64_i8[2], res.m64_i8[2],
a.m64_i8[3], b.m64_i8[3], res.m64_i8[3],
a.m64_i8[4], b.m64_i8[4], res.m64_i8[4],
a.m64_i8[5], b.m64_i8[5], res.m64_i8[5]);
printf_s("%6d\t%6d\t%6d\n%6d\t%6d\t%6d\n",
a.m64_i8[6], b.m64_i8[6], res.m64_i8[6],
a.m64_i8[7], b.m64_i8[7], res.m64_i8[7]);
_mm_empty();
return 0;
}
a b res
42 1 42
-120 0 0
51 -1 -51
31 127 31
-27 -128 27
-15 -51 15
-81 0 0
29 1 29