_mm_max_epi8
Microsoft Specific
Emits the Streaming SIMD Extensions 4 (SSE4) instruction pmaxsb. This instruction chooses the larger value of the two parameters.
__m128i _mm_max_epi8(
__m128i a,
__m128i b
);
Parameters
[in] a
A 128-bit parameter that contains sixteen 8-bit signed integers.[in] b
A 128-bit parameter that contains sixteen 8-bit signed integers.
Return value
A 128-bit value that can be defined with the following equations:
r0 := (a0 > b0) ? a0 : b0
r1 := (a1 > b1) ? a1 : b1
...
r15 := (a15 > b15) ? a15 : b15
Requirements
Intrinsic |
Architecture |
|---|---|
_mm_max_epi8 |
x86, x64 |
Header file <smmintrin.h>
Remarks
r0-r15, a0-a15, and b0-b15 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 processor supports the instruction.
Example
#include <stdio.h>
#include <smmintrin.h>
int main ()
{
__m128i a, b;
a.m128i_i8[0] = 1;
a.m128i_i8[1] = 2;
a.m128i_i8[2] = 4;
a.m128i_i8[3] = 8;
a.m128i_i8[4] = 16;
a.m128i_i8[5] = 32;
a.m128i_i8[6] = 64;
a.m128i_i8[7] = 127;
a.m128i_i8[8] = -15;
a.m128i_i8[9] = 15;
a.m128i_i8[10] = 1;
a.m128i_i8[11] = -45;
a.m128i_i8[12] = 31;
a.m128i_i8[13] = -100;
a.m128i_i8[14] = 100;
a.m128i_i8[15] = -23;
b.m128i_i8[0] = 127;
b.m128i_i8[1] = -64;
b.m128i_i8[2] = 32;
b.m128i_i8[3] = -16;
b.m128i_i8[4] = 8;
b.m128i_i8[5] = -4;
b.m128i_i8[6] = 2;
b.m128i_i8[7] = -1;
b.m128i_i8[8] = 0;
b.m128i_i8[9] = 0;
b.m128i_i8[10] = -1;
b.m128i_i8[11] = -50;
b.m128i_i8[12] = 31;
b.m128i_i8[13] = -4;
b.m128i_i8[14] = 50;
b.m128i_i8[15] = -24;
__m128i res = _mm_max_epi8(a, b);
printf_s(" a\t b\t res\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n",
a.m128i_i8[0], b.m128i_i8[0], res.m128i_i8[0],
a.m128i_i8[1], b.m128i_i8[1], res.m128i_i8[1],
a.m128i_i8[2], b.m128i_i8[2], res.m128i_i8[2]);
printf_s("%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n",
a.m128i_i8[3], b.m128i_i8[3], res.m128i_i8[3],
a.m128i_i8[4], b.m128i_i8[4], res.m128i_i8[4],
a.m128i_i8[5], b.m128i_i8[5], res.m128i_i8[5],
a.m128i_i8[6], b.m128i_i8[6], res.m128i_i8[6]);
printf_s("%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n",
a.m128i_i8[7], b.m128i_i8[7], res.m128i_i8[7],
a.m128i_i8[8], b.m128i_i8[8], res.m128i_i8[8],
a.m128i_i8[9], b.m128i_i8[9], res.m128i_i8[9],
a.m128i_i8[10], b.m128i_i8[10], res.m128i_i8[10]);
printf_s("%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n%4d\t%4d\t%4d\n",
a.m128i_i8[11], b.m128i_i8[11], res.m128i_i8[11],
a.m128i_i8[12], b.m128i_i8[12], res.m128i_i8[12],
a.m128i_i8[13], b.m128i_i8[13], res.m128i_i8[13],
a.m128i_i8[14], b.m128i_i8[14], res.m128i_i8[14]);
printf_s("%4d\t%4d\t%4d\n",
a.m128i_i8[15], b.m128i_i8[15], res.m128i_i8[15]);
return 0;
}
a b res
1 127 127
2 -64 2
4 32 32
8 -16 8
16 8 16
32 -4 32
64 2 64
127 -1 127
-15 0 0
15 0 15
1 -1 1
-45 -50 -45
31 31 31
-100 -4 -4
100 50 100
-23 -24 -23