Microsoft Specific

Emits the Streaming SIMD Extensions 4 (SSE4) instruction blendps. This instruction blends packed single precision floating point values.

__m128 _mm_blend_ps( 
   __m128 a,
   __m128 b,
   const int mask 


  • [in] a
    A 128-bit parameter that contains four 32-bit floating point values to be blended.

  • [in] b
    A 128-bit parameter that contains four 32-bit floating point values to be blended.

  • [in] mask
    A constant mask that selects components for the blend operation.

Return value

r0 := (mask0 == 0) ? a0 : b0
r1 := (mask1 == 0) ? a1 : b1
r2 := (mask2 == 0) ? a2 : b2
r3 := (mask3 == 0) ? a3 : b3





x86, x64

Header file <smmintrin.h>


The return value r and parameters a and b each consist of 128 bits. r0-r3, a0-a3, and b0-b3 are the sequentially ordered 32-bit components of these parameters, where r0, a0, and b0 indicate the least significant 32 bits.

mask0-3 are the four least significant bits of parameter mask.

Before using this intrinsic, software must ensure that the processor supports the instruction.


#include <stdio.h>
#include <smmintrin.h>

int main () {
    __m128 a, b;
    const int mask = 12;

    a.m128_u32[3] = 0xFFEEDDCC;
    a.m128_u32[2] = 0xBBAA9988;
    a.m128_u32[1] = 0x77665544;
    a.m128_u32[0] = 0x33221100;
    b.m128_u32[3] = 0x11112222;
    b.m128_u32[2] = 0x33334444;
    b.m128_u32[1] = 0x55556666;
    b.m128_u32[0] = 0x77778888;

    __m128 res = _mm_blend_ps( a, b, mask );

    printf_s("Original a: 0x%08x, 0x%08x, 0x%08x, 0x%08x\n",
        a.m128_u32[3], a.m128_u32[2], a.m128_u32[1], a.m128_u32[0]);
    printf_s("Original b: 0x%08x, 0x%08x, 0x%08x, 0x%08x\n",
        b.m128_u32[3], b.m128_u32[2], b.m128_u32[1], b.m128_u32[0]);
    printf_s("Result res: 0x%08x, 0x%08x, 0x%08x, 0x%08x\n",
        res.m128_u32[3], res.m128_u32[2], 
        res.m128_u32[1], res.m128_u32[0]);

    return 0;

Original a: 0xffeeddcc, 0xbbaa9988, 0x77665544, 0x33221100 Original b: 0x11112222, 0x33334444, 0x55556666, 0x77778888 Result res: 0x11112222, 0x33334444, 0x77665544, 0x33221100

See Also


Compiler Intrinsics