# Shuffle Intrinsics

These Supplemental Streaming SIMD Extensions 3 (SSSE3) intrinsics are used to perform shuffle operations. The prototypes for these intrinsics are in tmmintrin.h.

To use these intrinsics, include the immintrin.h file as follows:

    #include <immintrin.h>

## _mm_shuffle_epi8

extern __m128i _mm_shuffle_epi8(__m128i a, __m128i b);

Shuffle bytes from a according to contents of b.

Interpreting a, b, and r as arrays of unsigned 8-bit integers:

    for (i = 0; i < 16; i++){
     if (b[i] & 0x80){
      r[i] =  0;
     }
     else {
      r[i] = a[b[i] & 0x0F];
     }
    }

## _mm_shuffle_pi8

extern __m64 _mm_shuffle_pi8(__m64 a, __m64 b);

Shuffle bytes from a according to contents of b.

Interpreting a, b, and r as arrays of unsigned 8-bit integers:

    for (i = 0; i < 8; i++){
     if (b[i] & 0x80){
      r[i] =  0;
     }
    else {
     r[i] = a[b[i] & 0x07];
     }
    }

Parent topic: Intrinsics for Intel® Supplemental Streaming SIMD Extensions 3 (SSSE3)