_mm_hadd_epi16

Microsoft Specific

Emits the Supplemental Streaming SIMD Extensions 3 (SSSE3) instruction phaddw. This instruction adds the elements of two 128-bit parameters.

__m128i _mm_hadd_epi16( 
   __m128i a,
   __m128i b
);

Parameters

• [in] a
  A 128-bit parameter that contains eight 16-bit signed integers.

• [in] b
  A 128-bit parameter contains eight 16-bit signed integers.

Return value

A 128-bit value that contains eight 16-bit signed integers. Each integer is the sum between adjacent pairs of elements in the input parameters.

The result can be expressed with the following equations:

r0 := a0 + a1
r1 := a2 + a3
r2 := a4 + a5
r3 := a6 + a7
r4 := b0 + b1
r5 := b2 + b3
r6 := b4 + b5
r7 := b6 + b7

Requirements

Header file <tmmintrin.h>

Remarks

r0-r7, a0-a7, and b0-b7 are the sequentially ordered 16-bit components of return value r and parameters a and b. r0, a0, and b0 are the least significant 16 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 ()
{
    __m128i a, b;

    a.m128i_i16[0] = -1;
    a.m128i_i16[1] = 1;
    a.m128i_i16[2] = 0;
    a.m128i_i16[3] = 8;
    a.m128i_i16[4] = -8;
    a.m128i_i16[5] = 0;
    a.m128i_i16[6] = 2;
    a.m128i_i16[7] = 2;
    b.m128i_i16[0] = -2;
    b.m128i_i16[1] = -2;
    b.m128i_i16[2] = 1000;
    b.m128i_i16[3] = 2000;
    b.m128i_i16[4] = 128;
    b.m128i_i16[5] = 32;
    b.m128i_i16[6] = 81;
    b.m128i_i16[7] = -21;

    __m128i res = _mm_hadd_epi16(a, b);

    printf_s("Original a: \t%d\t%d\t%d\t%d\n\t\t%d\t%d\t%d\t%d\n",
                a.m128i_i16[0], a.m128i_i16[1], a.m128i_i16[2], a.m128i_i16[3],
                a.m128i_i16[4], a.m128i_i16[5], a.m128i_i16[6], a.m128i_i16[7]);
    printf_s("Original b: \t%d\t%d\t%d\t%d\n\t\t%d\t%d\t%d\t%d\n",
                b.m128i_i16[0], b.m128i_i16[1], b.m128i_i16[2], b.m128i_i16[3],
                b.m128i_i16[4], b.m128i_i16[5], b.m128i_i16[6], b.m128i_i16[7]);
    printf_s("Result res: \t%d\t%d\t%d\t%d\n\t\t%d\t%d\t%d\t%d\n",
                res.m128i_i16[0], res.m128i_i16[1], res.m128i_i16[2], res.m128i_i16[3],
                res.m128i_i16[4], res.m128i_i16[5], res.m128i_i16[6], res.m128i_i16[7]);

    return 0;
}

Original a:     -1      1       0       8
                -8      0       2       2
Original b:     -2      -2      1000    2000
                128     32      81      -21
Result res:     0       8       -8      4
                -4      3000    160     60

See Also

Concepts

Compiler Intrinsics