_mm_haddd_epi16

Visual Studio 2010

Visual Studio 2010 SP1 is required.

Microsoft Specific

Generates the XOP instruction vphaddwd to perform an integer horizontal add of its source.

__m128i _mm_haddd_epi16 (
   __m128i src
);

[in] src

A 128-bit parameter that contains eight 16-bit signed integers.

A 128-bit result r that contains four 32-bit signed integers.

r[i] := src[2*i] + src[2*i+1];

Intrinsic

Architecture

_mm_haddd_epi16

XOP

Header file <intrin.h>

Each of the four even-odd indexed pairs of 16-bit signed integer values in src is added to produce a 32-bit signed integer result that is stored as the corresponding value in the destination. No overflow is possible in this instruction.

The vphaddwd instruction is part of the XOP family of instructions. Before you use this intrinsic, you must ensure that the processor supports this instruction. To determine hardware support for this instruction, call the __cpuid intrinsic with InfoType = 0x80000001 and check bit 11 of CPUInfo[2] (ECX). This bit is 1 when the instruction is supported, and 0 otherwise.

#include <stdio.h>
#include <intrin.h>
int main()
{
    __m128i a, d;
    int i;
    for (i = 0; i < 2; i++) {
        a.m128i_i16[4*i] = -128;
        a.m128i_i16[4*i+1] = i-128;
        a.m128i_i16[4*i+2] = 10*i;
        a.m128i_i16[4*i+3] = 127;
    }
    d = _mm_haddd_epi16(a);
    for (i = 0; i < 4; i++) printf_s(" %d", d.m128i_i32[i]);
    printf_s("\n");
}
-256 127 -255 137

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