_mm_haddw_epi8

Artigo
07/22/2011

[Note: This document describes a pre-release version of Visual Studio 2010 SP1 and may be revised in any later version.]

Visual Studio 2010 SP1 is required.

Microsoft Specific

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

__m128i _mm_haddw_epi8 (
   __m128i src
);

Parameters

[in] src
A 128-bit parameter that contains sixteen 8-bit signed integers.

Return value

A 128-bit result r that contains eight 16-bit signed integers.

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

Requirements

Intrinsic	Architecture
_mm_haddw_epi8	XOP

Header file <intrin.h>

Remarks

Each of the eight even-odd indexed pairs of 8-bit signed integer values in src is added to produce a 16-bit signed integer result that is stored as the corresponding value in the destination.

The vphaddbw 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.

Example

#include <stdio.h>
#include <intrin.h>
int main()
{
    __m128i a, d;
    int i;
    for (i = 0; i < 16; i++) {
        a.m128i_i8[i] = i - 8;
    }
    d = _mm_haddw_epi8(a);
    for (i = 0; i < 8; i++) printf_s(" %d", d.m128i_i16[i]);
    printf_s("\n");
}

-15 -11 -7 -3 1 5 9 13

Change History

Date	History	Reason
March 2011	Added this content.	SP1 feature change.

March 2011

Added this content.

SP1 feature change.

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