_mm_sha_epi32

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 vpshad to do an arithmetic shift of each of the doublewords in its first source by an amount specified in the second.

__m128i _mm_sha_epi32 (
   __m128i src,
   __m128i counts
);

Parameters

[in] src
A 128-bit parameter that contains four 32-bit signed integers.
[in] counts
A 128-bit parameter that contains sixteen 8-bit signed integers.

Return value

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

r[i] := (counts[4*i] >= 0) ? src[i] << counts[4*i] :
                             src[i] >> -counts[4*i]);

Requirements

Intrinsic	Architecture
_mm_sha_epi32	XOP

Header file <intrin.h>

Remarks

Each 32-bit signed integer value in src is shifted by the number of bits specified by the value in the byte of counts corresponding to its low-order byte, and the 32-bit signed integer result is stored as the corresponding value in the destination. If the value in counts is positive, the shift is to the left (toward the most significant bit) and zeros are shifted in at the right end; otherwise, it is to the right and zeros are shifted in at the left end. If a shift count is greater than 31 the corresponding result value is 0; if a shift count is less than -31, the result is -1 if the value in src is negative, 0 otherwise. The other values in counts are ignored.

The vpshad 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, b, d;
    int i, j;
    unsigned int temp;
    for (i = 0; i < 4; i++) {
        temp = 0;
        for (j = 0; j < 8; j++) {
            temp = temp << 4 | (8*i + j + 7) % 16;
        }
        a.m128i_u32[i] = temp;
        b.m128i_i8[4*i] = 11*i - 21;
    }
    d = _mm_sha_epi32(a, b);
    printf_s("data:       ");
    for (i = 0; i < 4; i++) printf_s(" %08x", a.m128i_u32[i]);
    printf_s("\nshifted by  ");
    for (i = 0; i < 4; i++) printf_s(" %8d", b.m128i_i8[4*i]);
    printf_s("\ngives       ");
    for (i = 0; i < 4; i++) printf_s(" %08x", d.m128i_u32[i]);
    printf_s("\n");
}

data:        789abcde f0123456 789abcde f0123456
shifted by        -21      -10        1       12
gives        000003c4 fffc048d f13579bc 23456000

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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