_mm_roti_epi32

_mm_roti_epi32

Visual Studio 2010

Visual Studio 2010 SP1 is required.

Microsoft Specific

Generates the XOP instruction vprotd to rotate each of the doublewords in its first source by the amount specified in the second.

__m128i _mm_roti_epi32 (
   __m128i src,
   int count
);

[in] src

A 128-bit parameter that contains four 32-bit unsigned integers.

[in] count

An integer rotation count, preferably constant.

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

r[i] := (count > 0) ? rotate_left(src[i], count) : 
                      rotate_right(src[i], -count);

Intrinsic

Architecture

_mm_roti_epi32

XOP

Header file <intrin.h>

Each 32-bit unsigned integer value in src is rotated by the number of bits specified in count, and the 32-bit unsigned integer result is stored as the corresponding value in the destination. If the value in count is positive, the rotation is to the left (toward the most significant bit); otherwise, it is to the right.

The vprotd instruction has one form for constant arguments, another for non-constant arguments. If the value of count cannot be determined to be constant at compile time, the compiler will generate extra code to set up and use the non-constant version of vprotd. The constant version of vprotd is faster.

The vprotd 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, 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_roti_epi32(a, -21);
    printf_s("data:                ");
    for (i = 0; i < 4; i++) printf_s(" %08x", a.m128i_u32[i]);
    printf_s("\nrotated by  -21 gives");
    for (i = 0; i < 4; i++) printf_s(" %08x", d.m128i_u32[i]);
    printf_s("\n");
}
data:                 789abcde f0123456 789abcde f0123456
rotated by  -21 gives d5e6f3c4 91a2b780 d5e6f3c4 91a2b780

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