_mm_com_epu32

Visual Studio 2010

Visual Studio 2010 SP1 is required.

Microsoft Specific

Generates the XOP instruction vpcomud to return a bitmask generated by a doubleword-by-doubleword unsigned comparison of its first two sources using the condition given by the third source.

__m128i _mm_com_epu32 (
   __m128i src1,
   __m128i src2,
   int condition
); 

[in] src1

Packed 128-bit array of four 32-bit unsigned integers.

[in] src2

Packed 128-bit array of four 32-bit unsigned integers.

[in] condition

A 32-bit integer condition to be used in the comparison. Legal values are 0 through 7.

A packed 128-bit array r of four 32-bit unsigned integers, each of which is either 0x00000000 or 0xFFFFFFFF. If cond is the logical operator implied by the value of condition, then

r[i] := src1[i] cond src2[i] ? 0xFFFFFFFF : 0x00000000;

Intrinsic

Architecture

_mm_com_epu32

XOP

Header file <intrin.h>

This instruction compares each doubleword of src1 to the corresponding doubleword of src2, using the comparison operator described by condition. (Each pair of doublewords uses the same comparison operator.) The legal values condition are 0 through 7. By including <intrin.h> you will be able to use the following names rather than numerical values for condition:

Integer Value

Symbolic Name

Meaning

0

_MM_PCOMCTRL_LT

r[i] = (src1[i] < src2[i]) ? 0xFFFFFFFF : 0x00000000

1

_MM_PCOMCTRL_LE

r[i] = (src1[i] <= src2[i]) ? 0xFFFFFFFF : 0x00000000

2

_MM_PCOMCTRL_GT

r[i] = (src1[i] > src2[i]) ? 0xFFFFFFFF : 0x00000000

3

_MM_PCOMCTRL_GE

r[i] = (src1[i] >= src2[i]) ? 0xFFFFFFFF : 0x00000000

4

_MM_PCOMCTRL_EQ

r[i] = (src1[i] == src2[i]) ? 0xFFFFFFFF : 0x00000000

5

_MM_PCOMCTRL_NEQ

r[i] = (src1[i] != src2[i]) ? 0xFFFFFFFF : 0x00000000

6

_MM_PCOMCTRL_FALSE

r[i] = 0x00000000 (mask of all zeros)

7

_MM_PCOMCTRL_TRUE

r[i] = 0xFFFFFFFF (mask of all ones)

If you prefer, you may use the following macros, which will be defined when <intrin.h> is included:

Macro

Meaning

_mm_comlt_epu32(src1, src2)

_mm_com_epu32(src1, src2, 0)

_mm_comle_epu32(src1, src2)

_mm_com_epu32(src1, src2, 1)

_mm_comgt_epu32(src1, src2)

_mm_com_epu32(src1, src2, 2)

_mm_comge_epu32(src1, src2)

_mm_com_epu32(src1, src2, 3)

_mm_comeq_epu32(src1, src2)

_mm_com_epu32(src1, src2, 4)

_mm_comneq_epu32(src1, src2)

_mm_com_epu32(src1, src2, 5)

_mm_comfalse_epu32(src1, src2)

_mm_com_epu32(src1, src2, 6)

_mm_comtrue_epu32(src1, src2)

_mm_com_epu32(src1, src2, 7)

The vpcomud 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>
main()
{
    __m128i a, b, d;
    int i;
    for (i = 0; i < 4; i++) {
        a.m128i_i32[i] = 1000*i - 1500;
        b.m128i_i32[i] = 2000*i - 2500;
    }
    printf("src1:       ");
    for (i = 0; i < 4; i++) printf_s("   %10u", a.m128i_u32[i]);
    printf_s("\nsrc2:       ");
    for (i = 0; i < 4; i++) printf_s("   %10u", b.m128i_u32[i]);
    printf_s("\n>   mask:   ");
    d = _mm_com_epi32(a, b, _MM_PCOMCTRL_GT);
    for (i = 0; i < 4; i++) printf_s("     %08x", d.m128i_u32[i]);
    printf_s("\nfalse mask: ");
    d = _mm_com_epi32(a, b, _MM_PCOMCTRL_FALSE);
    for (i = 0; i < 4; i++) printf_s("     %08x", d.m128i_u32[i]);
    printf("\n");
}
src1:          4294965796   4294966796          500         1500
src2:          4294964796   4294966796         1500         3500
>   mask:        ffffffff     00000000     00000000     00000000
false mask:      00000000     00000000     00000000     00000000

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