main.cpp

#include <stdio.h>
#include <limits>

using namespace std;

extern "C" void AvxSfpCompare(double a, double b, bool results[8]);

int main(int argc, char* argv[])
{
    const int n = 4;
    const int m = 8;

    const char* inames[8] =
    {
        "vcmpeqsd", "vcmpneqsd", "vcmpltsd", "vcmplesd",
        "vcmpgtsd", "vcmpgesd", "vcmpordsd", "vcmpunordsd"
    };

    double a[n] = { 20.0, 50.0, 75.0, 42.0 };
    double b[n] = { 30.0, 40.0, 75.0, 0.0 };
    bool results[n][m];

    b[3] = numeric_limits<double>::quiet_NaN();

    printf("Results for AvxScalarFloatingPointCompare\n");

    for (int i = 0; i < n; i++)
    {
        AvxSfpCompare(a[i], b[i], results[i]);

        printf("\na: %8lf b: %8lf\n", a[i], b[i]);

        for (int j = 0; j < m; j++)
            printf("%12s = %d\n", inames[j], results[i][j]);
    }

    return 0;
}

avxfloatingpointcompare.asm

; Name:     avxfloatingpointcompare.asm
;
; Build:    g++ -c -m32 main.cpp -o main.o
;           nasm -f elf32 -o avxfloatingpointcompare.o avxfloatingpointcompare.asm
;           g++ -m32 -o avxfloatingpointcompare avxfloatingpointcompare.o main.o
;
; Source:   Modern x86 Assembly Language Programming p. 355

global AvxSfpCompare

section .text

; extern "C" void AvxSfpCompare(double a, double b, bool results[8]);
;
; Description:  The following function demonstrates use of the
;               x86-AVX compare instruction vcmpsd.
;
; Requires:     AVX

%define a       [ebp+8]
%define b       [ebp+16]
%define results [ebp+24]

AvxSfpCompare:
    push    ebp
    mov     ebp,esp

; Load argument values
    vmovsd  xmm0,a       ;xmm0 = a
    vmovsd  xmm1,b      ;xmm1 = b;
    mov     eax,results                    ;eax= ptr to results array

; Perform compare for equality
    vcmpeqsd  xmm2,xmm0,xmm1             ;perform compare operation
    vmovmskpd ecx,xmm2                  ;move result to bit 0 of ecx
    test      ecx,1                          ;test bit result
    setnz     byte[eax+0]              ;save result as C++ bool

; Perform compare for inequality.  Note that vcmpneqsd returns true
; if used with QNaN or SNaN operand values.
    vcmpneqsd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test      ecx,1
    setnz byte[eax+1]

; Perform compare for less than
    vcmpltsd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+2]

; Perform compare for less than or equal
    vcmplesd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+3]

; Perform compare for greater than
    vcmpgtsd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+4]

; Perform compare for greater than or equal
    vcmpgesd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+5]

; Perform compare for ordered
    vcmpordsd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+6]

; Perform compare for unordered
    vcmpunordsd xmm2,xmm0,xmm1
    vmovmskpd ecx,xmm2
    test ecx,1
    setnz byte[eax+7]

    pop ebp
    ret

build

g++ -c -m32 main.cpp -o main.o
nasm -f elf32 -o avxfloatingpointcompare.o avxfloatingpointcompare.asm
g++ -m32 -o avxfloatingpointcompare avxfloatingpointcompare.o main.o