_mm_macc_sd

[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 FMA4 XMM instruction vfmaddsd to perform a single-round double-precision floating-point multiply-add of the low-order floating-point values of its sources.

__m128d _mm_macc_sd (
   __m128d src1,
   __m128d src2,
   __m128d src3
); 

Parameters

• [in] src1
  A 128-bit parameter that contains a 64-bit floating-point value in the low quadword.

• [in] src2
  A 128-bit parameter that contains a 64-bit floating-point value in the low quadword.

• [in] src3
  A 128-bit parameter that contains a 64-bit floating-point value in the low quadword.

Return value

A 128-bit result r that contains two 64-bit floating-point values.

r[0] := src1[0] * src2[0] + src3[0];
r[1] := 0.;

Requirements

Header file <intrin.h>

Remarks

The low-order double-precision floating-point value in src1 is multiplied by the corresponding value in src2 and added to the corresponding value in src3, and the result is stored as the corresponding value in the destination. The other values in src1, src2, and src3 are ignored, and the high-order double-precision floating-point value of the result is set to 0. The multiply-add is performed with a single round at the end, as if intermediate results were computed to infinite precision.

The vfmaddsd instruction is part of the FMA4 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 16 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()
{
    __m128d a, b, c, d;
    int i;
    for (i = 0; i < 2; i++) {
        a.m128d_f64[i] = i;
        b.m128d_f64[i] = 2.;
        c.m128d_f64[i] = 3.;
    }
    d = _mm_macc_sd(a, b, c);
    for (i = 0; i < 2; i++) printf_s(" %.3lf", d.m128d_f64[i]);
    printf_s("\n");
}

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See Also

Reference

_mm256_macc_pd

_mm_macc_pd

_mm_macc_ss

_mm_nmacc_sd

_mm_msub_sd

_mm_nmsub_sd

__cpuid, __cpuidex

FMA4 Intrinsics Added for Visual Studio 2010 SP1

Change History