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/* $Id$ */
/** @file
* IPRT - No-CRT - fma().
*/
/*
* Copyright (C) 2022 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define IPRT_NO_CRT_FOR_3RD_PARTY
#include "internal/nocrt.h"
#include <iprt/nocrt/math.h>
#include <iprt/assertcompile.h>
#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
# include <iprt/asm-amd64-x86.h>
# include <iprt/x86.h>
#endif
#include <softfloat.h>
/*********************************************************************************************************************************
* External Symbols *
*********************************************************************************************************************************/
DECLASM(double) rtNoCrtMathFma3(double rdFactor1, double rdFactor2, double rdAddend);
DECLASM(double) rtNoCrtMathFma4(double rdFactor1, double rdFactor2, double rdAddend);
#undef fma
double RT_NOCRT(fma)(double rdFactor1, double rdFactor2, double rdAddend)
{
/*
* We prefer using native FMA instructions when available.
*/
#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
typedef enum { kCpuDetect = 0, kCpuWithFma3, kCpuWithFma4, kCpuWithoutFma } CPUFMASUPPORT;
static CPUFMASUPPORT volatile s_enmSup = kCpuDetect;
CPUFMASUPPORT enmSup = s_enmSup;
if (enmSup != kCpuDetect)
{ }
else
{
if (ASMCpuId_ECX(1) & X86_CPUID_FEATURE_ECX_FMA)
enmSup = kCpuWithFma3;
else if (ASMCpuId_ECX(UINT32_C(0x80000001)) & X86_CPUID_AMD_FEATURE_ECX_FMA4)
enmSup = kCpuWithFma4;
else
enmSup = kCpuWithoutFma;
s_enmSup = enmSup;
}
if (enmSup == kCpuWithFma3)
return rtNoCrtMathFma3(rdFactor1, rdFactor2, rdAddend);
if (enmSup == kCpuWithFma4)
return rtNoCrtMathFma4(rdFactor1, rdFactor2, rdAddend);
#endif
/*
* Fall back on SoftFloat.
*/
AssertCompile(sizeof(rdFactor1) == sizeof(RTFLOAT64U));
softfloat_state_t State = SOFTFLOAT_STATE_INIT_DEFAULTS(); /** @todo init from MXCSR/FCW */
union { RTFLOAT64U Iprt; float64_t SoftFloat; } uFactor1, uFactor2, uAddend, uResult;
uFactor1.Iprt.rd = rdFactor1;
uFactor2.Iprt.rd = rdFactor2;
uAddend.Iprt.rd = rdAddend;
uResult.SoftFloat = f64_mulAdd(uFactor1.SoftFloat, uFactor2.SoftFloat, uAddend.SoftFloat, &State);
return uResult.Iprt.rd;
}
RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fma);
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