VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/math/fmaf.cpp@ 96810

Last change on this file since 96810 was 96407, checked in by vboxsync, 2 years ago

scm copyright and license note update

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1/* $Id: fmaf.cpp 96407 2022-08-22 17:43:14Z vboxsync $ */
2/** @file
3 * IPRT - No-CRT - fmaf().
4 */
5
6/*
7 * Copyright (C) 2022 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * The contents of this file may alternatively be used under the terms
26 * of the Common Development and Distribution License Version 1.0
27 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28 * in the VirtualBox distribution, in which case the provisions of the
29 * CDDL are applicable instead of those of the GPL.
30 *
31 * You may elect to license modified versions of this file under the
32 * terms and conditions of either the GPL or the CDDL or both.
33 *
34 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35 */
36
37
38/*********************************************************************************************************************************
39* Header Files *
40*********************************************************************************************************************************/
41#define IPRT_NO_CRT_FOR_3RD_PARTY
42#include "internal/nocrt.h"
43#include <iprt/nocrt/math.h>
44#include <iprt/assertcompile.h>
45#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
46# include <iprt/asm-amd64-x86.h>
47# include <iprt/x86.h>
48#endif
49#include <softfloat.h>
50
51
52/*********************************************************************************************************************************
53* External Symbols *
54*********************************************************************************************************************************/
55DECLASM(float) rtNoCrtMathFma3f(float r32Factor1, float r32Factor2, float r32Addend);
56DECLASM(float) rtNoCrtMathFma4f(float r32Factor1, float r32Factor2, float r32Addend);
57
58
59#undef fmaf
60float RT_NOCRT(fmaf)(float r32Factor1, float r32Factor2, float r32Addend)
61{
62 /*
63 * We prefer using native FMA instructions when available.
64 */
65#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
66 typedef enum { kCpuDetect = 0, kCpuWithFma3, kCpuWithFma4, kCpuWithoutFma } CPUFMASUPPORT;
67 static CPUFMASUPPORT volatile s_enmSup = kCpuDetect;
68 CPUFMASUPPORT enmSup = s_enmSup;
69 if (enmSup != kCpuDetect)
70 { }
71 else
72 {
73 if (ASMCpuId_ECX(1) & X86_CPUID_FEATURE_ECX_FMA)
74 enmSup = kCpuWithFma3;
75 else if (ASMCpuId_ECX(UINT32_C(0x80000001)) & X86_CPUID_AMD_FEATURE_ECX_FMA4)
76 enmSup = kCpuWithFma4;
77 else
78 enmSup = kCpuWithoutFma;
79 s_enmSup = enmSup;
80 }
81 if (enmSup == kCpuWithFma3)
82 return rtNoCrtMathFma3f(r32Factor1, r32Factor2, r32Addend);
83 if (enmSup == kCpuWithFma4)
84 return rtNoCrtMathFma4f(r32Factor1, r32Factor2, r32Addend);
85#endif
86
87 /*
88 * Fall back on SoftFloat.
89 */
90 /** @todo couldn't we just use double as a fallback here? */
91 AssertCompile(sizeof(r32Factor1) == sizeof(RTFLOAT32U));
92 softfloat_state_t State = SOFTFLOAT_STATE_INIT_DEFAULTS(); /** @todo init from MXCSR/FCW */
93 union { RTFLOAT32U Iprt; float32_t SoftFloat; } uFactor1, uFactor2, uAddend, uResult;
94 uFactor1.Iprt.r = r32Factor1;
95 uFactor2.Iprt.r = r32Factor2;
96 uAddend.Iprt.r = r32Addend;
97 uResult.SoftFloat = f32_mulAdd(uFactor1.SoftFloat, uFactor2.SoftFloat, uAddend.SoftFloat, &State);
98 return uResult.Iprt.r;
99}
100RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fmaf);
101
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