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