| 1 | /* $Id: fmaf.cpp 96108 2022-08-08 11:16:23Z 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 Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | */
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| 26 |
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| 27 |
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| 28 | /*********************************************************************************************************************************
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| 29 | * Header Files *
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| 30 | *********************************************************************************************************************************/
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| 31 | #define IPRT_NO_CRT_FOR_3RD_PARTY
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| 32 | #include "internal/nocrt.h"
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| 33 | #include <iprt/nocrt/math.h>
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| 34 | #include <iprt/assertcompile.h>
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| 35 | #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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| 36 | # include <iprt/asm-amd64-x86.h>
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| 37 | # include <iprt/x86.h>
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| 38 | #endif
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| 39 | #include <softfloat.h>
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| 40 |
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| 41 |
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| 42 | /*********************************************************************************************************************************
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| 43 | * External Symbols *
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| 44 | *********************************************************************************************************************************/
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| 45 | DECLASM(float) rtNoCrtMathFma3f(float r32Factor1, float r32Factor2, float r32Addend);
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| 46 | DECLASM(float) rtNoCrtMathFma4f(float r32Factor1, float r32Factor2, float r32Addend);
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| 47 |
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| 48 |
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| 49 | #undef fmaf
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| 50 | float RT_NOCRT(fmaf)(float r32Factor1, float r32Factor2, float r32Addend)
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| 51 | {
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| 52 | /*
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| 53 | * We prefer using native FMA instructions when available.
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| 54 | */
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| 55 | #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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| 56 | typedef enum { kCpuDetect = 0, kCpuWithFma3, kCpuWithFma4, kCpuWithoutFma } CPUFMASUPPORT;
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| 57 | static CPUFMASUPPORT volatile s_enmSup = kCpuDetect;
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| 58 | CPUFMASUPPORT enmSup = s_enmSup;
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| 59 | if (enmSup != kCpuDetect)
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| 60 | { }
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| 61 | else
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| 62 | {
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| 63 | if (ASMCpuId_ECX(1) & X86_CPUID_FEATURE_ECX_FMA)
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| 64 | enmSup = kCpuWithFma3;
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| 65 | else if (ASMCpuId_ECX(UINT32_C(0x80000001)) & X86_CPUID_AMD_FEATURE_ECX_FMA4)
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| 66 | enmSup = kCpuWithFma4;
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| 67 | else
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| 68 | enmSup = kCpuWithoutFma;
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| 69 | s_enmSup = enmSup;
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| 70 | }
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| 71 | if (enmSup == kCpuWithFma3)
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| 72 | return rtNoCrtMathFma3f(r32Factor1, r32Factor2, r32Addend);
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| 73 | if (enmSup == kCpuWithFma4)
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| 74 | return rtNoCrtMathFma4f(r32Factor1, r32Factor2, r32Addend);
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| 75 | #endif
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| 76 |
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| 77 | /*
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| 78 | * Fall back on SoftFloat.
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| 79 | */
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| 80 | /** @todo couldn't we just use double as a fallback here? */
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| 81 | AssertCompile(sizeof(r32Factor1) == sizeof(RTFLOAT32U));
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| 82 | softfloat_state_t State = SOFTFLOAT_STATE_INIT_DEFAULTS(); /** @todo init from MXCSR/FCW */
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| 83 | union { RTFLOAT32U Iprt; float32_t SoftFloat; } uFactor1, uFactor2, uAddend, uResult;
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| 84 | uFactor1.Iprt.r = r32Factor1;
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| 85 | uFactor2.Iprt.r = r32Factor2;
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| 86 | uAddend.Iprt.r = r32Addend;
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| 87 | uResult.SoftFloat = f32_mulAdd(uFactor1.SoftFloat, uFactor2.SoftFloat, uAddend.SoftFloat, &State);
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| 88 | return uResult.Iprt.r;
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| 89 | }
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| 90 | RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fmaf);
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| 91 |
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