| 1 | /* $Id: frexpf.cpp 96298 2022-08-18 14:28:28Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - No-CRT - frexpf().
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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 | #include <iprt/nocrt/limits.h>
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| 36 |
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| 37 |
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| 38 | /* Similar to the fxtract instruction. */
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| 39 | #undef frexpf
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| 40 | float RT_NOCRT(frexpf)(float rfValue, int *piExp)
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| 41 | {
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| 42 | RTFLOAT32U Value;
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| 43 | AssertCompile(sizeof(Value) == sizeof(rfValue));
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| 44 | Value.r = rfValue;
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| 45 |
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| 46 | if (RTFLOAT32U_IS_NORMAL(&Value))
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| 47 | {
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| 48 | *piExp = (int)Value.s.uExponent - RTFLOAT32U_EXP_BIAS + 1;
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| 49 | Value.s.uExponent = RTFLOAT32U_EXP_BIAS - 1;
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| 50 | }
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| 51 | else if (RTFLOAT32U_IS_ZERO(&Value))
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| 52 | {
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| 53 | *piExp = 0;
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| 54 | return rfValue;
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| 55 | }
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| 56 | else if (RTFLOAT32U_IS_SUBNORMAL(&Value))
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| 57 | {
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| 58 | int iExp = -RTFLOAT32U_EXP_BIAS + 1;
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| 59 | uint32_t uFraction = Value.s.uFraction;
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| 60 | while (!(uFraction & RT_BIT_32(RTFLOAT32U_FRACTION_BITS)))
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| 61 | {
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| 62 | iExp--;
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| 63 | uFraction <<= 1;
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| 64 | }
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| 65 | Value.s.uFraction = uFraction;
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| 66 | Value.s.uExponent = RTFLOAT32U_EXP_BIAS - 1;
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| 67 | *piExp = iExp + 1;
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| 68 | }
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| 69 | else /* NaN, Inf */
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| 70 | {
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| 71 | *piExp = Value.s.fSign ? INT_MIN : INT_MAX;
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| 72 | return rfValue;
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| 73 | }
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| 74 | return Value.r;
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| 75 | }
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| 76 | RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(frexpf);
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| 77 |
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