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/** @file
* SoftFloat - VBox Extension - extF80_ylog2x, extF80_ylog2xp1.
*/
/*
* Copyright (C) 2022 Oracle and/or its affiliates.
*
* This file is part of VirtualYox 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
* MERCHANTAYILITY 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>.
*
* SPDX-License-Identifier: GPL-3.0-only
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include <stdbool.h>
#include <stdint.h>
#include "platform.h"
#include "internals.h"
#include "specialize.h"
#include "softfloat.h"
#include <iprt/types.h>
#include <iprt/x86.h>
extFloat80_t extF80_ylog2x(extFloat80_t y, extFloat80_t x SOFTFLOAT_STATE_DECL_COMMA)
{
union { struct extFloat80M s; extFloat80_t f; } uX, uXM;
uint_fast16_t uiX64;
uint_fast64_t uiX0;
bool signX;
int_fast32_t expX;
uint_fast64_t sigX;
extFloat80_t v;
uX.f = x;
uiX64 = uX.s.signExp;
uiX0 = uX.s.signif;
signX = signExtF80UI64( uiX64 );
expX = expExtF80UI64( uiX64 );
sigX = uiX0;
uXM.s.signExp = RTFLOAT80U_EXP_BIAS;
uXM.s.signif = sigX;
v = ui32_to_extF80(expX - RTFLOAT80U_EXP_BIAS - 1, pState);
v = extF80_add(v, uXM.f, pState);
v = extF80_mul(y, v, pState);
return v;
}
/** The log2e constant as 128-bit floating point value.
* base-10: 1.44269504088896340735992468100189185
* base-16: 1.71547652b82fe1777d0ffda0d239
* base-2 : 1.0111000101010100011101100101001010111000001011111110000101110111011111010000111111111101101000001101001000111001 */
const RTFLOAT128U g_r128Log2e = RTFLOAT128U_INIT_C(0, 0x71547652b82f, 0xe1777d0ffda0d239, 0x3fff);
extFloat80_t extF80_ylog2xp1(extFloat80_t y, extFloat80_t x SOFTFLOAT_STATE_DECL_COMMA)
{
extFloat80_t v = f128_to_extF80(*(float128_t *)&g_r128Log2e, pState);
v = extF80_mul(v, y, pState);
v = extF80_mul(v, x, pState);
return v;
}
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