179 lines
7.2 KiB
C
179 lines
7.2 KiB
C
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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3e, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2017 The Regents of the University of
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California. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "softfloat.h"
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void
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softfloat_roundPackMToF128M(
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bool sign, int32_t exp, uint32_t *extSigPtr, uint32_t *zWPtr )
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{
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uint_fast8_t roundingMode;
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bool roundNearEven;
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uint32_t sigExtra;
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bool doIncrement, isTiny;
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static const uint32_t maxSig[4] =
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INIT_UINTM4( 0x0001FFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF );
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uint32_t ui, uj;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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roundingMode = softfloat_roundingMode;
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roundNearEven = (roundingMode == softfloat_round_near_even);
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sigExtra = extSigPtr[indexWordLo( 5 )];
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doIncrement = (0x80000000 <= sigExtra);
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if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
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doIncrement =
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(roundingMode
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== (sign ? softfloat_round_min : softfloat_round_max))
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&& sigExtra;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( 0x7FFD <= (uint32_t) exp ) {
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if ( exp < 0 ) {
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/*----------------------------------------------------------------
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*----------------------------------------------------------------*/
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isTiny =
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(softfloat_detectTininess
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== softfloat_tininess_beforeRounding)
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|| (exp < -1)
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|| ! doIncrement
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|| (softfloat_compare128M(
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extSigPtr + indexMultiwordHi( 5, 4 ), maxSig )
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< 0);
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softfloat_shiftRightJam160M( extSigPtr, -exp, extSigPtr );
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exp = 0;
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sigExtra = extSigPtr[indexWordLo( 5 )];
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if ( isTiny && sigExtra ) {
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softfloat_raiseFlags( softfloat_flag_underflow );
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}
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doIncrement = (0x80000000 <= sigExtra);
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if (
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! roundNearEven
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&& (roundingMode != softfloat_round_near_maxMag)
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) {
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doIncrement =
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(roundingMode
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== (sign ? softfloat_round_min : softfloat_round_max))
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&& sigExtra;
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}
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} else if (
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(0x7FFD < exp)
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|| ((exp == 0x7FFD) && doIncrement
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&& (softfloat_compare128M(
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extSigPtr + indexMultiwordHi( 5, 4 ), maxSig )
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== 0))
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) {
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/*----------------------------------------------------------------
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*----------------------------------------------------------------*/
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softfloat_raiseFlags(
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softfloat_flag_overflow | softfloat_flag_inexact );
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if (
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roundNearEven
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|| (roundingMode == softfloat_round_near_maxMag)
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|| (roundingMode
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== (sign ? softfloat_round_min : softfloat_round_max))
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) {
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ui = packToF128UI96( sign, 0x7FFF, 0 );
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uj = 0;
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} else {
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ui = packToF128UI96( sign, 0x7FFE, 0x0000FFFF );
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uj = 0xFFFFFFFF;
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}
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zWPtr[indexWordHi( 4 )] = ui;
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zWPtr[indexWord( 4, 2 )] = uj;
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zWPtr[indexWord( 4, 1 )] = uj;
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zWPtr[indexWord( 4, 0 )] = uj;
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return;
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}
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uj = extSigPtr[indexWord( 5, 1 )];
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if ( sigExtra ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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#ifdef SOFTFLOAT_ROUND_ODD
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if ( roundingMode == softfloat_round_odd ) {
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uj |= 1;
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goto noIncrementPackReturn;
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}
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#endif
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}
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if ( doIncrement ) {
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++uj;
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if ( uj ) {
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if ( ! (sigExtra & 0x7FFFFFFF) && roundNearEven ) uj &= ~1;
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zWPtr[indexWord( 4, 2 )] = extSigPtr[indexWord( 5, 3 )];
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zWPtr[indexWord( 4, 1 )] = extSigPtr[indexWord( 5, 2 )];
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zWPtr[indexWord( 4, 0 )] = uj;
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ui = extSigPtr[indexWordHi( 5 )];
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} else {
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zWPtr[indexWord( 4, 0 )] = uj;
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ui = extSigPtr[indexWord( 5, 2 )] + 1;
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zWPtr[indexWord( 4, 1 )] = ui;
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uj = extSigPtr[indexWord( 5, 3 )];
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if ( ui ) {
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zWPtr[indexWord( 4, 2 )] = uj;
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ui = extSigPtr[indexWordHi( 5 )];
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} else {
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++uj;
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zWPtr[indexWord( 4, 2 )] = uj;
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ui = extSigPtr[indexWordHi( 5 )];
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if ( ! uj ) ++ui;
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}
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}
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} else {
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noIncrementPackReturn:
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zWPtr[indexWord( 4, 0 )] = uj;
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ui = extSigPtr[indexWord( 5, 2 )];
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zWPtr[indexWord( 4, 1 )] = ui;
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uj |= ui;
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ui = extSigPtr[indexWord( 5, 3 )];
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zWPtr[indexWord( 4, 2 )] = ui;
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uj |= ui;
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ui = extSigPtr[indexWordHi( 5 )];
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uj |= ui;
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if ( ! uj ) exp = 0;
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}
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zWPtr[indexWordHi( 4 )] = packToF128UI96( sign, exp, ui );
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}
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