Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
224 lines
7.5 KiB
C
224 lines
7.5 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 "specialize.h"
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#include "softfloat.h"
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#ifdef SOFTFLOAT_FAST_INT64
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void
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f128M_roundToInt(
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const float128_t *aPtr,
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uint_fast8_t roundingMode,
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bool exact,
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float128_t *zPtr
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)
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{
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*zPtr = f128_roundToInt( *aPtr, roundingMode, exact );
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}
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#else
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void
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f128M_roundToInt(
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const float128_t *aPtr,
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uint_fast8_t roundingMode,
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bool exact,
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float128_t *zPtr
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)
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{
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const uint32_t *aWPtr;
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uint32_t *zWPtr;
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uint32_t ui96;
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int32_t exp;
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uint32_t sigExtra;
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bool sign;
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uint_fast8_t bitPos;
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bool roundNear;
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unsigned int index, lastIndex;
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bool extra;
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uint32_t wordA, bit, wordZ;
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uint_fast8_t carry;
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uint32_t extrasMask;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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aWPtr = (const uint32_t *) aPtr;
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zWPtr = (uint32_t *) zPtr;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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ui96 = aWPtr[indexWordHi( 4 )];
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exp = expF128UI96( ui96 );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( exp < 0x3FFF ) {
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zWPtr[indexWord( 4, 2 )] = 0;
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zWPtr[indexWord( 4, 1 )] = 0;
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zWPtr[indexWord( 4, 0 )] = 0;
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sigExtra = aWPtr[indexWord( 4, 2 )];
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if ( !sigExtra ) {
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sigExtra = aWPtr[indexWord( 4, 1 )] | aWPtr[indexWord( 4, 0 )];
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}
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if ( !sigExtra && !(ui96 & 0x7FFFFFFF) ) goto ui96;
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if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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sign = signF128UI96( ui96 );
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switch ( roundingMode ) {
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case softfloat_round_near_even:
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if ( !fracF128UI96( ui96 ) && !sigExtra ) break;
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case softfloat_round_near_maxMag:
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if ( exp == 0x3FFE ) goto mag1;
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break;
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case softfloat_round_min:
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if ( sign ) goto mag1;
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break;
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case softfloat_round_max:
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if ( !sign ) goto mag1;
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break;
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#ifdef SOFTFLOAT_ROUND_ODD
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case softfloat_round_odd:
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goto mag1;
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#endif
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}
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ui96 = packToF128UI96( sign, 0, 0 );
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goto ui96;
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mag1:
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ui96 = packToF128UI96( sign, 0x3FFF, 0 );
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goto ui96;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( 0x406F <= exp ) {
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if (
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(exp == 0x7FFF)
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&& (fracF128UI96( ui96 )
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|| (aWPtr[indexWord( 4, 2 )] | aWPtr[indexWord( 4, 1 )]
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| aWPtr[indexWord( 4, 0 )]))
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) {
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softfloat_propagateNaNF128M( aWPtr, 0, zWPtr );
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return;
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}
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zWPtr[indexWord( 4, 2 )] = aWPtr[indexWord( 4, 2 )];
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zWPtr[indexWord( 4, 1 )] = aWPtr[indexWord( 4, 1 )];
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zWPtr[indexWord( 4, 0 )] = aWPtr[indexWord( 4, 0 )];
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goto ui96;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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bitPos = 0x406F - exp;
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roundNear =
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(roundingMode == softfloat_round_near_maxMag)
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|| (roundingMode == softfloat_round_near_even);
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bitPos -= roundNear;
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index = indexWordLo( 4 );
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lastIndex = indexWordHi( 4 );
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extra = 0;
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for (;;) {
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wordA = aWPtr[index];
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if ( bitPos < 32 ) break;
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if ( wordA ) extra = 1;
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zWPtr[index] = 0;
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index += wordIncr;
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bitPos -= 32;
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}
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bit = (uint32_t) 1<<bitPos;
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if ( roundNear ) {
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wordZ = wordA + bit;
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carry = (wordZ < wordA);
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bit <<= 1;
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extrasMask = bit - 1;
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if ( exact && (extra || (wordA & extrasMask)) ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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if (
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(roundingMode == softfloat_round_near_even)
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&& !extra && !(wordZ & extrasMask)
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) {
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if ( !bit ) {
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zWPtr[index] = wordZ;
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index += wordIncr;
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wordZ = aWPtr[index] + carry;
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carry &= !wordZ;
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zWPtr[index] = wordZ & ~1;
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goto propagateCarry;
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}
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wordZ &= ~bit;
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}
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} else {
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wordZ = wordA;
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carry = 0;
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extrasMask = bit - 1;
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if ( extra || (wordA & extrasMask) ) {
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if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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if (
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roundingMode
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== (signF128UI96( ui96 ) ? softfloat_round_min
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: softfloat_round_max)
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) {
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wordZ += bit;
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carry = (wordZ < wordA);
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#ifdef SOFTFLOAT_ROUND_ODD
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} else if ( roundingMode == softfloat_round_odd ) {
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wordZ |= bit;
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#endif
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}
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}
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}
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wordZ &= ~extrasMask;
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zWPtr[index] = wordZ;
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propagateCarry:
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while ( index != lastIndex ) {
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index += wordIncr;
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wordZ = aWPtr[index] + carry;
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zWPtr[index] = wordZ;
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carry &= !wordZ;
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}
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return;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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ui96:
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zWPtr[indexWordHi( 4 )] = ui96;
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}
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#endif
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