225 lines
8.3 KiB
C
225 lines
8.3 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, 2015, 2016 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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float32_t
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softfloat_mulAddF32(
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uint_fast32_t uiA, uint_fast32_t uiB, uint_fast32_t uiC, uint_fast8_t op )
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{
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bool signA;
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int_fast16_t expA;
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uint_fast32_t sigA;
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bool signB;
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int_fast16_t expB;
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uint_fast32_t sigB;
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bool signC;
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int_fast16_t expC;
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uint_fast32_t sigC;
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bool signProd;
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uint_fast32_t magBits, uiZ;
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struct exp16_sig32 normExpSig;
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int_fast16_t expProd;
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uint_fast64_t sigProd;
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bool signZ;
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int_fast16_t expZ;
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uint_fast32_t sigZ;
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int_fast16_t expDiff;
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uint_fast64_t sig64Z, sig64C;
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int_fast8_t shiftDist;
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union ui32_f32 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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signA = signF32UI( uiA );
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expA = expF32UI( uiA );
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sigA = fracF32UI( uiA );
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signB = signF32UI( uiB );
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expB = expF32UI( uiB );
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sigB = fracF32UI( uiB );
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signC = signF32UI( uiC ) ^ (op == softfloat_mulAdd_subC);
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expC = expF32UI( uiC );
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sigC = fracF32UI( uiC );
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signProd = signA ^ signB ^ (op == softfloat_mulAdd_subProd);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( expA == 0xFF ) {
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if ( sigA || ((expB == 0xFF) && sigB) ) goto propagateNaN_ABC;
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magBits = expB | sigB;
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goto infProdArg;
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}
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if ( expB == 0xFF ) {
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if ( sigB ) goto propagateNaN_ABC;
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magBits = expA | sigA;
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goto infProdArg;
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}
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if ( expC == 0xFF ) {
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if ( sigC ) {
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uiZ = 0;
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goto propagateNaN_ZC;
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}
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uiZ = uiC;
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ! expA ) {
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if ( ! sigA ) goto zeroProd;
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normExpSig = softfloat_normSubnormalF32Sig( sigA );
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expA = normExpSig.exp;
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sigA = normExpSig.sig;
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}
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if ( ! expB ) {
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if ( ! sigB ) goto zeroProd;
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normExpSig = softfloat_normSubnormalF32Sig( sigB );
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expB = normExpSig.exp;
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sigB = normExpSig.sig;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expProd = expA + expB - 0x7E;
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sigA = (sigA | 0x00800000)<<7;
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sigB = (sigB | 0x00800000)<<7;
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sigProd = (uint_fast64_t) sigA * sigB;
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if ( sigProd < UINT64_C( 0x2000000000000000 ) ) {
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--expProd;
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sigProd <<= 1;
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}
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signZ = signProd;
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if ( ! expC ) {
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if ( ! sigC ) {
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expZ = expProd - 1;
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sigZ = softfloat_shortShiftRightJam64( sigProd, 31 );
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goto roundPack;
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}
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normExpSig = softfloat_normSubnormalF32Sig( sigC );
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expC = normExpSig.exp;
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sigC = normExpSig.sig;
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}
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sigC = (sigC | 0x00800000)<<6;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expDiff = expProd - expC;
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if ( signProd == signC ) {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( expDiff <= 0 ) {
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expZ = expC;
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sigZ = sigC + softfloat_shiftRightJam64( sigProd, 32 - expDiff );
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} else {
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expZ = expProd;
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sig64Z =
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sigProd
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+ softfloat_shiftRightJam64(
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(uint_fast64_t) sigC<<32, expDiff );
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sigZ = softfloat_shortShiftRightJam64( sig64Z, 32 );
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}
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if ( sigZ < 0x40000000 ) {
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--expZ;
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sigZ <<= 1;
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}
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} else {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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sig64C = (uint_fast64_t) sigC<<32;
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if ( expDiff < 0 ) {
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signZ = signC;
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expZ = expC;
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sig64Z = sig64C - softfloat_shiftRightJam64( sigProd, -expDiff );
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} else if ( ! expDiff ) {
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expZ = expProd;
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sig64Z = sigProd - sig64C;
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if ( ! sig64Z ) goto completeCancellation;
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if ( sig64Z & UINT64_C( 0x8000000000000000 ) ) {
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signZ = ! signZ;
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sig64Z = -sig64Z;
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}
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} else {
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expZ = expProd;
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sig64Z = sigProd - softfloat_shiftRightJam64( sig64C, expDiff );
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}
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shiftDist = softfloat_countLeadingZeros64( sig64Z ) - 1;
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expZ -= shiftDist;
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shiftDist -= 32;
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if ( shiftDist < 0 ) {
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sigZ = softfloat_shortShiftRightJam64( sig64Z, -shiftDist );
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} else {
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sigZ = (uint_fast32_t) sig64Z<<shiftDist;
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}
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}
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roundPack:
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return softfloat_roundPackToF32( signZ, expZ, sigZ );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN_ABC:
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uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
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goto propagateNaN_ZC;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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infProdArg:
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if ( magBits ) {
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uiZ = packToF32UI( signProd, 0xFF, 0 );
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if ( expC != 0xFF ) goto uiZ;
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if ( sigC ) goto propagateNaN_ZC;
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if ( signProd == signC ) goto uiZ;
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}
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softfloat_raiseFlags( softfloat_flag_invalid );
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uiZ = defaultNaNF32UI;
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propagateNaN_ZC:
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uiZ = softfloat_propagateNaNF32UI( uiZ, uiC );
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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zeroProd:
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uiZ = uiC;
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if ( ! (expC | sigC) && (signProd != signC) ) {
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completeCancellation:
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uiZ =
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packToF32UI(
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(softfloat_roundingMode == softfloat_round_min), 0, 0 );
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}
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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