Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
351 lines
14 KiB
C
351 lines
14 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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float128_t
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softfloat_mulAddF128(
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uint_fast64_t uiA64,
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uint_fast64_t uiA0,
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uint_fast64_t uiB64,
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uint_fast64_t uiB0,
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uint_fast64_t uiC64,
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uint_fast64_t uiC0,
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uint_fast8_t op
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)
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{
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bool signA;
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int_fast32_t expA;
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struct uint128 sigA;
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bool signB;
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int_fast32_t expB;
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struct uint128 sigB;
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bool signC;
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int_fast32_t expC;
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struct uint128 sigC;
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bool signZ;
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uint_fast64_t magBits;
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struct uint128 uiZ;
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struct exp32_sig128 normExpSig;
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int_fast32_t expZ;
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uint64_t sig256Z[4];
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struct uint128 sigZ;
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int_fast32_t shiftDist, expDiff;
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struct uint128 x128;
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uint64_t sig256C[4];
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static uint64_t zero256[4] = INIT_UINTM4( 0, 0, 0, 0 );
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uint_fast64_t sigZExtra, sig256Z0;
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union ui128_f128 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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signA = signF128UI64( uiA64 );
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expA = expF128UI64( uiA64 );
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sigA.v64 = fracF128UI64( uiA64 );
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sigA.v0 = uiA0;
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signB = signF128UI64( uiB64 );
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expB = expF128UI64( uiB64 );
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sigB.v64 = fracF128UI64( uiB64 );
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sigB.v0 = uiB0;
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signC = signF128UI64( uiC64 ) ^ (op == softfloat_mulAdd_subC);
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expC = expF128UI64( uiC64 );
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sigC.v64 = fracF128UI64( uiC64 );
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sigC.v0 = uiC0;
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signZ = signA ^ signB ^ (op == softfloat_mulAdd_subProd);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( expA == 0x7FFF ) {
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if (
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(sigA.v64 | sigA.v0) || ((expB == 0x7FFF) && (sigB.v64 | sigB.v0))
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) {
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goto propagateNaN_ABC;
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}
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magBits = expB | sigB.v64 | sigB.v0;
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goto infProdArg;
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}
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if ( expB == 0x7FFF ) {
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if ( sigB.v64 | sigB.v0 ) goto propagateNaN_ABC;
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magBits = expA | sigA.v64 | sigA.v0;
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goto infProdArg;
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}
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if ( expC == 0x7FFF ) {
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if ( sigC.v64 | sigC.v0 ) {
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uiZ.v64 = 0;
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uiZ.v0 = 0;
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goto propagateNaN_ZC;
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}
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uiZ.v64 = uiC64;
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uiZ.v0 = uiC0;
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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.v64 | sigA.v0) ) goto zeroProd;
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normExpSig = softfloat_normSubnormalF128Sig( sigA.v64, sigA.v0 );
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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.v64 | sigB.v0) ) goto zeroProd;
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normExpSig = softfloat_normSubnormalF128Sig( sigB.v64, sigB.v0 );
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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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expZ = expA + expB - 0x3FFE;
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sigA.v64 |= UINT64_C( 0x0001000000000000 );
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sigB.v64 |= UINT64_C( 0x0001000000000000 );
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sigA = softfloat_shortShiftLeft128( sigA.v64, sigA.v0, 8 );
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sigB = softfloat_shortShiftLeft128( sigB.v64, sigB.v0, 15 );
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softfloat_mul128To256M( sigA.v64, sigA.v0, sigB.v64, sigB.v0, sig256Z );
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sigZ.v64 = sig256Z[indexWord( 4, 3 )];
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sigZ.v0 = sig256Z[indexWord( 4, 2 )];
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shiftDist = 0;
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if ( ! (sigZ.v64 & UINT64_C( 0x0100000000000000 )) ) {
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--expZ;
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shiftDist = -1;
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}
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if ( ! expC ) {
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if ( ! (sigC.v64 | sigC.v0) ) {
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shiftDist += 8;
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goto sigZ;
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}
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normExpSig = softfloat_normSubnormalF128Sig( sigC.v64, sigC.v0 );
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expC = normExpSig.exp;
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sigC = normExpSig.sig;
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}
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sigC.v64 |= UINT64_C( 0x0001000000000000 );
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sigC = softfloat_shortShiftLeft128( sigC.v64, sigC.v0, 8 );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expDiff = expZ - expC;
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if ( expDiff < 0 ) {
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expZ = expC;
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if ( (signZ == signC) || (expDiff < -1) ) {
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shiftDist -= expDiff;
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if ( shiftDist ) {
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sigZ =
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softfloat_shiftRightJam128( sigZ.v64, sigZ.v0, shiftDist );
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}
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} else {
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if ( ! shiftDist ) {
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x128 =
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softfloat_shortShiftRight128(
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sig256Z[indexWord( 4, 1 )], sig256Z[indexWord( 4, 0 )],
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1
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);
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sig256Z[indexWord( 4, 1 )] = (sigZ.v0<<63) | x128.v64;
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sig256Z[indexWord( 4, 0 )] = x128.v0;
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sigZ = softfloat_shortShiftRight128( sigZ.v64, sigZ.v0, 1 );
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sig256Z[indexWord( 4, 3 )] = sigZ.v64;
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sig256Z[indexWord( 4, 2 )] = sigZ.v0;
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}
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}
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} else {
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if ( shiftDist ) softfloat_add256M( sig256Z, sig256Z, sig256Z );
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if ( ! expDiff ) {
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sigZ.v64 = sig256Z[indexWord( 4, 3 )];
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sigZ.v0 = sig256Z[indexWord( 4, 2 )];
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} else {
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sig256C[indexWord( 4, 3 )] = sigC.v64;
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sig256C[indexWord( 4, 2 )] = sigC.v0;
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sig256C[indexWord( 4, 1 )] = 0;
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sig256C[indexWord( 4, 0 )] = 0;
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softfloat_shiftRightJam256M( sig256C, expDiff, sig256C );
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}
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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shiftDist = 8;
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if ( signZ == signC ) {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( expDiff <= 0 ) {
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sigZ = softfloat_add128( sigC.v64, sigC.v0, sigZ.v64, sigZ.v0 );
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} else {
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softfloat_add256M( sig256Z, sig256C, sig256Z );
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sigZ.v64 = sig256Z[indexWord( 4, 3 )];
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sigZ.v0 = sig256Z[indexWord( 4, 2 )];
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}
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if ( sigZ.v64 & UINT64_C( 0x0200000000000000 ) ) {
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++expZ;
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shiftDist = 9;
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}
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} else {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( expDiff < 0 ) {
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signZ = signC;
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if ( expDiff < -1 ) {
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sigZ =
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softfloat_sub128( sigC.v64, sigC.v0, sigZ.v64, sigZ.v0 );
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sigZExtra =
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sig256Z[indexWord( 4, 1 )] | sig256Z[indexWord( 4, 0 )];
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if ( sigZExtra ) {
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sigZ = softfloat_sub128( sigZ.v64, sigZ.v0, 0, 1 );
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}
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if ( ! (sigZ.v64 & UINT64_C( 0x0100000000000000 )) ) {
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--expZ;
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shiftDist = 7;
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}
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goto shiftRightRoundPack;
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} else {
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sig256C[indexWord( 4, 3 )] = sigC.v64;
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sig256C[indexWord( 4, 2 )] = sigC.v0;
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sig256C[indexWord( 4, 1 )] = 0;
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sig256C[indexWord( 4, 0 )] = 0;
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softfloat_sub256M( sig256C, sig256Z, sig256Z );
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}
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} else if ( ! expDiff ) {
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sigZ = softfloat_sub128( sigZ.v64, sigZ.v0, sigC.v64, sigC.v0 );
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if (
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! (sigZ.v64 | sigZ.v0) && ! sig256Z[indexWord( 4, 1 )]
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&& ! sig256Z[indexWord( 4, 0 )]
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) {
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goto completeCancellation;
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}
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sig256Z[indexWord( 4, 3 )] = sigZ.v64;
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sig256Z[indexWord( 4, 2 )] = sigZ.v0;
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if ( sigZ.v64 & UINT64_C( 0x8000000000000000 ) ) {
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signZ = ! signZ;
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softfloat_sub256M( zero256, sig256Z, sig256Z );
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}
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} else {
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softfloat_sub256M( sig256Z, sig256C, sig256Z );
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if ( 1 < expDiff ) {
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sigZ.v64 = sig256Z[indexWord( 4, 3 )];
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sigZ.v0 = sig256Z[indexWord( 4, 2 )];
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if ( ! (sigZ.v64 & UINT64_C( 0x0100000000000000 )) ) {
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--expZ;
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shiftDist = 7;
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}
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goto sigZ;
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}
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}
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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sigZ.v64 = sig256Z[indexWord( 4, 3 )];
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sigZ.v0 = sig256Z[indexWord( 4, 2 )];
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sigZExtra = sig256Z[indexWord( 4, 1 )];
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sig256Z0 = sig256Z[indexWord( 4, 0 )];
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if ( sigZ.v64 ) {
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if ( sig256Z0 ) sigZExtra |= 1;
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} else {
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expZ -= 64;
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sigZ.v64 = sigZ.v0;
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sigZ.v0 = sigZExtra;
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sigZExtra = sig256Z0;
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if ( ! sigZ.v64 ) {
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expZ -= 64;
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sigZ.v64 = sigZ.v0;
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sigZ.v0 = sigZExtra;
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sigZExtra = 0;
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if ( ! sigZ.v64 ) {
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expZ -= 64;
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sigZ.v64 = sigZ.v0;
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sigZ.v0 = 0;
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}
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}
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}
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shiftDist = softfloat_countLeadingZeros64( sigZ.v64 );
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expZ += 7 - shiftDist;
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shiftDist = 15 - shiftDist;
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if ( 0 < shiftDist ) goto shiftRightRoundPack;
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if ( shiftDist ) {
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shiftDist = -shiftDist;
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sigZ = softfloat_shortShiftLeft128( sigZ.v64, sigZ.v0, shiftDist );
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x128 = softfloat_shortShiftLeft128( 0, sigZExtra, shiftDist );
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sigZ.v0 |= x128.v64;
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sigZExtra = x128.v0;
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}
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goto roundPack;
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}
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sigZ:
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sigZExtra = sig256Z[indexWord( 4, 1 )] | sig256Z[indexWord( 4, 0 )];
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shiftRightRoundPack:
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sigZExtra = (uint64_t) (sigZ.v0<<(64 - shiftDist)) | (sigZExtra != 0);
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sigZ = softfloat_shortShiftRight128( sigZ.v64, sigZ.v0, shiftDist );
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roundPack:
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return
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softfloat_roundPackToF128(
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signZ, expZ - 1, sigZ.v64, sigZ.v0, sigZExtra );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN_ABC:
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uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 );
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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.v64 = packToF128UI64( signZ, 0x7FFF, 0 );
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uiZ.v0 = 0;
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if ( expC != 0x7FFF ) goto uiZ;
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if ( sigC.v64 | sigC.v0 ) goto propagateNaN_ZC;
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if ( signZ == signC ) goto uiZ;
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}
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softfloat_raiseFlags( softfloat_flag_invalid );
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uiZ.v64 = defaultNaNF128UI64;
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uiZ.v0 = defaultNaNF128UI0;
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propagateNaN_ZC:
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uiZ = softfloat_propagateNaNF128UI( uiZ.v64, uiZ.v0, uiC64, uiC0 );
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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zeroProd:
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uiZ.v64 = uiC64;
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uiZ.v0 = uiC0;
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if ( ! (expC | sigC.v64 | sigC.v0) && (signZ != signC) ) {
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completeCancellation:
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uiZ.v64 =
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packToF128UI64(
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(softfloat_roundingMode == softfloat_round_min), 0, 0 );
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uiZ.v0 = 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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