204 lines
7.9 KiB
C
204 lines
7.9 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 The Regents of the University of California.
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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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extFloat80_t extF80_div( extFloat80_t a, extFloat80_t b )
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{
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union { struct extFloat80M s; extFloat80_t f; } uA;
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uint_fast16_t uiA64;
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uint_fast64_t uiA0;
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bool signA;
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int_fast32_t expA;
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uint_fast64_t sigA;
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union { struct extFloat80M s; extFloat80_t f; } uB;
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uint_fast16_t uiB64;
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uint_fast64_t uiB0;
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bool signB;
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int_fast32_t expB;
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uint_fast64_t sigB;
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bool signZ;
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struct exp32_sig64 normExpSig;
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int_fast32_t expZ;
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struct uint128 rem;
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uint_fast32_t recip32;
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uint_fast64_t sigZ;
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int ix;
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uint_fast64_t q64;
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uint_fast32_t q;
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struct uint128 term;
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uint_fast64_t sigZExtra;
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struct uint128 uiZ;
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uint_fast16_t uiZ64;
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uint_fast64_t uiZ0;
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union { struct extFloat80M s; extFloat80_t f; } uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA64 = uA.s.signExp;
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uiA0 = uA.s.signif;
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signA = signExtF80UI64( uiA64 );
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expA = expExtF80UI64( uiA64 );
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sigA = uiA0;
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uB.f = b;
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uiB64 = uB.s.signExp;
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uiB0 = uB.s.signif;
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signB = signExtF80UI64( uiB64 );
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expB = expExtF80UI64( uiB64 );
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sigB = uiB0;
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signZ = signA ^ signB;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( expA == 0x7FFF ) {
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if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
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if ( expB == 0x7FFF ) {
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if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
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goto invalid;
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}
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goto infinity;
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}
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if ( expB == 0x7FFF ) {
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if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
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goto zero;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ! expB ) expB = 1;
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if ( ! (sigB & UINT64_C( 0x8000000000000000 )) ) {
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if ( ! sigB ) {
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if ( ! sigA ) goto invalid;
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softfloat_raiseFlags( softfloat_flag_infinite );
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goto infinity;
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}
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normExpSig = softfloat_normSubnormalExtF80Sig( sigB );
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expB += normExpSig.exp;
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sigB = normExpSig.sig;
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}
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if ( ! expA ) expA = 1;
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if ( ! (sigA & UINT64_C( 0x8000000000000000 )) ) {
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if ( ! sigA ) goto zero;
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normExpSig = softfloat_normSubnormalExtF80Sig( sigA );
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expA += normExpSig.exp;
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sigA = normExpSig.sig;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = expA - expB + 0x3FFF;
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if ( sigA < sigB ) {
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--expZ;
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rem = softfloat_shortShiftLeft128( 0, sigA, 32 );
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} else {
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rem = softfloat_shortShiftLeft128( 0, sigA, 31 );
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}
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recip32 = softfloat_approxRecip32_1( sigB>>32 );
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sigZ = 0;
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ix = 2;
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for (;;) {
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q64 = (uint_fast64_t) (uint32_t) (rem.v64>>2) * recip32;
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q = (q64 + 0x80000000)>>32;
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--ix;
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if ( ix < 0 ) break;
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rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
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term = softfloat_mul64ByShifted32To128( sigB, q );
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rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
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if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
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--q;
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rem = softfloat_add128( rem.v64, rem.v0, sigB>>32, sigB<<32 );
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}
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sigZ = (sigZ<<29) + q;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ((q + 1) & 0x3FFFFF) < 2 ) {
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rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
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term = softfloat_mul64ByShifted32To128( sigB, q );
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rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
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term = softfloat_shortShiftLeft128( 0, sigB, 32 );
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if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
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--q;
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rem = softfloat_add128( rem.v64, rem.v0, term.v64, term.v0 );
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} else if ( softfloat_le128( term.v64, term.v0, rem.v64, rem.v0 ) ) {
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++q;
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rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
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}
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if ( rem.v64 | rem.v0 ) q |= 1;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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sigZ = (sigZ<<6) + (q>>23);
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sigZExtra = (uint64_t) ((uint_fast64_t) q<<41);
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return
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softfloat_roundPackToExtF80(
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signZ, expZ, sigZ, sigZExtra, extF80_roundingPrecision );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN:
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uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
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uiZ64 = uiZ.v64;
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uiZ0 = uiZ.v0;
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_raiseFlags( softfloat_flag_invalid );
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uiZ64 = defaultNaNExtF80UI64;
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uiZ0 = defaultNaNExtF80UI0;
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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infinity:
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uiZ64 = packToExtF80UI64( signZ, 0x7FFF );
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uiZ0 = UINT64_C( 0x8000000000000000 );
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goto uiZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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zero:
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uiZ64 = packToExtF80UI64( signZ, 0 );
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uiZ0 = 0;
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uiZ:
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uZ.s.signExp = uiZ64;
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uZ.s.signif = uiZ0;
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return uZ.f;
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}
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