181 lines
7.3 KiB
C
181 lines
7.3 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, 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 extF80M_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr )
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{
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*zPtr = extF80_sqrt( *aPtr );
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}
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#else
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void extF80M_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr )
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{
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const struct extFloat80M *aSPtr;
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struct extFloat80M *zSPtr;
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uint_fast16_t uiA64, signUI64;
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int32_t expA;
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uint64_t rem64;
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int32_t expZ;
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uint32_t rem96[3], sig32A, recipSqrt32, sig32Z, q;
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uint64_t sig64Z, x64;
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uint32_t rem32, term[4], rem[4], extSigZ[3];
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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aSPtr = (const struct extFloat80M *) aPtr;
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zSPtr = (struct extFloat80M *) zPtr;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uiA64 = aSPtr->signExp;
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signUI64 = uiA64 & packToExtF80UI64( 1, 0 );
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expA = expExtF80UI64( uiA64 );
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rem64 = aSPtr->signif;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( expA == 0x7FFF ) {
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if ( rem64 & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
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softfloat_propagateNaNExtF80M( aSPtr, 0, zSPtr );
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return;
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}
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if ( signUI64 ) goto invalid;
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rem64 = UINT64_C( 0x8000000000000000 );
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goto copyA;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ! expA ) expA = 1;
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if ( ! (rem64 & UINT64_C( 0x8000000000000000 )) ) {
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if ( ! rem64 ) {
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uiA64 = signUI64;
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goto copyA;
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}
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expA += softfloat_normExtF80SigM( &rem64 );
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}
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if ( signUI64 ) goto invalid;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = ((expA - 0x3FFF)>>1) + 0x3FFF;
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expA &= 1;
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softfloat_shortShiftLeft64To96M( rem64, 30 - expA, rem96 );
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sig32A = rem64>>32;
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recipSqrt32 = softfloat_approxRecipSqrt32_1( expA, sig32A );
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sig32Z = ((uint64_t) sig32A * recipSqrt32)>>32;
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if ( expA ) sig32Z >>= 1;
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rem64 =
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((uint64_t) rem96[indexWord( 3, 2 )]<<32 | rem96[indexWord( 3, 1 )])
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- (uint64_t) sig32Z * sig32Z;
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rem96[indexWord( 3, 2 )] = rem64>>32;
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rem96[indexWord( 3, 1 )] = rem64;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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q = ((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32;
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sig64Z = ((uint64_t) sig32Z<<32) + ((uint64_t) q<<3);
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term[indexWord( 3, 2 )] = 0;
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/*------------------------------------------------------------------------
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| (Repeating this loop is a rare occurrence.)
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*------------------------------------------------------------------------*/
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for (;;) {
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x64 = ((uint64_t) sig32Z<<32) + sig64Z;
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term[indexWord( 3, 1 )] = x64>>32;
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term[indexWord( 3, 0 )] = x64;
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softfloat_remStep96MBy32(
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rem96, 29, term, q, &rem[indexMultiwordHi( 4, 3 )] );
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rem32 = rem[indexWord( 4, 3 )];
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if ( ! (rem32 & 0x80000000) ) break;
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--q;
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sig64Z -= 1<<3;
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}
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rem64 = (uint64_t) rem32<<32 | rem[indexWord( 4, 2 )];
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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q = (((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32) + 2;
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if ( rem64>>34 ) q += recipSqrt32;
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x64 = (uint64_t) q<<7;
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extSigZ[indexWord( 3, 0 )] = x64;
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x64 = (sig64Z<<1) + (x64>>32);
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extSigZ[indexWord( 3, 2 )] = x64>>32;
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extSigZ[indexWord( 3, 1 )] = x64;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( (q & 0xFFFFFF) <= 2 ) {
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q &= ~(uint32_t) 0xFFFF;
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extSigZ[indexWordLo( 3 )] = q<<7;
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x64 = sig64Z + (q>>27);
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term[indexWord( 4, 3 )] = 0;
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term[indexWord( 4, 2 )] = x64>>32;
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term[indexWord( 4, 1 )] = x64;
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term[indexWord( 4, 0 )] = q<<5;
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rem[indexWord( 4, 0 )] = 0;
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softfloat_remStep128MBy32( rem, 28, term, q, rem );
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q = rem[indexWordHi( 4 )];
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if ( q & 0x80000000 ) {
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softfloat_sub1X96M( extSigZ );
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} else {
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if ( q || rem[indexWord( 4, 1 )] || rem[indexWord( 4, 2 )] ) {
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extSigZ[indexWordLo( 3 )] |= 1;
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}
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}
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}
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softfloat_roundPackMToExtF80M(
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0, expZ, extSigZ, extF80_roundingPrecision, zSPtr );
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return;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_invalidExtF80M( zSPtr );
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return;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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copyA:
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zSPtr->signExp = uiA64;
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zSPtr->signif = rem64;
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}
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#endif
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