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174 lines
6.9 KiB
C
174 lines
6.9 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 3, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California (Regents). All Rights Reserved. Redistribution and use in source
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and binary forms, with or without modification, are permitted provided that
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the following conditions are met:
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Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer.
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Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer in the
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documentation and/or other materials provided with the distribution. Neither
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the name of the Regents nor the names of its contributors may be used to
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endorse or promote products derived from this software without specific prior
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written permission.
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IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
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OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
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BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
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HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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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 rem[4], sig32A, recipSqrt32, sig32Z, q;
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uint64_t sig64Z, x64;
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uint32_t term[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(
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rem64, 30 - expA, &rem[indexMultiwordHi( 4, 3 )] );
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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) rem[indexWord( 4, 3 )]<<32 | rem[indexWord( 4, 2 )])
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- (uint64_t) sig32Z * sig32Z;
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rem[indexWord( 4, 3 )] = rem64>>32;
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rem[indexWord( 4, 2 )] = 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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x64 = ((uint64_t) sig32Z<<32) + sig64Z;
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term[indexWord( 3, 2 )] = 0;
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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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&rem[indexMultiwordHi( 4, 3 )],
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29,
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term,
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q,
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&rem[indexMultiwordHi( 4, 3 )]
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);
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rem64 = (uint64_t) rem[indexWord( 4, 3 )]<<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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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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