Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
183 lines
7.3 KiB
C
183 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 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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#ifdef SOFTFLOAT_FAST_INT64
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void
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f128M_rem( const float128_t *aPtr, const float128_t *bPtr, float128_t *zPtr )
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{
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*zPtr = f128_rem( *aPtr, *bPtr );
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}
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#else
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void
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f128M_rem( const float128_t *aPtr, const float128_t *bPtr, float128_t *zPtr )
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{
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const uint32_t *aWPtr, *bWPtr;
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uint32_t *zWPtr, uiA96;
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int32_t expA, expB;
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uint32_t x[4], rem1[5], *remPtr;
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bool signRem;
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int32_t expDiff;
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uint32_t q, recip32;
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uint64_t q64;
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uint32_t rem2[5], *altRemPtr, *newRemPtr, wordMeanRem;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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aWPtr = (const uint32_t *) aPtr;
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bWPtr = (const uint32_t *) bPtr;
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zWPtr = (uint32_t *) zPtr;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uiA96 = aWPtr[indexWordHi( 4 )];
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expA = expF128UI96( uiA96 );
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expB = expF128UI96( bWPtr[indexWordHi( 4 )] );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( (expA == 0x7FFF) || (expB == 0x7FFF) ) {
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if ( softfloat_tryPropagateNaNF128M( aWPtr, bWPtr, zWPtr ) ) return;
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if ( expA == 0x7FFF ) goto invalid;
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goto copyA;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( expA < expB - 1 ) goto copyA;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expB = softfloat_shiftNormSigF128M( bWPtr, 13, x );
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if ( expB == -128 ) goto invalid;
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remPtr = &rem1[indexMultiwordLo( 5, 4 )];
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expA = softfloat_shiftNormSigF128M( aWPtr, 13, remPtr );
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if ( expA == -128 ) goto copyA;
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signRem = signF128UI96( uiA96 );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expDiff = expA - expB;
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if ( expDiff < 1 ) {
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if ( expDiff < -1 ) goto copyA;
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if ( expDiff ) {
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--expB;
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softfloat_add128M( x, x, x );
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q = 0;
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} else {
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q = (softfloat_compare128M( x, remPtr ) <= 0);
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if ( q ) softfloat_sub128M( remPtr, x, remPtr );
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}
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} else {
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recip32 =
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softfloat_approxRecip32_1(
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((uint64_t) x[indexWord( 4, 3 )]<<32 | x[indexWord( 4, 2 )])
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>>30
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);
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expDiff -= 30;
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for (;;) {
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q64 = (uint64_t) remPtr[indexWordHi( 4 )] * recip32;
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if ( expDiff < 0 ) break;
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q = (q64 + 0x80000000)>>32;
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softfloat_remStep128MBy32( remPtr, 29, x, q, remPtr );
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if ( remPtr[indexWordHi( 4 )] & 0x80000000 ) {
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softfloat_add128M( remPtr, x, remPtr );
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}
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expDiff -= 29;
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}
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/*--------------------------------------------------------------------
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| (`expDiff' cannot be less than -29 here.)
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*--------------------------------------------------------------------*/
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q = (uint32_t) (q64>>32)>>(~expDiff & 31);
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softfloat_remStep128MBy32( remPtr, expDiff + 30, x, q, remPtr );
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if ( remPtr[indexWordHi( 4 )] & 0x80000000 ) {
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altRemPtr = &rem2[indexMultiwordLo( 5, 4 )];
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softfloat_add128M( remPtr, x, altRemPtr );
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goto selectRem;
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}
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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altRemPtr = &rem2[indexMultiwordLo( 5, 4 )];
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do {
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++q;
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newRemPtr = altRemPtr;
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softfloat_sub128M( remPtr, x, newRemPtr );
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altRemPtr = remPtr;
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remPtr = newRemPtr;
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} while ( ! (remPtr[indexWordHi( 4 )] & 0x80000000) );
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selectRem:
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softfloat_add128M( remPtr, altRemPtr, x );
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wordMeanRem = x[indexWordHi( 4 )];
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if (
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(wordMeanRem & 0x80000000)
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|| (! wordMeanRem && (q & 1) && ! x[indexWord( 4, 0 )]
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&& ! (x[indexWord( 4, 2 )] | x[indexWord( 4, 1 )]))
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) {
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remPtr = altRemPtr;
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}
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if ( remPtr[indexWordHi( 4 )] & 0x80000000 ) {
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signRem = ! signRem;
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softfloat_negX128M( remPtr );
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}
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remPtr -= indexMultiwordLo( 5, 4 );
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remPtr[indexWordHi( 5 )] = 0;
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softfloat_normRoundPackMToF128M( signRem, expB + 18, remPtr, zWPtr );
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return;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_invalidF128M( zWPtr );
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return;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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copyA:
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zWPtr[indexWordHi( 4 )] = uiA96;
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zWPtr[indexWord( 4, 2 )] = aWPtr[indexWord( 4, 2 )];
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zWPtr[indexWord( 4, 1 )] = aWPtr[indexWord( 4, 1 )];
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zWPtr[indexWord( 4, 0 )] = aWPtr[indexWord( 4, 0 )];
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}
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#endif
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