Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
188 lines
6.8 KiB
C
188 lines
6.8 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_div( const float128_t *aPtr, const float128_t *bPtr, float128_t *zPtr )
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{
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*zPtr = f128_div( *aPtr, *bPtr );
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}
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#else
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void
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f128M_div( 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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bool signA;
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int32_t expA;
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uint32_t uiB96;
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bool signB;
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int32_t expB;
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bool signZ;
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uint32_t y[5], sigB[4];
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int32_t expZ;
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uint32_t recip32;
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int ix;
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uint64_t q64;
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uint32_t q, qs[3], uiZ96;
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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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signA = signF128UI96( uiA96 );
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expA = expF128UI96( uiA96 );
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uiB96 = bWPtr[indexWordHi( 4 )];
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signB = signF128UI96( uiB96 );
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expB = expF128UI96( uiB96 );
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signZ = signA ^ signB;
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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 ) {
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if ( expB == 0x7FFF ) goto invalid;
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goto infinity;
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}
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goto zero;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expA = softfloat_shiftNormSigF128M( aWPtr, 13, y );
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expB = softfloat_shiftNormSigF128M( bWPtr, 13, sigB );
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if ( expA == -128 ) {
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if ( expB == -128 ) goto invalid;
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goto zero;
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}
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if ( expB == -128 ) {
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softfloat_raiseFlags( softfloat_flag_infinite );
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goto infinity;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = expA - expB + 0x3FFE;
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if ( softfloat_compare128M( y, sigB ) < 0 ) {
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--expZ;
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softfloat_add128M( y, y, y );
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}
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recip32 =
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softfloat_approxRecip32_1(
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((uint64_t) sigB[indexWord( 4, 3 )]<<32 | sigB[indexWord( 4, 2 )])
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>>30
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);
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ix = 3;
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for (;;) {
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q64 = (uint64_t) y[indexWordHi( 4 )] * 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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softfloat_remStep128MBy32( y, 29, sigB, q, y );
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if ( y[indexWordHi( 4 )] & 0x80000000 ) {
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--q;
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softfloat_add128M( y, sigB, y );
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}
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qs[ix] = q;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ((q + 1) & 7) < 2 ) {
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softfloat_remStep128MBy32( y, 29, sigB, q, y );
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if ( y[indexWordHi( 4 )] & 0x80000000 ) {
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--q;
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softfloat_add128M( y, sigB, y );
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} else if ( softfloat_compare128M( sigB, y ) <= 0 ) {
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++q;
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softfloat_sub128M( y, sigB, y );
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}
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if (
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y[indexWordLo( 4 )] || y[indexWord( 4, 1 )]
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|| (y[indexWord( 4, 2 )] | y[indexWord( 4, 3 )])
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) {
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q |= 1;
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}
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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q64 = (uint64_t) q<<28;
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y[indexWord( 5, 0 )] = q64;
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q64 = ((uint64_t) qs[0]<<25) + (q64>>32);
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y[indexWord( 5, 1 )] = q64;
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q64 = ((uint64_t) qs[1]<<22) + (q64>>32);
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y[indexWord( 5, 2 )] = q64;
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q64 = ((uint64_t) qs[2]<<19) + (q64>>32);
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y[indexWord( 5, 3 )] = q64;
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y[indexWord( 5, 4 )] = q64>>32;
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softfloat_roundPackMToF128M( signZ, expZ, y, 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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infinity:
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uiZ96 = packToF128UI96( signZ, 0x7FFF, 0 );
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goto uiZ96;
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zero:
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uiZ96 = packToF128UI96( signZ, 0, 0 );
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uiZ96:
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zWPtr[indexWordHi( 4 )] = uiZ96;
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zWPtr[indexWord( 4, 2 )] = 0;
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zWPtr[indexWord( 4, 1 )] = 0;
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zWPtr[indexWord( 4, 0 )] = 0;
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}
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#endif
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