Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
181 lines
7.3 KiB
C
181 lines
7.3 KiB
C
|
|
/*============================================================================
|
|
|
|
This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
|
|
Package, Release 3e, by John R. Hauser.
|
|
|
|
Copyright 2011, 2012, 2013, 2014, 2015, 2017 The Regents of the University of
|
|
California. All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are met:
|
|
|
|
1. Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions, and the following disclaimer.
|
|
|
|
2. Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions, and the following disclaimer in the documentation
|
|
and/or other materials provided with the distribution.
|
|
|
|
3. Neither the name of the University nor the names of its contributors may
|
|
be used to endorse or promote products derived from this software without
|
|
specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
|
|
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
|
|
DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
|
|
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
|
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
|
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
=============================================================================*/
|
|
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include "platform.h"
|
|
#include "internals.h"
|
|
#include "specialize.h"
|
|
#include "softfloat.h"
|
|
|
|
#ifdef SOFTFLOAT_FAST_INT64
|
|
|
|
void extF80M_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr )
|
|
{
|
|
|
|
*zPtr = extF80_sqrt( *aPtr );
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
void extF80M_sqrt( const extFloat80_t *aPtr, extFloat80_t *zPtr )
|
|
{
|
|
const struct extFloat80M *aSPtr;
|
|
struct extFloat80M *zSPtr;
|
|
uint_fast16_t uiA64, signUI64;
|
|
int32_t expA;
|
|
uint64_t rem64;
|
|
int32_t expZ;
|
|
uint32_t rem96[3], sig32A, recipSqrt32, sig32Z, q;
|
|
uint64_t sig64Z, x64;
|
|
uint32_t rem32, term[4], rem[4], extSigZ[3];
|
|
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
aSPtr = (const struct extFloat80M *) aPtr;
|
|
zSPtr = (struct extFloat80M *) zPtr;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
uiA64 = aSPtr->signExp;
|
|
signUI64 = uiA64 & packToExtF80UI64( 1, 0 );
|
|
expA = expExtF80UI64( uiA64 );
|
|
rem64 = aSPtr->signif;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( expA == 0x7FFF ) {
|
|
if ( rem64 & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
|
|
softfloat_propagateNaNExtF80M( aSPtr, 0, zSPtr );
|
|
return;
|
|
}
|
|
if ( signUI64 ) goto invalid;
|
|
rem64 = UINT64_C( 0x8000000000000000 );
|
|
goto copyA;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( ! expA ) expA = 1;
|
|
if ( ! (rem64 & UINT64_C( 0x8000000000000000 )) ) {
|
|
if ( ! rem64 ) {
|
|
uiA64 = signUI64;
|
|
goto copyA;
|
|
}
|
|
expA += softfloat_normExtF80SigM( &rem64 );
|
|
}
|
|
if ( signUI64 ) goto invalid;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
expZ = ((expA - 0x3FFF)>>1) + 0x3FFF;
|
|
expA &= 1;
|
|
softfloat_shortShiftLeft64To96M( rem64, 30 - expA, rem96 );
|
|
sig32A = rem64>>32;
|
|
recipSqrt32 = softfloat_approxRecipSqrt32_1( expA, sig32A );
|
|
sig32Z = ((uint64_t) sig32A * recipSqrt32)>>32;
|
|
if ( expA ) sig32Z >>= 1;
|
|
rem64 =
|
|
((uint64_t) rem96[indexWord( 3, 2 )]<<32 | rem96[indexWord( 3, 1 )])
|
|
- (uint64_t) sig32Z * sig32Z;
|
|
rem96[indexWord( 3, 2 )] = rem64>>32;
|
|
rem96[indexWord( 3, 1 )] = rem64;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
q = ((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32;
|
|
sig64Z = ((uint64_t) sig32Z<<32) + ((uint64_t) q<<3);
|
|
term[indexWord( 3, 2 )] = 0;
|
|
/*------------------------------------------------------------------------
|
|
| (Repeating this loop is a rare occurrence.)
|
|
*------------------------------------------------------------------------*/
|
|
for (;;) {
|
|
x64 = ((uint64_t) sig32Z<<32) + sig64Z;
|
|
term[indexWord( 3, 1 )] = x64>>32;
|
|
term[indexWord( 3, 0 )] = x64;
|
|
softfloat_remStep96MBy32(
|
|
rem96, 29, term, q, &rem[indexMultiwordHi( 4, 3 )] );
|
|
rem32 = rem[indexWord( 4, 3 )];
|
|
if ( ! (rem32 & 0x80000000) ) break;
|
|
--q;
|
|
sig64Z -= 1<<3;
|
|
}
|
|
rem64 = (uint64_t) rem32<<32 | rem[indexWord( 4, 2 )];
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
q = (((uint32_t) (rem64>>2) * (uint64_t) recipSqrt32)>>32) + 2;
|
|
if ( rem64>>34 ) q += recipSqrt32;
|
|
x64 = (uint64_t) q<<7;
|
|
extSigZ[indexWord( 3, 0 )] = x64;
|
|
x64 = (sig64Z<<1) + (x64>>32);
|
|
extSigZ[indexWord( 3, 2 )] = x64>>32;
|
|
extSigZ[indexWord( 3, 1 )] = x64;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( (q & 0xFFFFFF) <= 2 ) {
|
|
q &= ~(uint32_t) 0xFFFF;
|
|
extSigZ[indexWordLo( 3 )] = q<<7;
|
|
x64 = sig64Z + (q>>27);
|
|
term[indexWord( 4, 3 )] = 0;
|
|
term[indexWord( 4, 2 )] = x64>>32;
|
|
term[indexWord( 4, 1 )] = x64;
|
|
term[indexWord( 4, 0 )] = q<<5;
|
|
rem[indexWord( 4, 0 )] = 0;
|
|
softfloat_remStep128MBy32( rem, 28, term, q, rem );
|
|
q = rem[indexWordHi( 4 )];
|
|
if ( q & 0x80000000 ) {
|
|
softfloat_sub1X96M( extSigZ );
|
|
} else {
|
|
if ( q || rem[indexWord( 4, 1 )] || rem[indexWord( 4, 2 )] ) {
|
|
extSigZ[indexWordLo( 3 )] |= 1;
|
|
}
|
|
}
|
|
}
|
|
softfloat_roundPackMToExtF80M(
|
|
0, expZ, extSigZ, extF80_roundingPrecision, zSPtr );
|
|
return;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
invalid:
|
|
softfloat_invalidExtF80M( zSPtr );
|
|
return;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
copyA:
|
|
zSPtr->signExp = uiA64;
|
|
zSPtr->signif = rem64;
|
|
|
|
}
|
|
|
|
#endif
|
|
|