Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
200 lines
7.8 KiB
C
200 lines
7.8 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 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"
|
|
|
|
float128_t f128_div( float128_t a, float128_t b )
|
|
{
|
|
union ui128_f128 uA;
|
|
uint_fast64_t uiA64, uiA0;
|
|
bool signA;
|
|
int_fast32_t expA;
|
|
struct uint128 sigA;
|
|
union ui128_f128 uB;
|
|
uint_fast64_t uiB64, uiB0;
|
|
bool signB;
|
|
int_fast32_t expB;
|
|
struct uint128 sigB;
|
|
bool signZ;
|
|
struct exp32_sig128 normExpSig;
|
|
int_fast32_t expZ;
|
|
struct uint128 rem;
|
|
uint_fast32_t recip32;
|
|
int ix;
|
|
uint_fast64_t q64;
|
|
uint_fast32_t q;
|
|
struct uint128 term;
|
|
uint_fast32_t qs[3];
|
|
uint_fast64_t sigZExtra;
|
|
struct uint128 sigZ, uiZ;
|
|
union ui128_f128 uZ;
|
|
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
uA.f = a;
|
|
uiA64 = uA.ui.v64;
|
|
uiA0 = uA.ui.v0;
|
|
signA = signF128UI64( uiA64 );
|
|
expA = expF128UI64( uiA64 );
|
|
sigA.v64 = fracF128UI64( uiA64 );
|
|
sigA.v0 = uiA0;
|
|
uB.f = b;
|
|
uiB64 = uB.ui.v64;
|
|
uiB0 = uB.ui.v0;
|
|
signB = signF128UI64( uiB64 );
|
|
expB = expF128UI64( uiB64 );
|
|
sigB.v64 = fracF128UI64( uiB64 );
|
|
sigB.v0 = uiB0;
|
|
signZ = signA ^ signB;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( expA == 0x7FFF ) {
|
|
if ( sigA.v64 | sigA.v0 ) goto propagateNaN;
|
|
if ( expB == 0x7FFF ) {
|
|
if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
|
|
goto invalid;
|
|
}
|
|
goto infinity;
|
|
}
|
|
if ( expB == 0x7FFF ) {
|
|
if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
|
|
goto zero;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( ! expB ) {
|
|
if ( ! (sigB.v64 | sigB.v0) ) {
|
|
if ( ! (expA | sigA.v64 | sigA.v0) ) goto invalid;
|
|
softfloat_raiseFlags( softfloat_flag_infinite );
|
|
goto infinity;
|
|
}
|
|
normExpSig = softfloat_normSubnormalF128Sig( sigB.v64, sigB.v0 );
|
|
expB = normExpSig.exp;
|
|
sigB = normExpSig.sig;
|
|
}
|
|
if ( ! expA ) {
|
|
if ( ! (sigA.v64 | sigA.v0) ) goto zero;
|
|
normExpSig = softfloat_normSubnormalF128Sig( sigA.v64, sigA.v0 );
|
|
expA = normExpSig.exp;
|
|
sigA = normExpSig.sig;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
expZ = expA - expB + 0x3FFE;
|
|
sigA.v64 |= UINT64_C( 0x0001000000000000 );
|
|
sigB.v64 |= UINT64_C( 0x0001000000000000 );
|
|
rem = sigA;
|
|
if ( softfloat_lt128( sigA.v64, sigA.v0, sigB.v64, sigB.v0 ) ) {
|
|
--expZ;
|
|
rem = softfloat_add128( sigA.v64, sigA.v0, sigA.v64, sigA.v0 );
|
|
}
|
|
recip32 = softfloat_approxRecip32_1( sigB.v64>>17 );
|
|
ix = 3;
|
|
for (;;) {
|
|
q64 = (uint_fast64_t) (uint32_t) (rem.v64>>19) * recip32;
|
|
q = (q64 + 0x80000000)>>32;
|
|
--ix;
|
|
if ( ix < 0 ) break;
|
|
rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
|
|
term = softfloat_mul128By32( sigB.v64, sigB.v0, q );
|
|
rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
|
|
if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
|
|
--q;
|
|
rem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
|
|
}
|
|
qs[ix] = q;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( ((q + 1) & 7) < 2 ) {
|
|
rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 );
|
|
term = softfloat_mul128By32( sigB.v64, sigB.v0, q );
|
|
rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 );
|
|
if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) {
|
|
--q;
|
|
rem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
|
|
} else if ( softfloat_le128( sigB.v64, sigB.v0, rem.v64, rem.v0 ) ) {
|
|
++q;
|
|
rem = softfloat_sub128( rem.v64, rem.v0, sigB.v64, sigB.v0 );
|
|
}
|
|
if ( rem.v64 | rem.v0 ) q |= 1;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
sigZExtra = (uint64_t) ((uint_fast64_t) q<<60);
|
|
term = softfloat_shortShiftLeft128( 0, qs[1], 54 );
|
|
sigZ =
|
|
softfloat_add128(
|
|
(uint_fast64_t) qs[2]<<19, ((uint_fast64_t) qs[0]<<25) + (q>>4),
|
|
term.v64, term.v0
|
|
);
|
|
return
|
|
softfloat_roundPackToF128( signZ, expZ, sigZ.v64, sigZ.v0, sigZExtra );
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
propagateNaN:
|
|
uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 );
|
|
goto uiZ;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
invalid:
|
|
softfloat_raiseFlags( softfloat_flag_invalid );
|
|
uiZ.v64 = defaultNaNF128UI64;
|
|
uiZ.v0 = defaultNaNF128UI0;
|
|
goto uiZ;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
infinity:
|
|
uiZ.v64 = packToF128UI64( signZ, 0x7FFF, 0 );
|
|
goto uiZ0;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
zero:
|
|
uiZ.v64 = packToF128UI64( signZ, 0, 0 );
|
|
uiZ0:
|
|
uiZ.v0 = 0;
|
|
uiZ:
|
|
uZ.ui = uiZ;
|
|
return uZ.f;
|
|
|
|
}
|
|
|