mirror of
https://github.com/urbit/shrub.git
synced 2024-12-18 15:55:00 +03:00
137 lines
4.7 KiB
C
137 lines
4.7 KiB
C
|
|
/*============================================================================
|
|
|
|
This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
|
|
Package, Release 3, by John R. Hauser.
|
|
|
|
Copyright 2011, 2012, 2013, 2014 The Regents of the University of California
|
|
(Regents). All Rights Reserved. Redistribution and use in source and binary
|
|
forms, with or without modification, are permitted provided that the following
|
|
conditions are met:
|
|
|
|
Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions, and the following two paragraphs of disclaimer.
|
|
Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions, and the following two paragraphs of disclaimer in the
|
|
documentation and/or other materials provided with the distribution. Neither
|
|
the name of the Regents nor the names of its contributors may be used to
|
|
endorse or promote products derived from this software without specific prior
|
|
written permission.
|
|
|
|
IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
|
|
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
|
|
OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
|
|
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
|
|
HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
|
|
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
|
|
|
|
=============================================================================*/
|
|
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include "platform.h"
|
|
#include "internals.h"
|
|
#include "specialize.h"
|
|
#include "softfloat.h"
|
|
|
|
float128_t
|
|
softfloat_subMagsF128(
|
|
uint_fast64_t uiA64,
|
|
uint_fast64_t uiA0,
|
|
uint_fast64_t uiB64,
|
|
uint_fast64_t uiB0,
|
|
bool signZ
|
|
)
|
|
{
|
|
int_fast32_t expA;
|
|
struct uint128 sigA;
|
|
int_fast32_t expB;
|
|
struct uint128 sigB, sigZ;
|
|
int_fast32_t expDiff, expZ;
|
|
struct uint128 uiZ;
|
|
union ui128_f128 uZ;
|
|
|
|
expA = expF128UI64( uiA64 );
|
|
sigA.v64 = fracF128UI64( uiA64 );
|
|
sigA.v0 = uiA0;
|
|
expB = expF128UI64( uiB64 );
|
|
sigB.v64 = fracF128UI64( uiB64 );
|
|
sigB.v0 = uiB0;
|
|
sigA = softfloat_shortShiftLeft128( sigA.v64, sigA.v0, 4 );
|
|
sigB = softfloat_shortShiftLeft128( sigB.v64, sigB.v0, 4 );
|
|
expDiff = expA - expB;
|
|
if ( 0 < expDiff ) goto expABigger;
|
|
if ( expDiff < 0 ) goto expBBigger;
|
|
if ( expA == 0x7FFF ) {
|
|
if ( sigA.v64 | sigA.v0 | sigB.v64 | sigB.v0 ) goto propagateNaN;
|
|
softfloat_raiseFlags( softfloat_flag_invalid );
|
|
uiZ.v64 = defaultNaNF128UI64;
|
|
uiZ.v0 = defaultNaNF128UI0;
|
|
goto uiZ;
|
|
}
|
|
expZ = expA;
|
|
if ( ! expZ ) expZ = 1;
|
|
if ( sigB.v64 < sigA.v64 ) goto aBigger;
|
|
if ( sigA.v64 < sigB.v64 ) goto bBigger;
|
|
if ( sigB.v0 < sigA.v0 ) goto aBigger;
|
|
if ( sigA.v0 < sigB.v0 ) goto bBigger;
|
|
uiZ.v64 =
|
|
packToF128UI64(
|
|
(softfloat_roundingMode == softfloat_round_min), 0, 0 );
|
|
uiZ.v0 = 0;
|
|
goto uiZ;
|
|
expBBigger:
|
|
if ( expB == 0x7FFF ) {
|
|
if ( sigB.v64 | sigB.v0 ) goto propagateNaN;
|
|
uiZ.v64 = packToF128UI64( signZ ^ 1, 0x7FFF, 0 );
|
|
uiZ.v0 = 0;
|
|
goto uiZ;
|
|
}
|
|
if ( expA ) {
|
|
sigA.v64 |= UINT64_C( 0x0010000000000000 );
|
|
} else {
|
|
++expDiff;
|
|
if ( ! expDiff ) goto newlyAlignedBBigger;
|
|
}
|
|
sigA = softfloat_shiftRightJam128( sigA.v64, sigA.v0, -expDiff );
|
|
newlyAlignedBBigger:
|
|
expZ = expB;
|
|
sigB.v64 |= UINT64_C( 0x0010000000000000 );
|
|
bBigger:
|
|
signZ ^= 1;
|
|
sigZ = softfloat_sub128( sigB.v64, sigB.v0, sigA.v64, sigA.v0 );
|
|
goto normRoundPack;
|
|
expABigger:
|
|
if ( expA == 0x7FFF ) {
|
|
if ( sigA.v64 | sigA.v0 ) goto propagateNaN;
|
|
uiZ.v64 = uiA64;
|
|
uiZ.v0 = uiA0;
|
|
goto uiZ;
|
|
}
|
|
if ( expB ) {
|
|
sigB.v64 |= UINT64_C( 0x0010000000000000 );
|
|
} else {
|
|
--expDiff;
|
|
if ( ! expDiff ) goto newlyAlignedABigger;
|
|
}
|
|
sigB = softfloat_shiftRightJam128( sigB.v64, sigB.v0, expDiff );
|
|
newlyAlignedABigger:
|
|
expZ = expA;
|
|
sigA.v64 |= UINT64_C( 0x0010000000000000 );
|
|
aBigger:
|
|
sigZ = softfloat_sub128( sigA.v64, sigA.v0, sigB.v64, sigB.v0 );
|
|
normRoundPack:
|
|
return softfloat_normRoundPackToF128( signZ, expZ - 5, sigZ.v64, sigZ.v0 );
|
|
propagateNaN:
|
|
uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 );
|
|
uiZ:
|
|
uZ.ui = uiZ;
|
|
return uZ.f;
|
|
|
|
}
|
|
|