mirror of
https://github.com/urbit/shrub.git
synced 2024-12-24 03:14:30 +03:00
156 lines
5.7 KiB
C
156 lines
5.7 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"
|
||
|
|
||
|
extFloat80_t
|
||
|
softfloat_subMagsExtF80(
|
||
|
uint_fast16_t uiA64,
|
||
|
uint_fast64_t uiA0,
|
||
|
uint_fast16_t uiB64,
|
||
|
uint_fast64_t uiB0,
|
||
|
bool signZ
|
||
|
)
|
||
|
{
|
||
|
int_fast32_t expA;
|
||
|
uint_fast64_t sigA;
|
||
|
int_fast32_t expB;
|
||
|
uint_fast64_t sigB;
|
||
|
int_fast32_t expDiff;
|
||
|
uint_fast16_t uiZ64;
|
||
|
uint_fast64_t uiZ0;
|
||
|
int_fast32_t expZ;
|
||
|
uint_fast64_t sigExtra;
|
||
|
struct uint128 sig128, uiZ;
|
||
|
union { struct extFloat80M s; extFloat80_t f; } uZ;
|
||
|
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
expA = expExtF80UI64( uiA64 );
|
||
|
sigA = uiA0;
|
||
|
expB = expExtF80UI64( uiB64 );
|
||
|
sigB = uiB0;
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
expDiff = expA - expB;
|
||
|
if ( 0 < expDiff ) goto expABigger;
|
||
|
if ( expDiff < 0 ) goto expBBigger;
|
||
|
if ( expA == 0x7FFF ) {
|
||
|
if ( (sigA | sigB) & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) {
|
||
|
goto propagateNaN;
|
||
|
}
|
||
|
softfloat_raiseFlags( softfloat_flag_invalid );
|
||
|
uiZ64 = defaultNaNExtF80UI64;
|
||
|
uiZ0 = defaultNaNExtF80UI0;
|
||
|
goto uiZ;
|
||
|
}
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
expZ = expA;
|
||
|
if ( ! expZ ) expZ = 1;
|
||
|
sigExtra = 0;
|
||
|
if ( sigB < sigA ) goto aBigger;
|
||
|
if ( sigA < sigB ) goto bBigger;
|
||
|
uiZ64 =
|
||
|
packToExtF80UI64( (softfloat_roundingMode == softfloat_round_min), 0 );
|
||
|
uiZ0 = 0;
|
||
|
goto uiZ;
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
expBBigger:
|
||
|
if ( expB == 0x7FFF ) {
|
||
|
if ( sigB & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
|
||
|
uiZ64 = packToExtF80UI64( signZ ^ 1, 0x7FFF );
|
||
|
uiZ0 = UINT64_C( 0x8000000000000000 );
|
||
|
goto uiZ;
|
||
|
}
|
||
|
if ( ! expA ) {
|
||
|
++expDiff;
|
||
|
sigExtra = 0;
|
||
|
if ( ! expDiff ) goto newlyAlignedBBigger;
|
||
|
}
|
||
|
sig128 = softfloat_shiftRightJam128( sigA, 0, -expDiff );
|
||
|
sigA = sig128.v64;
|
||
|
sigExtra = sig128.v0;
|
||
|
newlyAlignedBBigger:
|
||
|
expZ = expB;
|
||
|
bBigger:
|
||
|
signZ ^= 1;
|
||
|
sig128 = softfloat_sub128( sigB, 0, sigA, sigExtra );
|
||
|
goto normRoundPack;
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
expABigger:
|
||
|
if ( expA == 0x7FFF ) {
|
||
|
if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) goto propagateNaN;
|
||
|
uiZ64 = uiA64;
|
||
|
uiZ0 = uiA0;
|
||
|
goto uiZ;
|
||
|
}
|
||
|
if ( ! expB ) {
|
||
|
--expDiff;
|
||
|
sigExtra = 0;
|
||
|
if ( ! expDiff ) goto newlyAlignedABigger;
|
||
|
}
|
||
|
sig128 = softfloat_shiftRightJam128( sigB, 0, expDiff );
|
||
|
sigB = sig128.v64;
|
||
|
sigExtra = sig128.v0;
|
||
|
newlyAlignedABigger:
|
||
|
expZ = expA;
|
||
|
aBigger:
|
||
|
sig128 = softfloat_sub128( sigA, 0, sigB, sigExtra );
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
normRoundPack:
|
||
|
return
|
||
|
softfloat_normRoundPackToExtF80(
|
||
|
signZ, expZ, sig128.v64, sig128.v0, extF80_roundingPrecision );
|
||
|
/*------------------------------------------------------------------------
|
||
|
*------------------------------------------------------------------------*/
|
||
|
propagateNaN:
|
||
|
uiZ = softfloat_propagateNaNExtF80UI( uiA64, uiA0, uiB64, uiB0 );
|
||
|
uiZ64 = uiZ.v64;
|
||
|
uiZ0 = uiZ.v0;
|
||
|
uiZ:
|
||
|
uZ.s.signExp = uiZ64;
|
||
|
uZ.s.signif = uiZ0;
|
||
|
return uZ.f;
|
||
|
|
||
|
}
|
||
|
|