mirror of
https://github.com/urbit/shrub.git
synced 2024-12-23 19:05:48 +03:00
148 lines
5.5 KiB
C
148 lines
5.5 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, 2015 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 "softfloat.h"
|
|
|
|
float128_t
|
|
softfloat_roundPackToF128(
|
|
bool sign,
|
|
int_fast32_t exp,
|
|
uint_fast64_t sig64,
|
|
uint_fast64_t sig0,
|
|
uint_fast64_t sigExtra
|
|
)
|
|
{
|
|
uint_fast8_t roundingMode;
|
|
bool roundNearEven, doIncrement, isTiny;
|
|
struct uint128_extra sig128Extra;
|
|
uint_fast64_t uiZ64, uiZ0;
|
|
struct uint128 sig128;
|
|
union ui128_f128 uZ;
|
|
|
|
roundingMode = softfloat_roundingMode;
|
|
roundNearEven = (roundingMode == softfloat_round_near_even);
|
|
doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra);
|
|
if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
|
|
doIncrement =
|
|
(roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
&& sigExtra;
|
|
}
|
|
if ( 0x7FFD <= (uint32_t) exp ) {
|
|
if ( exp < 0 ) {
|
|
isTiny =
|
|
(softfloat_detectTininess
|
|
== softfloat_tininess_beforeRounding)
|
|
|| (exp < -1)
|
|
|| ! doIncrement
|
|
|| softfloat_lt128(
|
|
sig64,
|
|
sig0,
|
|
UINT64_C( 0x0001FFFFFFFFFFFF ),
|
|
UINT64_C( 0xFFFFFFFFFFFFFFFF )
|
|
);
|
|
sig128Extra =
|
|
softfloat_shiftRightJam128Extra( sig64, sig0, sigExtra, -exp );
|
|
sig64 = sig128Extra.v.v64;
|
|
sig0 = sig128Extra.v.v0;
|
|
sigExtra = sig128Extra.extra;
|
|
exp = 0;
|
|
if ( isTiny && sigExtra ) {
|
|
softfloat_raiseFlags( softfloat_flag_underflow );
|
|
}
|
|
doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra);
|
|
if (
|
|
! roundNearEven
|
|
&& (roundingMode != softfloat_round_near_maxMag)
|
|
) {
|
|
doIncrement =
|
|
(roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
&& sigExtra;
|
|
}
|
|
} else if (
|
|
(0x7FFD < exp)
|
|
|| ((exp == 0x7FFD)
|
|
&& softfloat_eq128(
|
|
sig64,
|
|
sig0,
|
|
UINT64_C( 0x0001FFFFFFFFFFFF ),
|
|
UINT64_C( 0xFFFFFFFFFFFFFFFF )
|
|
)
|
|
&& doIncrement)
|
|
) {
|
|
softfloat_raiseFlags(
|
|
softfloat_flag_overflow | softfloat_flag_inexact );
|
|
if (
|
|
roundNearEven
|
|
|| (roundingMode == softfloat_round_near_maxMag)
|
|
|| (roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
) {
|
|
uiZ64 = packToF128UI64( sign, 0x7FFF, 0 );
|
|
uiZ0 = 0;
|
|
} else {
|
|
uiZ64 =
|
|
packToF128UI64(
|
|
sign, 0x7FFE, UINT64_C( 0x0000FFFFFFFFFFFF ) );
|
|
uiZ0 = UINT64_C( 0xFFFFFFFFFFFFFFFF );
|
|
}
|
|
goto uiZ;
|
|
}
|
|
}
|
|
if ( sigExtra ) softfloat_exceptionFlags |= softfloat_flag_inexact;
|
|
if ( doIncrement ) {
|
|
sig128 = softfloat_add128( sig64, sig0, 0, 1 );
|
|
sig64 = sig128.v64;
|
|
sig0 =
|
|
sig128.v0
|
|
& ~(uint64_t)
|
|
(! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF ))
|
|
& roundNearEven);
|
|
} else {
|
|
if ( ! (sig64 | sig0) ) exp = 0;
|
|
}
|
|
uiZ64 = packToF128UI64( sign, exp, sig64 );
|
|
uiZ0 = sig0;
|
|
uiZ:
|
|
uZ.ui.v64 = uiZ64;
|
|
uZ.ui.v0 = uiZ0;
|
|
return uZ.f;
|
|
|
|
}
|
|
|