257 lines
9.9 KiB
C
257 lines
9.9 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 "softfloat.h"
|
|
|
|
void
|
|
softfloat_roundPackMToExtF80M(
|
|
bool sign,
|
|
int32_t exp,
|
|
uint32_t *extSigPtr,
|
|
uint_fast8_t roundingPrecision,
|
|
struct extFloat80M *zSPtr
|
|
)
|
|
{
|
|
uint_fast8_t roundingMode;
|
|
bool roundNearEven;
|
|
uint64_t sig, roundIncrement, roundMask, roundBits;
|
|
bool isTiny;
|
|
uint32_t sigExtra;
|
|
bool doIncrement;
|
|
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
roundingMode = softfloat_roundingMode;
|
|
roundNearEven = (roundingMode == softfloat_round_near_even);
|
|
sig =
|
|
(uint64_t) extSigPtr[indexWord( 3, 2 )]<<32
|
|
| extSigPtr[indexWord( 3, 1 )];
|
|
if ( roundingPrecision == 80 ) goto precision80;
|
|
if ( roundingPrecision == 64 ) {
|
|
roundIncrement = UINT64_C( 0x0000000000000400 );
|
|
roundMask = UINT64_C( 0x00000000000007FF );
|
|
} else if ( roundingPrecision == 32 ) {
|
|
roundIncrement = UINT64_C( 0x0000008000000000 );
|
|
roundMask = UINT64_C( 0x000000FFFFFFFFFF );
|
|
} else {
|
|
goto precision80;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( extSigPtr[indexWordLo( 3 )] ) sig |= 1;
|
|
if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
|
|
roundIncrement =
|
|
(roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
? roundMask
|
|
: 0;
|
|
}
|
|
roundBits = sig & roundMask;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( 0x7FFD <= (uint32_t) (exp - 1) ) {
|
|
if ( exp <= 0 ) {
|
|
/*----------------------------------------------------------------
|
|
*----------------------------------------------------------------*/
|
|
isTiny =
|
|
(softfloat_detectTininess
|
|
== softfloat_tininess_beforeRounding)
|
|
|| (exp < 0)
|
|
|| (sig <= (uint64_t) (sig + roundIncrement));
|
|
sig = softfloat_shiftRightJam64( sig, 1 - exp );
|
|
roundBits = sig & roundMask;
|
|
if ( roundBits ) {
|
|
if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow );
|
|
softfloat_exceptionFlags |= softfloat_flag_inexact;
|
|
#ifdef SOFTFLOAT_ROUND_ODD
|
|
if ( roundingMode == softfloat_round_odd ) {
|
|
sig |= roundMask + 1;
|
|
}
|
|
#endif
|
|
}
|
|
sig += roundIncrement;
|
|
exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0);
|
|
roundIncrement = roundMask + 1;
|
|
if ( roundNearEven && (roundBits<<1 == roundIncrement) ) {
|
|
roundMask |= roundIncrement;
|
|
}
|
|
sig &= ~roundMask;
|
|
goto packReturn;
|
|
}
|
|
if (
|
|
(0x7FFE < exp)
|
|
|| ((exp == 0x7FFE) && ((uint64_t) (sig + roundIncrement) < sig))
|
|
) {
|
|
goto overflow;
|
|
}
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( roundBits ) {
|
|
softfloat_exceptionFlags |= softfloat_flag_inexact;
|
|
#ifdef SOFTFLOAT_ROUND_ODD
|
|
if ( roundingMode == softfloat_round_odd ) {
|
|
sig = (sig & ~roundMask) | (roundMask + 1);
|
|
goto packReturn;
|
|
}
|
|
#endif
|
|
}
|
|
sig += roundIncrement;
|
|
if ( sig < roundIncrement ) {
|
|
++exp;
|
|
sig = UINT64_C( 0x8000000000000000 );
|
|
}
|
|
roundIncrement = roundMask + 1;
|
|
if ( roundNearEven && (roundBits<<1 == roundIncrement) ) {
|
|
roundMask |= roundIncrement;
|
|
}
|
|
sig &= ~roundMask;
|
|
goto packReturn;
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
precision80:
|
|
sigExtra = extSigPtr[indexWordLo( 3 )];
|
|
doIncrement = (0x80000000 <= sigExtra);
|
|
if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
|
|
doIncrement =
|
|
(roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
&& sigExtra;
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( 0x7FFD <= (uint32_t) (exp - 1) ) {
|
|
if ( exp <= 0 ) {
|
|
/*----------------------------------------------------------------
|
|
*----------------------------------------------------------------*/
|
|
isTiny =
|
|
(softfloat_detectTininess
|
|
== softfloat_tininess_beforeRounding)
|
|
|| (exp < 0)
|
|
|| ! doIncrement
|
|
|| (sig < UINT64_C( 0xFFFFFFFFFFFFFFFF ));
|
|
softfloat_shiftRightJam96M( extSigPtr, 1 - exp, extSigPtr );
|
|
exp = 0;
|
|
sig =
|
|
(uint64_t) extSigPtr[indexWord( 3, 2 )]<<32
|
|
| extSigPtr[indexWord( 3, 1 )];
|
|
sigExtra = extSigPtr[indexWordLo( 3 )];
|
|
if ( sigExtra ) {
|
|
if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow );
|
|
softfloat_exceptionFlags |= softfloat_flag_inexact;
|
|
#ifdef SOFTFLOAT_ROUND_ODD
|
|
if ( roundingMode == softfloat_round_odd ) {
|
|
sig |= 1;
|
|
goto packReturn;
|
|
}
|
|
#endif
|
|
}
|
|
doIncrement = (0x80000000 <= sigExtra);
|
|
if (
|
|
! roundNearEven
|
|
&& (roundingMode != softfloat_round_near_maxMag)
|
|
) {
|
|
doIncrement =
|
|
(roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
&& sigExtra;
|
|
}
|
|
if ( doIncrement ) {
|
|
++sig;
|
|
sig &= ~(uint64_t) (! (sigExtra & 0x7FFFFFFF) & roundNearEven);
|
|
exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0);
|
|
}
|
|
goto packReturn;
|
|
}
|
|
if (
|
|
(0x7FFE < exp)
|
|
|| ((exp == 0x7FFE) && (sig == UINT64_C( 0xFFFFFFFFFFFFFFFF ))
|
|
&& doIncrement)
|
|
) {
|
|
/*----------------------------------------------------------------
|
|
*----------------------------------------------------------------*/
|
|
roundMask = 0;
|
|
overflow:
|
|
softfloat_raiseFlags(
|
|
softfloat_flag_overflow | softfloat_flag_inexact );
|
|
if (
|
|
roundNearEven
|
|
|| (roundingMode == softfloat_round_near_maxMag)
|
|
|| (roundingMode
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
|
) {
|
|
exp = 0x7FFF;
|
|
sig = UINT64_C( 0x8000000000000000 );
|
|
} else {
|
|
exp = 0x7FFE;
|
|
sig = ~roundMask;
|
|
}
|
|
goto packReturn;
|
|
}
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
if ( sigExtra ) {
|
|
softfloat_exceptionFlags |= softfloat_flag_inexact;
|
|
#ifdef SOFTFLOAT_ROUND_ODD
|
|
if ( roundingMode == softfloat_round_odd ) {
|
|
sig |= 1;
|
|
goto packReturn;
|
|
}
|
|
#endif
|
|
}
|
|
if ( doIncrement ) {
|
|
++sig;
|
|
if ( ! sig ) {
|
|
++exp;
|
|
sig = UINT64_C( 0x8000000000000000 );
|
|
} else {
|
|
sig &= ~(uint64_t) (! (sigExtra & 0x7FFFFFFF) & roundNearEven);
|
|
}
|
|
}
|
|
/*------------------------------------------------------------------------
|
|
*------------------------------------------------------------------------*/
|
|
packReturn:
|
|
zSPtr->signExp = packToExtF80UI64( sign, exp );
|
|
zSPtr->signif = sig;
|
|
|
|
}
|
|
|