114 lines
4.8 KiB
C
114 lines
4.8 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, 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"
|
||
|
|
|
||
|
|
float32_t
|
||
|
|
softfloat_roundPackToF32( bool sign, int_fast16_t exp, uint_fast32_t sig )
|
||
|
|
{
|
||
|
|
uint_fast8_t roundingMode;
|
||
|
|
bool roundNearEven;
|
||
|
|
uint_fast8_t roundIncrement, roundBits;
|
||
|
|
bool isTiny;
|
||
|
|
uint_fast32_t uiZ;
|
||
|
|
union ui32_f32 uZ;
|
||
|
|
|
||
|
|
/*------------------------------------------------------------------------
|
||
|
|
*------------------------------------------------------------------------*/
|
||
|
|
roundingMode = softfloat_roundingMode;
|
||
|
|
roundNearEven = (roundingMode == softfloat_round_near_even);
|
||
|
|
roundIncrement = 0x40;
|
||
|
|
if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
|
||
|
|
roundIncrement =
|
||
|
|
(roundingMode
|
||
|
|
== (sign ? softfloat_round_min : softfloat_round_max))
|
||
|
|
? 0x7F
|
||
|
|
: 0;
|
||
|
|
}
|
||
|
|
roundBits = sig & 0x7F;
|
||
|
|
/*------------------------------------------------------------------------
|
||
|
|
*------------------------------------------------------------------------*/
|
||
|
|
if ( 0xFD <= (unsigned int) exp ) {
|
||
|
|
if ( exp < 0 ) {
|
||
|
|
/*----------------------------------------------------------------
|
||
|
|
*----------------------------------------------------------------*/
|
||
|
|
isTiny =
|
||
|
|
(softfloat_detectTininess == softfloat_tininess_beforeRounding)
|
||
|
|
|| (exp < -1) || (sig + roundIncrement < 0x80000000);
|
||
|
|
sig = softfloat_shiftRightJam32( sig, -exp );
|
||
|
|
exp = 0;
|
||
|
|
roundBits = sig & 0x7F;
|
||
|
|
if ( isTiny && roundBits ) {
|
||
|
|
softfloat_raiseFlags( softfloat_flag_underflow );
|
||
|
|
}
|
||
|
|
} else if ( (0xFD < exp) || (0x80000000 <= sig + roundIncrement) ) {
|
||
|
|
/*----------------------------------------------------------------
|
||
|
|
*----------------------------------------------------------------*/
|
||
|
|
softfloat_raiseFlags(
|
||
|
|
softfloat_flag_overflow | softfloat_flag_inexact );
|
||
|
|
uiZ = packToF32UI( sign, 0xFF, 0 ) - ! roundIncrement;
|
||
|
|
goto uiZ;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
/*------------------------------------------------------------------------
|
||
|
|
*------------------------------------------------------------------------*/
|
||
|
|
sig = (sig + roundIncrement)>>7;
|
||
|
|
if ( roundBits ) {
|
||
|
|
softfloat_exceptionFlags |= softfloat_flag_inexact;
|
||
|
|
#ifdef SOFTFLOAT_ROUND_ODD
|
||
|
|
if ( roundingMode == softfloat_round_odd ) {
|
||
|
|
sig |= 1;
|
||
|
|
goto packReturn;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
sig &= ~(uint_fast32_t) (! (roundBits ^ 0x40) & roundNearEven);
|
||
|
|
if ( ! sig ) exp = 0;
|
||
|
|
/*------------------------------------------------------------------------
|
||
|
|
*------------------------------------------------------------------------*/
|
||
|
|
packReturn:
|
||
|
|
uiZ = packToF32UI( sign, exp, sig );
|
||
|
|
uiZ:
|
||
|
|
uZ.ui = uiZ;
|
||
|
|
return uZ.f;
|
||
|
|
|
||
|
|
}
|
||
|
|
|