mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
c5033d7803
It looks glibc's pow() assumes an unary '-' operation for any number
(including NaNs) always inverts its sign bit (though IEEE754 does not
specify the sign bit for NaNs). This patch make the kernel math-emu
emulates real MIPS neg.[ds] instruction.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
90 lines
2 KiB
C
90 lines
2 KiB
C
/* IEEE754 floating point arithmetic
|
|
* single precision
|
|
*/
|
|
/*
|
|
* MIPS floating point support
|
|
* Copyright (C) 1994-2000 Algorithmics Ltd.
|
|
* http://www.algor.co.uk
|
|
*
|
|
* ########################################################################
|
|
*
|
|
* This program is free software; you can distribute it and/or modify it
|
|
* under the terms of the GNU General Public License (Version 2) as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
|
|
*
|
|
* ########################################################################
|
|
*/
|
|
|
|
|
|
#include "ieee754sp.h"
|
|
|
|
int ieee754sp_finite(ieee754sp x)
|
|
{
|
|
return SPBEXP(x) != SP_EMAX + 1 + SP_EBIAS;
|
|
}
|
|
|
|
ieee754sp ieee754sp_copysign(ieee754sp x, ieee754sp y)
|
|
{
|
|
CLEARCX;
|
|
SPSIGN(x) = SPSIGN(y);
|
|
return x;
|
|
}
|
|
|
|
|
|
ieee754sp ieee754sp_neg(ieee754sp x)
|
|
{
|
|
COMPXSP;
|
|
|
|
EXPLODEXSP;
|
|
CLEARCX;
|
|
FLUSHXSP;
|
|
|
|
/*
|
|
* Invert the sign ALWAYS to prevent an endless recursion on
|
|
* pow() in libc.
|
|
*/
|
|
/* quick fix up */
|
|
SPSIGN(x) ^= 1;
|
|
|
|
if (xc == IEEE754_CLASS_SNAN) {
|
|
ieee754sp y = ieee754sp_indef();
|
|
SETCX(IEEE754_INVALID_OPERATION);
|
|
SPSIGN(y) = SPSIGN(x);
|
|
return ieee754sp_nanxcpt(y, "neg");
|
|
}
|
|
|
|
if (ieee754sp_isnan(x)) /* but not infinity */
|
|
return ieee754sp_nanxcpt(x, "neg", x);
|
|
return x;
|
|
}
|
|
|
|
|
|
ieee754sp ieee754sp_abs(ieee754sp x)
|
|
{
|
|
COMPXSP;
|
|
|
|
EXPLODEXSP;
|
|
CLEARCX;
|
|
FLUSHXSP;
|
|
|
|
if (xc == IEEE754_CLASS_SNAN) {
|
|
SETCX(IEEE754_INVALID_OPERATION);
|
|
return ieee754sp_nanxcpt(ieee754sp_indef(), "abs");
|
|
}
|
|
|
|
if (ieee754sp_isnan(x)) /* but not infinity */
|
|
return ieee754sp_nanxcpt(x, "abs", x);
|
|
|
|
/* quick fix up */
|
|
SPSIGN(x) = 0;
|
|
return x;
|
|
}
|