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/* Raise given exceptions.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <fenv.h>
#include <math.h>
void
feraiseexcept (int excepts)
{
/* Raise exceptions represented by EXPECTS. But we must raise only
one signal at a time. It is important the if the overflow/underflow
exception and the inexact exception are given at the same time,
the overflow/underflow exception follows the inexact exception. */
/* First: invalid exception. */
if ((FE_INVALID & excepts) != 0)
{
/* One example of a invalid operation is 0.0 / 0.0. */
double d;
__asm__ ("fldz; fdiv %%st, %%st(0); fwait" : "=t" (d));
(void) &d;
}
/* Next: division by zero. */
if ((FE_DIVBYZERO & excepts) != 0)
{
double d;
__asm__ ("fldz; fld1; fdivp %%st, %%st(1); fwait" : "=t" (d));
(void) &d;
}
/* Next: overflow. */
if ((FE_OVERFLOW & excepts) != 0)
{
/* There is no way to raise only the overflow flag. Do it the
hard way. */
fenv_t temp;
/* Bah, we have to clear selected exceptions. Since there is no
`fldsw' instruction we have to do it the hard way. */
__asm__ ("fnstenv %0" : "=m" (*&temp));
/* Set the relevant bits. */
temp.status_word |= FE_OVERFLOW;
/* Put the new data in effect. */
__asm__ ("fldenv %0" : : "m" (*&temp));
/* And raise the exception. */
__asm__ ("fwait");
}
/* Next: underflow. */
if ((FE_UNDERFLOW & excepts) != 0)
{
/* There is no way to raise only the overflow flag. Do it the
hard way. */
fenv_t temp;
/* Bah, we have to clear selected exceptions. Since there is no
`fldsw' instruction we have to do it the hard way. */
__asm__ ("fnstenv %0" : "=m" (*&temp));
/* Set the relevant bits. */
temp.status_word |= FE_UNDERFLOW;
/* Put the new data in effect. */
__asm__ ("fldenv %0" : : "m" (*&temp));
/* And raise the exception. */
__asm__ ("fwait");
}
/* Last: inexact. */
if ((FE_INEXACT & excepts) != 0)
{
long double d;
__asm__ ("fmul %%st, %%st(0); fwait" : "=t" (d) : "0" (LDBL_MAX));
(void) &d;
}
}
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