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/* Raise given exceptions.
Copyright (C) 2001-2017 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <math.h>
int
feraiseexcept (int excepts)
{
/* Raise exceptions represented by EXPECTS. But we must raise only
one signal at a time. It is important that 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 an invalid operation is 0.0 / 0.0. */
float f = 0.0;
__asm__ __volatile__ ("divss %0, %0 " : : "x" (f));
(void) &f;
}
/* Next: division by zero. */
if ((FE_DIVBYZERO & excepts) != 0)
{
float f = 1.0;
float g = 0.0;
__asm__ __volatile__ ("divss %1, %0" : : "x" (f), "x" (g));
(void) &f;
}
/* Next: overflow. */
if ((FE_OVERFLOW & excepts) != 0)
{
/* XXX: Is it ok to only set the x87 FPU? */
/* 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__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
/* Set the relevant bits. */
temp.__status_word |= FE_OVERFLOW;
/* Put the new data in effect. */
__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
/* And raise the exception. */
__asm__ __volatile__ ("fwait");
}
/* Next: underflow. */
if ((FE_UNDERFLOW & excepts) != 0)
{
/* XXX: Is it ok to only set the x87 FPU? */
/* There is no way to raise only the underflow 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__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
/* Set the relevant bits. */
temp.__status_word |= FE_UNDERFLOW;
/* Put the new data in effect. */
__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
/* And raise the exception. */
__asm__ __volatile__ ("fwait");
}
/* Last: inexact. */
if ((FE_INEXACT & excepts) != 0)
{
/* XXX: Is it ok to only set the x87 FPU? */
/* There is no way to raise only the inexact 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__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
/* Set the relevant bits. */
temp.__status_word |= FE_INEXACT;
/* Put the new data in effect. */
__asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
/* And raise the exception. */
__asm__ __volatile__ ("fwait");
}
/* Success. */
return 0;
}
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