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