sysdeps/i386/fpu/fraiseexcpt.c

   1 /* Raise given exceptions.
   2    Copyright (C) 1997,99,2000,01,02 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <fenv.h>
  22 #include <math.h>
  23
  24 int
  25 __feraiseexcept (int excepts)
  26 {
  27   /* Raise exceptions represented by EXPECTS.  But we must raise only
  28      one signal at a time.  It is important that if the overflow/underflow
  29      exception and the inexact exception are given at the same time,
  30      the overflow/underflow exception follows the inexact exception.  */
  31
  32   /* First: invalid exception.  */
  33   if ((FE_INVALID & excepts) != 0)
  34     {
  35       /* One example of a invalid operation is 0.0 / 0.0.  */
  36       double d;
  37       __asm__ __volatile__ ("fldz; fdiv %%st, %%st(0); fwait" : "=t" (d));
  38       (void) &d;
  39     }
  40
  41   /* Next: division by zero.  */
  42   if ((FE_DIVBYZERO & excepts) != 0)
  43     {
  44       double d;
  45       __asm__ __volatile__ ("fldz; fld1; fdivp %%st, %%st(1); fwait"
  46                             : "=t" (d));
  47       (void) &d;
  48     }
  49
  50   /* Next: overflow.  */
  51   if ((FE_OVERFLOW & excepts) != 0)
  52     {
  53       /* There is no way to raise only the overflow flag.  Do it the
  54          hard way.  */
  55       fenv_t temp;
  56
  57       /* Bah, we have to clear selected exceptions.  Since there is no
  58          `fldsw' instruction we have to do it the hard way.  */
  59       __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
  60
  61       /* Set the relevant bits.  */
  62       temp.__status_word |= FE_OVERFLOW;
  63
  64       /* Put the new data in effect.  */
  65       __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
  66
  67       /* And raise the exception.  */
  68       __asm__ __volatile__ ("fwait");
  69     }
  70
  71   /* Next: underflow.  */
  72   if ((FE_UNDERFLOW & excepts) != 0)
  73     {
  74       /* There is no way to raise only the underflow flag.  Do it the
  75          hard way.  */
  76       fenv_t temp;
  77
  78       /* Bah, we have to clear selected exceptions.  Since there is no
  79          `fldsw' instruction we have to do it the hard way.  */
  80       __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
  81
  82       /* Set the relevant bits.  */
  83       temp.__status_word |= FE_UNDERFLOW;
  84
  85       /* Put the new data in effect.  */
  86       __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
  87
  88       /* And raise the exception.  */
  89       __asm__ __volatile__ ("fwait");
  90     }
  91
  92   /* Last: inexact.  */
  93   if ((FE_INEXACT & excepts) != 0)
  94     {
  95       /* There is no way to raise only the inexact flag.  Do it the
  96          hard way.  */
  97       fenv_t temp;
  98
  99       /* Bah, we have to clear selected exceptions.  Since there is no
 100          `fldsw' instruction we have to do it the hard way.  */
 101       __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
 102
 103       /* Set the relevant bits.  */
 104       temp.__status_word |= FE_INEXACT;
 105
 106       /* Put the new data in effect.  */
 107       __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
 108
 109       /* And raise the exception.  */
 110       __asm__ __volatile__ ("fwait");
 111     }
 112
 113   /* Success.  */
 114   return 0;
 115 }
 116
 117 #include <shlib-compat.h>
 118 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
 119 strong_alias (__feraiseexcept, __old_feraiseexcept)
 120 compat_symbol (libm, __old_feraiseexcept, feraiseexcept, GLIBC_2_1);
 121 #endif
 122
 123 libm_hidden_ver (__feraiseexcept, feraiseexcept)
 124 versioned_symbol (libm, __feraiseexcept, feraiseexcept, GLIBC_2_2);