sysdeps/powerpc/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 1997, 2005 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <fenv_libc.h>
  21
  22 int
  23 feholdexcept (fenv_t *envp)
  24 {
  25   fenv_union_t old, new;
  26
  27   /* Save the currently set exceptions.  */
  28   old.fenv = *envp = fegetenv_register ();
  29
  30   /* Clear everything except for the rounding modes and non-IEEE arithmetic
  31      flag.  */
  32   new.l[1] = old.l[1] & 7;
  33   new.l[0] = old.l[0];
  34
  35   /* If the old env had any eabled exceptions, then mask SIGFPE in the
  36      MSR FE0/FE1 bits.  This may allow the FPU to run faster because it
  37      always takes the default action and can not generate SIGFPE. */
  38   if ((old.l[1] & 0x000000F8) != 0)
  39     (void)__fe_mask_env ();
  40
  41   /* Put the new state in effect.  */
  42   fesetenv_register (new.fenv);
  43
  44   return 0;
  45 }
  46 libm_hidden_def (feholdexcept)