sysdeps/i386/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 1997, 1999, 2003, 2004, 2005 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 <unistd.h>
  23 #include <ldsodefs.h>
  24 #include <dl-procinfo.h>
  25
  26 int
  27 feholdexcept (fenv_t *envp)
  28 {
  29   unsigned short int work;
  30
  31   /* Store the environment.  */
  32   __asm__ ("fnstenv %0" : "=m" (*envp));
  33
  34   /* Now set all exceptions to non-stop.  */
  35   work = envp->__control_word | 0x3f;
  36   __asm__ ("fldcw %0" : : "m" (*&work));
  37
  38   /* If the CPU supports SSE we set the MXCSR as well.  */
  39   if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
  40     {
  41       unsigned int xwork;
  42
  43       /* Get the current control word.  */
  44       __asm__ ("stmxcsr %0" : "=m" (*&xwork));
  45
  46       /* Set all exceptions to non-stop.  */
  47       xwork |= 0x1f80;
  48
  49       __asm__ ("ldmxcsr %0" : : "m" (*&xwork));
  50     }
  51
  52   return 0;
  53 }
  54 libm_hidden_def (feholdexcept)