sysdeps/i386/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 1997, 1999, 2003, 2004, 2005, 2007
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include <fenv.h>
  23 #include <unistd.h>
  24 #include <ldsodefs.h>
  25 #include <dl-procinfo.h>
  26
  27 int
  28 feholdexcept (fenv_t *envp)
  29 {
  30   fenv_t temp;
  31
  32   /* Store the environment.  */
  33   __asm__ ("fnstenv %0" : "=m" (temp));
  34   *envp = temp;
  35
  36   /* Now set all exceptions to non-stop.  */
  37   temp.__control_word |= 0x3f;
  38
  39   /* And clear all exceptions.  */
  40   temp.__status_word &= ~0x3f;
  41
  42   __asm__ ("fldenv %0" : : "m" (temp));
  43
  44   /* If the CPU supports SSE we set the MXCSR as well.  */
  45   if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
  46     {
  47       unsigned int xwork;
  48
  49       /* Get the current control word.  */
  50       __asm__ ("stmxcsr %0" : "=m" (*&xwork));
  51
  52       /* Set all exceptions to non-stop and clear them.  */
  53       xwork = (xwork | 0x1f80) & ~0x3f;
  54
  55       __asm__ ("ldmxcsr %0" : : "m" (*&xwork));
  56     }
  57
  58   return 0;
  59 }
  60 libm_hidden_def (feholdexcept)