libm/i386/fedisblxcpt.c

   1 /* Disable floating-point exceptions.
   2    Copyright (C) 1999, 2000, 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Andreas Jaeger <aj@suse.de>, 1999.
   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
  24 int
  25 fedisableexcept (int excepts)
  26 {
  27   unsigned short int new_exc, old_exc;
  28
  29   /* Get the current control word.  */
  30   __asm__ ("fstcw %0" : "=m" (*&new_exc));
  31
  32   old_exc = (~new_exc) & FE_ALL_EXCEPT;
  33
  34   excepts &= FE_ALL_EXCEPT;
  35
  36   new_exc |= excepts;
  37   __asm__ ("fldcw %0" : : "m" (*&new_exc));
  38
  39 #if 0
  40   /* If the CPU supports SSE we set the MXCSR as well.  */
  41   if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
  42     {
  43       unsigned int xnew_exc;
  44
  45       /* Get the current control word.  */
  46       __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
  47
  48       xnew_exc |= excepts << 7;
  49
  50       __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
  51     }
  52 #endif
  53
  54   return old_exc;
  55 }