glibc/sysdeps/i386/fpu/feenablxcpt.c

/* Enable floating-point exceptions.
   Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Andreas Jaeger <aj@suse.de>, 1999.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <fenv.h>

int
feenableexcept (int excepts)
{
  unsigned short int new_exc, old_exc;

  /* Get the current control word.  */
  __asm__ ("fstcw %0" : "=m" (*&new_exc));

  excepts &= FE_ALL_EXCEPT;
  old_exc = (~new_exc) & FE_ALL_EXCEPT;

  new_exc &= ~excepts;
  __asm__ ("fldcw %0" : : "m" (*&new_exc));

  return old_exc;
}