sysdeps/x86_64/fpu/feenablxcpt.c

   1 /* Enable floating-point exceptions.
   2    Copyright (C) 2001, 2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Andreas Jaeger <aj@suse.de>, 2001.
   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
  23 int
  24 feenableexcept (int excepts)
  25 {
  26   unsigned short int new_exc, old_exc;
  27   unsigned int new;
  28
  29   excepts &= FE_ALL_EXCEPT;
  30
  31   /* Get the current control word of the x87 FPU.  */
  32   __asm__ ("fstcw %0" : "=m" (*&new_exc));
  33
  34   old_exc = (~new_exc) & FE_ALL_EXCEPT;
  35
  36   new_exc &= ~excepts;
  37   __asm__ ("fldcw %0" : : "m" (*&new_exc));
  38
  39   /* And now the same for the SSE MXCSR register.  */
  40   __asm__ ("stmxcsr %0" : "=m" (*&new));
  41
  42   /* The SSE exception masks are shifted by 7 bits.  */
  43   new &= ~(excepts << 7);
  44   __asm__ ("ldmxcsr %0" : : "m" (*&new));
  45
  46   return old_exc;
  47 }