sysdeps/x86_64/fpu/fclrexcpt.c

   1 /* Clear given exceptions in current floating-point environment.
   2    Copyright (C) 2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <fenv.h>
  21
  22 int
  23 feclearexcept (int excepts)
  24 {
  25   fenv_t temp;
  26   unsigned int mxcsr;
  27
  28   /* Mask out unsupported bits/exceptions.  */
  29   excepts &= FE_ALL_EXCEPT;
  30
  31   /* Bah, we have to clear selected exceptions.  Since there is no
  32      `fldsw' instruction we have to do it the hard way.  */
  33   __asm__ ("fnstenv %0" : "=m" (*&temp));
  34
  35   /* Clear the relevant bits.  */
  36   temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
  37
  38   /* Put the new data in effect.  */
  39   __asm__ ("fldenv %0" : : "m" (*&temp));
  40
  41   /* And the same procedure for SSE.  */
  42   __asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
  43
  44   /* Clear the relevant bits.  */
  45   mxcsr &= ~excepts;
  46
  47   /* And put them into effect.  */
  48   __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
  49
  50   /* Success.  */
  51   return 0;
  52 }