sysdeps/i386/fpu/fclrexcpt.c

   1 /* Clear given exceptions in current floating-point environment.
   2    Copyright (C) 1997,99,2000, 2001, 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   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 #include <ldsodefs.h>
  24 #include <dl-procinfo.h>
  25
  26 int
  27 __feclearexcept (int excepts)
  28 {
  29   fenv_t temp;
  30
  31   /* Mask out unsupported bits/exceptions.  */
  32   excepts &= FE_ALL_EXCEPT;
  33
  34   /* Bah, we have to clear selected exceptions.  Since there is no
  35      `fldsw' instruction we have to do it the hard way.  */
  36   __asm__ ("fnstenv %0" : "=m" (*&temp));
  37
  38   /* Clear the relevant bits.  */
  39   temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
  40
  41   /* Put the new data in effect.  */
  42   __asm__ ("fldenv %0" : : "m" (*&temp));
  43
  44   /* If the CPU supports SSE, we clear the MXCSR as well.  */
  45   if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
  46     {
  47       unsigned int xnew_exc;
  48
  49       /* Get the current MXCSR.  */
  50       __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
  51
  52       /* Clear the relevant bits.  */
  53       xnew_exc &= ~excepts;
  54
  55       /* Put the new data in effect.  */
  56       __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
  57     }
  58
  59   /* Success.  */
  60   return 0;
  61 }
  62
  63 #include <shlib-compat.h>
  64 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  65 strong_alias (__feclearexcept, __old_feclearexcept)
  66 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
  67 #endif
  68
  69 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);