sysdeps/i386/fpu/fclrexcpt.c

   1 /* Clear given exceptions in current floating-point environment.
   2    Copyright (C) 1997-2014 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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv.h>
  21 #include <unistd.h>
  22 #include <ldsodefs.h>
  23 #include <dl-procinfo.h>
  24
  25 int
  26 __feclearexcept (int excepts)
  27 {
  28   fenv_t temp;
  29
  30   /* Mask out unsupported bits/exceptions.  */
  31   excepts &= FE_ALL_EXCEPT;
  32
  33   /* Bah, we have to clear selected exceptions.  Since there is no
  34      `fldsw' instruction we have to do it the hard way.  */
  35   __asm__ ("fnstenv %0" : "=m" (*&temp));
  36
  37   /* Clear the relevant bits.  */
  38   temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
  39
  40   /* Put the new data in effect.  */
  41   __asm__ ("fldenv %0" : : "m" (*&temp));
  42
  43   /* If the CPU supports SSE, we clear the MXCSR as well.  */
  44   if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
  45     {
  46       unsigned int xnew_exc;
  47
  48       /* Get the current MXCSR.  */
  49       __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
  50
  51       /* Clear the relevant bits.  */
  52       xnew_exc &= ~excepts;
  53
  54       /* Put the new data in effect.  */
  55       __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
  56     }
  57
  58   /* Success.  */
  59   return 0;
  60 }
  61
  62 #include <shlib-compat.h>
  63 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  64 strong_alias (__feclearexcept, __old_feclearexcept)
  65 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
  66 #endif
  67
  68 libm_hidden_ver (__feclearexcept, feclearexcept)
  69 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);