1  /* Clear given exceptions in current floating-point environment.
       2     Copyright (C) 2001-2023 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, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <fenv.h>
      20  
      21  int
      22  feclearexcept (int excepts)
      23  {
      24    fenv_t temp;
      25    unsigned int mxcsr;
      26  
      27    /* Mask out unsupported bits/exceptions.  */
      28    excepts &= FE_ALL_EXCEPT;
      29  
      30    /* Bah, we have to clear selected exceptions.  Since there is no
      31       `fldsw' instruction we have to do it the hard way.  */
      32    __asm__ ("fnstenv %0" : "=m" (*&temp));
      33  
      34    /* Clear the relevant bits.  */
      35    temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
      36  
      37    /* Put the new data in effect.  */
      38    __asm__ ("fldenv %0" : : "m" (*&temp));
      39  
      40    /* And the same procedure for SSE.  */
      41    __asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
      42  
      43    /* Clear the relevant bits.  */
      44    mxcsr &= ~excepts;
      45  
      46    /* And put them into effect.  */
      47    __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
      48  
      49    /* Success.  */
      50    return 0;
      51  }
      52  libm_hidden_def (feclearexcept)