1  /* Clear given exceptions in current floating-point environment.
       2     Copyright (C) 1997-2023 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  #include <unistd.h>
      21  #include <ldsodefs.h>
      22  #include <dl-procinfo.h>
      23  
      24  int
      25  __feclearexcept (int excepts)
      26  {
      27    fenv_t temp;
      28  
      29    /* Mask out unsupported bits/exceptions.  */
      30    excepts &= FE_ALL_EXCEPT;
      31  
      32    /* Bah, we have to clear selected exceptions.  Since there is no
      33       `fldsw' instruction we have to do it the hard way.  */
      34    __asm__ ("fnstenv %0" : "=m" (*&temp));
      35  
      36    /* Clear the relevant bits.  */
      37    temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
      38  
      39    /* Put the new data in effect.  */
      40    __asm__ ("fldenv %0" : : "m" (*&temp));
      41  
      42    /* If the CPU supports SSE, we clear the MXCSR as well.  */
      43    if (CPU_FEATURE_USABLE (SSE))
      44      {
      45        unsigned int xnew_exc;
      46  
      47        /* Get the current MXCSR.  */
      48        __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
      49  
      50        /* Clear the relevant bits.  */
      51        xnew_exc &= ~excepts;
      52  
      53        /* Put the new data in effect.  */
      54        __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
      55      }
      56  
      57    /* Success.  */
      58    return 0;
      59  }
      60  
      61  #include <shlib-compat.h>
      62  #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
      63  strong_alias (__feclearexcept, __old_feclearexcept)
      64  compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
      65  #endif
      66  
      67  libm_hidden_ver (__feclearexcept, feclearexcept)
      68  versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);