1  /* Store current floating-point environment and clear exceptions.
       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  __feholdexcept (fenv_t *envp)
      23  {
      24    unsigned int mxcsr;
      25  
      26    /* Store the environment.  Recall that fnstenv has a side effect of
      27       masking all exceptions.  Then clear all exceptions.  */
      28    __asm__ ("fnstenv %0\n\t"
      29  	   "stmxcsr %1\n\t"
      30  	   "fnclex"
      31  	   : "=m" (*envp), "=m" (envp->__mxcsr));
      32  
      33    /* Set the SSE MXCSR register.  */
      34    mxcsr = (envp->__mxcsr | 0x1f80) & ~0x3f;
      35    __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
      36  
      37    return 0;
      38  }
      39  libm_hidden_def (__feholdexcept)
      40  weak_alias (__feholdexcept, feholdexcept)
      41  libm_hidden_weak (feholdexcept)