1  /* Install given floating-point environment and raise exceptions.
       2     Copyright (C) 2000-2023 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 <string.h>
      21  
      22  int
      23  __feupdateenv (const fenv_t *envp)
      24  {
      25    union { unsigned long long l; unsigned int sw[2]; } s;
      26    fenv_t temp;
      27    /* Get the current exception status */
      28    __asm__ ("fstd %%fr0,0(%1)	\n\t"
      29             "fldd 0(%1),%%fr0	\n\t"
      30  	   : "=m" (s.l) : "r" (&s.l));
      31  
      32    /* Given environment with exception flags not cleared.  */
      33    if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
      34      {
      35        memcpy(&temp, envp, sizeof (fenv_t));
      36        temp.__status_word |= s.sw[0] & (FE_ALL_EXCEPT << 27);
      37      }
      38  
      39    /* Default environment with exception flags not cleared.  */
      40    if (envp == FE_DFL_ENV)
      41      temp.__status_word = s.sw[0] & (FE_ALL_EXCEPT << 27);
      42  
      43    /* All traps enabled and current exception flags not cleared.  */
      44    if (envp == FE_NOMASK_ENV)
      45      temp.__status_word = (s.sw[0] & (FE_ALL_EXCEPT << 27)) | FE_ALL_EXCEPT;
      46  
      47    /* Install new environment.  */
      48    __fesetenv (&temp);
      49    /* Success.  */
      50    return 0;
      51  }
      52  libm_hidden_def (__feupdateenv)
      53  weak_alias (__feupdateenv, feupdateenv)
      54  libm_hidden_weak (feupdateenv)