sysdeps/i386/fpu/fsetexcptflg.c

   1 /* Set floating-point environment exception handling.
   2    Copyright (C) 1997-2022 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 <math.h>
  21 #include <unistd.h>
  22 #include <ldsodefs.h>
  23 #include <dl-procinfo.h>
  24
  25 int
  26 __fesetexceptflag (const fexcept_t *flagp, int excepts)
  27 {
  28   fenv_t temp;
  29
  30   /* Get the current environment.  We have to do this since we cannot
  31      separately set the status word.  */
  32   __asm__ ("fnstenv %0" : "=m" (*&temp));
  33
  34   temp.__status_word &= ~(excepts & FE_ALL_EXCEPT);
  35   temp.__status_word |= *flagp & excepts & FE_ALL_EXCEPT;
  36
  37   /* Store the new status word (along with the rest of the environment.
  38      Possibly new exceptions are set but they won't get executed unless
  39      the next floating-point instruction.  */
  40   __asm__ ("fldenv %0" : : "m" (*&temp));
  41
  42   /* If the CPU supports SSE, we set 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       /* Set the relevant bits.  */
  51       xnew_exc &= ~(excepts & FE_ALL_EXCEPT);
  52       xnew_exc |= *flagp & excepts & FE_ALL_EXCEPT;
  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 (__fesetexceptflag, __old_fesetexceptflag)
  65 compat_symbol (libm, __old_fesetexceptflag, fesetexceptflag, GLIBC_2_1);
  66 #endif
  67
  68 versioned_symbol (libm, __fesetexceptflag, fesetexceptflag, GLIBC_2_2);