sysdeps/i386/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 1997-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv.h>
  21 #include <unistd.h>
  22 #include <ldsodefs.h>
  23 #include <dl-procinfo.h>
  24
  25 int
  26 __feholdexcept (fenv_t *envp)
  27 {
  28   /* Store the environment.  Recall that fnstenv has a side effect of
  29      masking all exceptions.  Then clear all exceptions.  */
  30   __asm__ volatile ("fnstenv %0; fnclex" : "=m" (*envp));
  31
  32   /* If the CPU supports SSE we set the MXCSR as well.  */
  33   if (HAS_CPU_FEATURE (SSE))
  34     {
  35       unsigned int xwork;
  36
  37       /* Get the current control word.  */
  38       __asm__ ("stmxcsr %0" : "=m" (envp->__eip));
  39
  40       /* Set all exceptions to non-stop and clear them.  */
  41       xwork = (envp->__eip | 0x1f80) & ~0x3f;
  42
  43       __asm__ ("ldmxcsr %0" : : "m" (*&xwork));
  44     }
  45
  46   return 0;
  47 }
  48 libm_hidden_def (__feholdexcept)
  49 weak_alias (__feholdexcept, feholdexcept)
  50 libm_hidden_weak (feholdexcept)