sysdeps/x86_64/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 2001-2014 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    <http://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)