sysdeps/x86_64/fpu/feholdexcpt.c

   1 /* Store current floating-point environment and clear exceptions.
   2    Copyright (C) 2001, 2005, 2007 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <fenv.h>
  21
  22 int
  23 feholdexcept (fenv_t *envp)
  24 {
  25   unsigned int mxcsr;
  26   fenv_t temp;
  27
  28   /* Store the environment.  */
  29   __asm__ ("fnstenv %0\n"
  30            "stmxcsr %1" : "=m" (temp), "=m" (temp.__mxcsr));
  31   *envp = temp;
  32
  33   /* Now set all exceptions to non-stop, first the x87 FPU.  */
  34   temp.__control_word |= 0x3f;
  35
  36   /* And clear all exceptions.  */
  37   temp.__status_word &= ~0x3f;
  38
  39   __asm__ ("fldenv %0" : : "m" (temp));
  40
  41   /* Set the SSE MXCSR register.  */
  42   mxcsr = (envp->__mxcsr | 0x1f80) & ~0x3f;
  43   __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
  44
  45   return 0;
  46 }
  47 libm_hidden_def (feholdexcept)