glibc/sysdeps/arm/feenablxcpt.c

/* Enable floating-point exceptions.
   Copyright (C) 2001-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Philip Blundell <philb@gnu.org>, 2001.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library.  If not, see
   <http://www.gnu.org/licenses/>.  */

#include <fenv.h>
#include <fpu_control.h>
#include <arm-features.h>


int
feenableexcept (int excepts)
{
  if (ARM_HAVE_VFP)
    {
      unsigned long int new_exc, old_exc;

      _FPU_GETCW(new_exc);

      old_exc = (new_exc >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;

      excepts &= FE_ALL_EXCEPT;

      new_exc |= (excepts << FE_EXCEPT_SHIFT);

      _FPU_SETCW(new_exc);

      if (excepts != 0)
	{
	  /* VFPv3 and VFPv4 do not support trapping exceptions, so
	     test whether the relevant bits were set and fail if
	     not.  */
	  unsigned int temp;
	  _FPU_GETCW (temp);
	  if ((temp & (excepts << FE_EXCEPT_SHIFT))
	      != (excepts << FE_EXCEPT_SHIFT))
	    return -1;
	}

      return old_exc;
    }

  /* Unsupported, so return -1 for failure.  */
  return -1;
}