ports/sysdeps/arm/feenablxcpt.c

   1 /* Enable floating-point exceptions.
   2    Copyright (C) 2001-2014 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Philip Blundell <philb@gnu.org>, 2001.
   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 <fpu_control.h>
  22 #include <arm-features.h>
  23
  24
  25 int
  26 feenableexcept (int excepts)
  27 {
  28   if (ARM_HAVE_VFP)
  29     {
  30       unsigned long int new_exc, old_exc;
  31
  32       _FPU_GETCW(new_exc);
  33
  34       old_exc = (new_exc >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
  35
  36       excepts &= FE_ALL_EXCEPT;
  37
  38       new_exc |= (excepts << FE_EXCEPT_SHIFT);
  39
  40       _FPU_SETCW(new_exc);
  41
  42       if (excepts != 0)
  43         {
  44           /* VFPv3 and VFPv4 do not support trapping exceptions, so
  45              test whether the relevant bits were set and fail if
  46              not.  */
  47           unsigned int temp;
  48           _FPU_GETCW (temp);
  49           if ((temp & (excepts << FE_EXCEPT_SHIFT))
  50               != (excepts << FE_EXCEPT_SHIFT))
  51             return -1;
  52         }
  53
  54       return old_exc;
  55     }
  56
  57   /* Unsupported, so return -1 for failure.  */
  58   return -1;
  59 }