sysdeps/arm/setfpucw.c

   1 /* Set the FPU control word.
   2    Copyright (C) 1996-2017 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 <math.h>
  20 #include <fpu_control.h>
  21 #include <arm-features.h>
  22
  23
  24 void
  25 __setfpucw (fpu_control_t set)
  26 {
  27   fpu_control_t fpscr, new_fpscr;
  28
  29   /* Do nothing if a VFP unit isn't present.  */
  30   if (!ARM_HAVE_VFP)
  31     return;
  32
  33   _FPU_GETCW (fpscr);
  34
  35   /* Preserve the reserved bits, and set the rest as the user
  36      specified (or the default, if the user gave zero).  */
  37   new_fpscr = fpscr & _FPU_RESERVED;
  38   new_fpscr |= set & ~_FPU_RESERVED;
  39
  40   /* Write FPSCR if changed.  */
  41   if (new_fpscr != fpscr)
  42     _FPU_SETCW (fpscr);
  43 }