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glibc  2.9
setfpucw.c
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00001 /* Set the FPU control word.
00002    Copyright (C) 1996, 1997, 1999, 2005 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <math.h>
00021 #include <fpu_control.h>
00022 
00023 #include <unistd.h>
00024 #include <ldsodefs.h>
00025 #include <dl-procinfo.h>
00026 #include <sysdep.h>
00027 
00028 void
00029 __setfpucw (fpu_control_t set)
00030 {
00031   if (GLRO (dl_hwcap) & HWCAP_ARM_VFP)
00032     {
00033       fpu_control_t cw;
00034 
00035       /* Fetch the current control word.  */
00036       _FPU_GETCW (cw);
00037 
00038       /* Preserve the reserved bits, and set the rest as the user
00039         specified (or the default, if the user gave zero).  */
00040       cw &= _FPU_RESERVED;
00041       cw |= set & ~_FPU_RESERVED;
00042 
00043       _FPU_SETCW (cw);
00044     }
00045 
00046   /* Do nothing if a VFP unit isn't present.  */
00047 }