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glibc  2.9
feenablxcpt.c
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00001 /* Enable floating-point exceptions.
00002    Copyright (C) 2000 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by David Huggins-Daines <dhd@debian.org>, 2000
00005 
00006    The GNU C Library is free software; you can redistribute it and/or
00007    modify it under the terms of the GNU Lesser General Public
00008    License as published by the Free Software Foundation; either
00009    version 2.1 of the License, or (at your option) any later version.
00010 
00011    The GNU C Library is distributed in the hope that it will be useful,
00012    but WITHOUT ANY WARRANTY; without even the implied warranty of
00013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014    Lesser General Public License for more details.
00015 
00016    You should have received a copy of the GNU Lesser General Public
00017    License along with the GNU C Library; if not, write to the Free
00018    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00019    02111-1307 USA.  */
00020 
00021 #include <fenv.h>
00022 
00023 int
00024 feenableexcept (int excepts)
00025 {
00026   union { unsigned long long l; unsigned int sw[2]; } s;
00027   unsigned int old_exc;
00028 
00029   /* Get the current status word. */
00030   __asm__ ("fstd %%fr0,0(%1)" : "=m" (s.l) : "r" (&s.l) : "%r0");
00031 
00032   old_exc = s.sw[0] & FE_ALL_EXCEPT;
00033 
00034   s.sw[0] |= (excepts & FE_ALL_EXCEPT);
00035   __asm__ ("fldd 0(%0),%%fr0" : : "r" (&s.l), "m" (s.l) : "%r0");
00036 
00037   return old_exc;
00038 }