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glibc  2.9
fesetround.c
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00001 /* Set current rounding direction.
00002    Copyright (C) 1997, 2000, 2005 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by Richard Henderson <rth@tamu.edu>, 1997
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_libc.h>
00022 
00023 int
00024 fesetround (int round)
00025 {
00026   unsigned long fpcr;
00027 
00028   if (round & ~3)
00029     return 1;
00030 
00031   /* Get the current state.  */
00032   __asm__ __volatile__("excb; mf_fpcr %0" : "=f"(fpcr));
00033 
00034   /* Set the relevant bits.  */
00035   fpcr = ((fpcr & ~FPCR_ROUND_MASK)
00036          | ((unsigned long)round << FPCR_ROUND_SHIFT));
00037 
00038   /* Put the new state in effect.  */
00039   __asm__ __volatile__("mt_fpcr %0; excb" : : "f"(fpcr));
00040 
00041   return 0;
00042 }
00043 libm_hidden_def (fesetround)