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glibc  2.9
fesetenv.c
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00001 /* Install given floating-point environment.
00002    Copyright (C) 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by Alexandre Oliva <aoliva@redhat.com>
00005    based on corresponding file in the MIPS port.
00006 
00007    The GNU C Library is free software; you can redistribute it and/or
00008    modify it under the terms of the GNU Lesser General Public
00009    License as published by the Free Software Foundation; either
00010    version 2.1 of the License, or (at your option) any later version.
00011 
00012    The GNU C Library is distributed in the hope that it will be useful,
00013    but WITHOUT ANY WARRANTY; without even the implied warranty of
00014    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015    Lesser General Public License for more details.
00016 
00017    You should have received a copy of the GNU Lesser General Public
00018    License along with the GNU C Library; if not, write to the Free
00019    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00020    02111-1307 USA.  */
00021 
00022 #include <fenv.h>
00023 #include <fpu_control.h>
00024 #include <shlib-compat.h>
00025 
00026 int
00027 __fesetenv (const fenv_t *envp)
00028 {
00029   fpu_control_t cw;
00030 
00031   /* We want to clear all EF bits for the default end IEEE.  */
00032 
00033   if (envp == FE_DFL_ENV)
00034     _FPU_SETFCW (_FPU_DEFAULT|FE_ALL_EXCEPT);
00035   else if (envp == FE_NOMASK_ENV)
00036     _FPU_SETFCW (_FPU_IEEE|FE_ALL_EXCEPT);
00037   else
00038     {
00039       fpu_control_t temp;
00040 
00041       _FPU_GETCW (temp);
00042       cw = *envp;
00043 
00044       /* If EF bits are cleared and the user requests them to be set,
00045         we have to fail, because there's no way to do it.  */
00046       if (~temp & cw & FE_ALL_EXCEPT)
00047        return -1;
00048 
00049       /* We clear EF bits by storing a 1 in them, so flip the
00050         FE_ALL_EXCEPT bits.  */
00051       cw = (cw & ~FE_ALL_EXCEPT) | (~cw & FE_ALL_EXCEPT);
00052       _FPU_SETFCW (cw);
00053     }
00054 
00055   /* Success.  */
00056   return 0;
00057 }
00058 
00059 libm_hidden_ver (__fesetenv, fesetenv)
00060 versioned_symbol (libm, __fesetenv, fesetenv, GLIBC_2_2);