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glibc  2.9
mathinline.h
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00001 /* Inline math functions for x86-64.
00002    Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by Andreas Jaeger <aj@suse.de>, 2002.
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 #ifndef _MATH_H
00022 # error "Never use <bits/mathinline.h> directly; include <math.h> instead."
00023 #endif
00024 
00025 #ifndef __extern_inline
00026 # define __MATH_INLINE __inline
00027 #else
00028 # define __MATH_INLINE __extern_inline
00029 #endif
00030 
00031 
00032 #if defined __USE_ISOC99 && defined __GNUC__ && __GNUC__ >= 2
00033 
00034 /* Test for negative number.  Used in the signbit() macro.  */
00035 __MATH_INLINE int
00036 __NTH (__signbitf (float __x))
00037 {
00038   __extension__ union { float __f; int __i; } __u = { __f: __x };
00039   return __u.__i < 0;
00040 }
00041 __MATH_INLINE int
00042 __NTH (__signbit (double __x))
00043 {
00044   __extension__ union { double __d; int __i[2]; } __u = { __d: __x };
00045   return __u.__i[1] < 0;
00046 }
00047 __MATH_INLINE int
00048 __NTH (__signbitl (long double __x))
00049 {
00050   __extension__ union { long double __l; int __i[3]; } __u = { __l: __x };
00051   return (__u.__i[2] & 0x8000) != 0;
00052 }
00053 #endif