49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* `NAN' constant for IEEE 754 machines.
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Copyright (C) 1992, 1996, 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _MATH_H
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# error "Never use <bits/nan.h> directly; include <math.h> instead."
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#endif
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/* IEEE Not A Number. */
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#ifdef __GNUC__
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# define NAN \
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(__extension__ \
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((union { unsigned __l __attribute__((__mode__(__SI__))); float __d; }) \
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{ __l: 0x7fc00000UL }).__d)
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#else
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# include <endian.h>
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# if __BYTE_ORDER == __BIG_ENDIAN
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# define __nan_bytes { 0x7f, 0xc0, 0, 0 }
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# endif
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# if __BYTE_ORDER == __LITTLE_ENDIAN
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# define __nan_bytes { 0, 0, 0xc0, 0x7f }
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# endif
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static union { unsigned char __c[4]; double __d; } __nan = { __nan_bytes };
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# define NAN (__nan.__d)
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#endif /* GCC. */
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