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55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* `HUGE_VAL' constant for IEEE 754 machines (where it is infinity).
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Used by <stdlib.h> and <math.h> functions for overflow.
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Copyright (C) 1992, 1995, 1996, 1997, 1999, 2000, 2004
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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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _MATH_H
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# error "Never use <bits/huge_val.h> directly; include <math.h> instead."
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#endif
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/* IEEE positive infinity (-HUGE_VAL is negative infinity). */
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#if __GNUC_PREREQ(3,3)
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# define HUGE_VAL (__builtin_huge_val())
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#elif __GNUC_PREREQ(2,96)
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# define HUGE_VAL (__extension__ 0x1.0p2047)
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#elif defined __GNUC__
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# define HUGE_VAL \
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(__extension__ \
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((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; }) \
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{ __l: 0x7ff0000000000000ULL }).__d)
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#else /* not GCC */
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# include <endian.h>
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typedef union { unsigned char __c[8]; double __d; } __huge_val_t;
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# if __BYTE_ORDER == __BIG_ENDIAN
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# define __HUGE_VAL_bytes { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }
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# endif
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# if __BYTE_ORDER == __LITTLE_ENDIAN
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# define __HUGE_VAL_bytes { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }
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# endif
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static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
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# define HUGE_VAL (__huge_val.__d)
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#endif /* GCC. */
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