1/* `HUGE_VAL' constant for IEEE 754 machines (where it is infinity).
2 Used by <stdlib.h> and <math.h> functions for overflow.
3 Copyright (C) 1992-2014 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#ifndef _MATH_H
21# error "Never use <bits/huge_val.h> directly; include <math.h> instead."
22#endif
23
24/* IEEE positive infinity (-HUGE_VAL is negative infinity). */
25
26#if __GNUC_PREREQ(3,3)
27# define HUGE_VAL (__builtin_huge_val())
28#elif __GNUC_PREREQ(2,96)
29# define HUGE_VAL (__extension__ 0x1.0p2047)
30#elif defined __GNUC__
31
32# define HUGE_VAL \
33 (__extension__ \
34 ((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; }) \
35 { __l: 0x7ff0000000000000ULL }).__d)
36
37#else /* not GCC */
38
39# include <endian.h>
40
41typedef union { unsigned char __c[8]; double __d; } __huge_val_t;
42
43# if __BYTE_ORDER == __BIG_ENDIAN
44# define __HUGE_VAL_bytes { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }
45# endif
46# if __BYTE_ORDER == __LITTLE_ENDIAN
47# define __HUGE_VAL_bytes { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }
48# endif
49
50static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
51# define HUGE_VAL (__huge_val.__d)
52
53#endif /* GCC. */
54