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, 1995, 1996, 1997, 1999, 2000, 2004 4 Free Software Foundation, Inc. 5 This file is part of the GNU C Library. 6 7 The GNU C Library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU Lesser General Public 9 License as published by the Free Software Foundation; either 10 version 2.1 of the License, or (at your option) any later version. 11 12 The GNU C Library is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 Lesser General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public 18 License along with the GNU C Library; if not, see 19 <http://www.gnu.org/licenses/>. */ 20 21 #ifndef _MATH_H 22 # error "Never use <bits/huge_val.h> directly; include <math.h> instead." 23 #endif 24 25 /* IEEE positive infinity (-HUGE_VAL is negative infinity). */ 26 27 #if __GNUC_PREREQ(3,3) 28 # define HUGE_VAL (__builtin_huge_val()) 29 #elif __GNUC_PREREQ(2,96) 30 # define HUGE_VAL (__extension__ 0x1.0p2047) 31 #elif defined __GNUC__ 32 33 # define HUGE_VAL \ 34 (__extension__ \ 35 ((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; }) \ 36 { __l: 0x7ff0000000000000ULL }).__d) 37 38 #else /* not GCC */ 39 40 # include <endian.h> 41 42 typedef union { unsigned char __c[8]; double __d; } __huge_val_t; 43 44 # if __BYTE_ORDER == __BIG_ENDIAN 45 # define __HUGE_VAL_bytes { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } 46 # endif 47 # if __BYTE_ORDER == __LITTLE_ENDIAN 48 # define __HUGE_VAL_bytes { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } 49 # endif 50 51 static __huge_val_t __huge_val = { __HUGE_VAL_bytes }; 52 # define HUGE_VAL (__huge_val.__d) 53 54 #endif /* GCC. */ 55