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, write to the Free 19 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 20 02111-1307 USA. */ 21 22 #ifndef _MATH_H 23 # error "Never use <bits/huge_val.h> directly; include <math.h> instead." 24 #endif 25 26 /* IEEE positive infinity (-HUGE_VAL is negative infinity). */ 27 28 #if __GNUC_PREREQ(3,3) 29 # define HUGE_VAL (__builtin_huge_val()) 30 #elif __GNUC_PREREQ(2,96) 31 # define HUGE_VAL (__extension__ 0x1.0p2047) 32 #elif defined __GNUC__ 33 34 # define HUGE_VAL \ 35 (__extension__ \ 36 ((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; }) \ 37 { __l: 0x7ff0000000000000ULL }).__d) 38 39 #else /* not GCC */ 40 41 # include <endian.h> 42 43 typedef union { unsigned char __c[8]; double __d; } __huge_val_t; 44 45 # if __BYTE_ORDER == __BIG_ENDIAN 46 # define __HUGE_VAL_bytes { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } 47 # endif 48 # if __BYTE_ORDER == __LITTLE_ENDIAN 49 # define __HUGE_VAL_bytes { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } 50 # endif 51 52 static __huge_val_t __huge_val = { __HUGE_VAL_bytes }; 53 # define HUGE_VAL (__huge_val.__d) 54 55 #endif /* GCC. */ 56
