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) 1992-2015 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 41 typedef 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 50 static __huge_val_t __huge_val = { __HUGE_VAL_bytes }; 51 # define HUGE_VAL (__huge_val.__d) 52 53 #endif /* GCC. */ 54