sysdeps/ieee754/huge_val.h

   1 /* `HUGE_VAL' constant for IEEE 754 machines (where it is infinity).
   2    Used by <stdlib.h> and <math.h> functions for overflow.
   3
   4 Copyright (C) 1992, 1995 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 Library General Public License as
   9 published by the Free Software Foundation; either version 2 of the
  10 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 Library General Public License for more details.
  16
  17 You should have received a copy of the GNU Library General Public
  18 License along with the GNU C Library; see the file COPYING.LIB.  If
  19 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  20 Cambridge, MA 02139, USA.  */
  21
  22 #ifndef    _HUGE_VAL_H
  23 #define    _HUGE_VAL_H  1
  24
  25 #include <features.h>
  26 #include <sys/cdefs.h>
  27 #include <endian.h>
  28
  29 /* IEEE positive infinity (-HUGE_VAL is negative infinity).  */
  30
  31 #if __BYTE_ORDER == __BIG_ENDIAN
  32 #define __HUGE_VAL_bytes        { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }
  33 #endif
  34 #if __BYTE_ORDER == __LITTLE_ENDIAN
  35 #define __HUGE_VAL_bytes        { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }
  36 #endif
  37
  38 #define __huge_val_t    union { unsigned char __c[8]; double __d; }
  39 #ifdef  __GNUC__
  40 #define HUGE_VAL        (__extension__ \
  41                          ((__huge_val_t) { __c: __HUGE_VAL_bytes }).__d)
  42 #else   /* Not GCC.  */
  43 static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
  44 #define HUGE_VAL        (__huge_val.__d)
  45 #endif  /* GCC.  */
  46
  47
  48 /* GNU extensions: (float) HUGE_VALf and (long double) HUGE_VALl.  */
  49
  50 #ifdef  __USE_GNU
  51
  52 #if __BYTE_ORDER == __BIG_ENDIAN
  53 #define __HUGE_VALf_bytes       { 0x7f, 0x80, 0, 0 }
  54 #endif
  55 #if __BYTE_ORDER == __LITTLE_ENDIAN
  56 #define __HUGE_VALf_bytes       { 0, 0, 0x80, 0x7f }
  57 #endif
  58
  59 #define __huge_valf_t   union { unsigned char __c[4]; float __f; }
  60 #ifdef  __GNUC__
  61 #define HUGE_VALf       (__extension__ \
  62                          ((__huge_valf_t) { __c: __HUGE_VALf_bytes }).__f)
  63 #else   /* Not GCC.  */
  64 static __huge_valf_t __huge_valf = { __HUGE_VALf_bytes };
  65 #define HUGE_VALf       (__huge_valf.__f)
  66 #endif  /* GCC.  */
  67
  68 #if __BYTE_ORDER == __BIG_ENDIAN
  69 #define __HUGE_VALl_bytes       { 0x7f, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
  70 #endif
  71 #if __BYTE_ORDER == __LITTLE_ENDIAN
  72 #define __HUGE_VALl_bytes       { 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0x7f, 0, 0 }
  73 #endif
  74
  75 #define __huge_vall_t   union { unsigned char __c[12]; long double __ld; }
  76 #ifdef  __GNUC__
  77 #define HUGE_VALl       (__extension__ \
  78                          ((__huge_vall_t) { __c: __HUGE_VALl_bytes }).__ld)
  79 #else   /* Not GCC.  */
  80 static __huge_vall_t __huge_vall = { __HUGE_VALl_bytes };
  81 #define HUGE_VALl       (__huge_vall.__ld)
  82 #endif  /* GCC.  */
  83
  84 #endif  /* __USE_GNU.  */
  85
  86
  87 #endif     /* huge_val.h */