sysdeps/ieee754/huge_val.h

   1 /* `HUGE_VAL' constants 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 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 Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #ifndef    _HUGE_VAL_H
  22 #define    _HUGE_VAL_H  1
  23
  24 #include <features.h>
  25 #include <sys/cdefs.h>
  26 #include <endian.h>
  27
  28 /* IEEE positive infinity (-HUGE_VAL is negative infinity).  */
  29
  30 #if __BYTE_ORDER == __BIG_ENDIAN
  31 #define __HUGE_VAL_bytes        { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }
  32 #endif
  33 #if __BYTE_ORDER == __LITTLE_ENDIAN
  34 #define __HUGE_VAL_bytes        { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }
  35 #endif
  36
  37 #define __huge_val_t    union { unsigned char __c[8]; double __d; }
  38 #ifdef  __GNUC__
  39 #define HUGE_VAL        (__extension__ \
  40                          ((__huge_val_t) { __c: __HUGE_VAL_bytes }).__d)
  41 #else   /* Not GCC.  */
  42 static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
  43 #define HUGE_VAL        (__huge_val.__d)
  44 #endif  /* GCC.  */
  45
  46
  47 /* ISO C 9X extensions: (float) HUGE_VALF and (long double) HUGE_VALL.  */
  48
  49 #ifdef __USE_ISOC9X
  50
  51 #if __BYTE_ORDER == __BIG_ENDIAN
  52 #define __HUGE_VALF_bytes       { 0x7f, 0x80, 0, 0 }
  53 #endif
  54 #if __BYTE_ORDER == __LITTLE_ENDIAN
  55 #define __HUGE_VALF_bytes       { 0, 0, 0x80, 0x7f }
  56 #endif
  57
  58 #define __huge_valf_t   union { unsigned char __c[4]; float __f; }
  59 #ifdef  __GNUC__
  60 #define HUGE_VALF       (__extension__ \
  61                          ((__huge_valf_t) { __c: __HUGE_VALF_bytes }).__f)
  62 #else   /* Not GCC.  */
  63 static __huge_valf_t __huge_valf = { __HUGE_VALF_bytes };
  64 #define HUGE_VALF       (__huge_valf.__f)
  65 #endif  /* GCC.  */
  66
  67
  68 /* Generally there is no separate `long double' format and it is the
  69    same as `double'.  */
  70 #define HUGE_VALL HUGE_VAL
  71
  72 #endif  /* __USE_ISOC9X.  */
  73
  74 #endif     /* huge_val.h */