huge_val.h 1.8 KB

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  1. /* `HUGE_VAL' constant for IEEE 754 machines (where it is infinity).
  2. Used by <stdlib.h> and <math.h> functions for overflow.
  3. Blackfin version.
  4. Copyright (C) 1992, 95, 96, 97, 98, 99, 2000, 2004
  5. Free Software Foundation, Inc.
  6. This file is part of the GNU C Library.
  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. 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. You should have received a copy of the GNU Lesser General Public
  16. License along with the GNU C Library; if not, see
  17. <http://www.gnu.org/licenses/>. */
  18. #ifndef _MATH_H
  19. # error "Never use <bits/huge_val.h> directly; include <math.h> instead."
  20. #endif
  21. /* IEEE positive infinity (-HUGE_VAL is negative infinity). */
  22. #if __GNUC_PREREQ(3,3)
  23. # define HUGE_VAL (__builtin_huge_val())
  24. #elif __GNUC_PREREQ(2,96)
  25. # define HUGE_VAL (__extension__ 0x1.0p2047)
  26. #elif defined __GNUC__
  27. # define HUGE_VAL \
  28. (__extension__ \
  29. ((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; }) \
  30. { __l: 0x000000007ff00000ULL }).__d)
  31. #else /* not GCC */
  32. # include <endian.h>
  33. typedef union { unsigned char __c[8]; double __d; } __huge_val_t;
  34. # if __BYTE_ORDER == __BIG_ENDIAN
  35. # define __HUGE_VAL_bytes { 0, 0, 0, 0, 0x7f, 0xf0, 0, 0 }
  36. # endif
  37. # if __BYTE_ORDER == __LITTLE_ENDIAN
  38. # define __HUGE_VAL_bytes { 0, 0, 0xf0, 0x7f, 0, 0, 0, 0 }
  39. # endif
  40. static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
  41. # define HUGE_VAL (__huge_val.__d)
  42. #endif /* GCC. */