huge_valf.h 1.8 KB

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  1. /* `HUGE_VALF' constant for IEEE 754 machines (where it is infinity).
  2. Used by <stdlib.h> and <math.h> functions for overflow.
  3. Copyright (C) 1992-2016 Free Software Foundation, Inc.
  4. This file is part of the GNU C Library.
  5. The GNU C Library is free software; you can redistribute it and/or
  6. modify it under the terms of the GNU Lesser General Public
  7. License as published by the Free Software Foundation; either
  8. version 2.1 of the License, or (at your option) any later version.
  9. The GNU C Library is distributed in the hope that it will be useful,
  10. but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12. Lesser General Public License for more details.
  13. You should have received a copy of the GNU Lesser General Public
  14. License along with the GNU C Library; if not, see
  15. <http://www.gnu.org/licenses/>. */
  16. #ifndef _MATH_H
  17. # error "Never use <bits/huge_valf.h> directly; include <math.h> instead."
  18. #endif
  19. /* IEEE positive infinity (-HUGE_VAL is negative infinity). */
  20. #if __GNUC_PREREQ(3,3)
  21. # define HUGE_VALF (__builtin_huge_valf())
  22. #elif __GNUC_PREREQ(2,96)
  23. # define HUGE_VALF (__extension__ 0x1.0p255f)
  24. #elif defined __GNUC__
  25. # define HUGE_VALF \
  26. (__extension__ \
  27. ((union { unsigned __l __attribute__((__mode__(__SI__))); float __d; }) \
  28. { __l: 0x7f800000UL }).__d)
  29. #else /* not GCC */
  30. typedef union { unsigned char __c[4]; float __f; } __huge_valf_t;
  31. # if __BYTE_ORDER == __BIG_ENDIAN
  32. # define __HUGE_VALF_bytes { 0x7f, 0x80, 0, 0 }
  33. # endif
  34. # if __BYTE_ORDER == __LITTLE_ENDIAN
  35. # define __HUGE_VALF_bytes { 0, 0, 0x80, 0x7f }
  36. # endif
  37. static __huge_valf_t __huge_valf = { __HUGE_VALF_bytes };
  38. # define HUGE_VALF (__huge_valf.__f)
  39. #endif /* GCC. */