nan.h 1.7 KB

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  1. /* `NAN' constant for IEEE 754 machines.
  2. Copyright (C) 1992,1996,1997,1999,2004,2006 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #ifndef _MATH_H
  17. # error "Never use <bits/nan.h> directly; include <math.h> instead."
  18. #endif
  19. /* IEEE Not A Number. */
  20. /*
  21. * Copied from the common code and modified for TI tool wrapper.
  22. * Copyright (C) 2010 Texas Instruments Incorporated
  23. */
  24. #if __GNUC_PREREQ(3,3)
  25. # define NAN (__builtin_nanf (""))
  26. #elif defined __GNUC__ && ! defined __TI_TOOL_WRAPPER__
  27. # define NAN \
  28. (__extension__ \
  29. ((union { unsigned __l __attribute__ ((__mode__ (__SI__))); float __d; }) \
  30. { __l: 0x7fc00000UL }).__d)
  31. #else
  32. # include <endian.h>
  33. # if __BYTE_ORDER == __BIG_ENDIAN
  34. # define __nan_bytes { 0x7f, 0xc0, 0, 0 }
  35. # endif
  36. # if __BYTE_ORDER == __LITTLE_ENDIAN
  37. # define __nan_bytes { 0, 0, 0xc0, 0x7f }
  38. # endif
  39. static union { unsigned char __c[4]; float __d; } __nan_union
  40. = { __nan_bytes };
  41. # define NAN (__nan_union.__d)
  42. #endif /* GCC. */