w_log2_template.c 1.4 KB

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  1. /* Wrapper to set errno for log2.
  2. Copyright (C) 2017-2019 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, see
  14. <http://www.gnu.org/licenses/>. */
  15. /* Only build wrappers from the templates for the types that define the macro
  16. below. This macro is set in math-type-macros-<type>.h in sysdeps/generic
  17. for each floating-point type. */
  18. #if __USE_WRAPPER_TEMPLATE
  19. # include <errno.h>
  20. # include <fenv.h>
  21. # include <math.h>
  22. # include <math_private.h>
  23. FLOAT
  24. M_DECL_FUNC (__log2) (FLOAT x)
  25. {
  26. if (__glibc_unlikely (islessequal (x, M_LIT (0.0))))
  27. {
  28. if (x == 0)
  29. /* Pole error: log2(0). */
  30. __set_errno (ERANGE);
  31. else
  32. /* Domain error: log2(<0). */
  33. __set_errno (EDOM);
  34. }
  35. return M_SUF (__ieee754_log2) (x);
  36. }
  37. declare_mgen_alias (__log2, log2)
  38. #endif /* __USE_WRAPPER_TEMPLATE. */