w_log2_compat.c 1.9 KB

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  1. /* Copyright (C) 2011-2019 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
  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. #include <fenv.h>
  16. #include <math.h>
  17. #include <math_private.h>
  18. #include <math-svid-compat.h>
  19. #include <libm-alias-double.h>
  20. #if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29) \
  21. || defined NO_LONG_DOUBLE \
  22. || defined LONG_DOUBLE_COMPAT)
  23. /* wrapper log2(x) */
  24. double
  25. __log2_compat (double x)
  26. {
  27. if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
  28. {
  29. if (x == 0.0)
  30. {
  31. feraiseexcept (FE_DIVBYZERO);
  32. return __kernel_standard (x, x, 48); /* log2(0) */
  33. }
  34. else
  35. {
  36. feraiseexcept (FE_INVALID);
  37. return __kernel_standard (x, x, 49); /* log2(x<0) */
  38. }
  39. }
  40. return __ieee754_log2 (x);
  41. }
  42. # if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29)
  43. compat_symbol (libm, __log2_compat, log2, GLIBC_2_1);
  44. # endif
  45. # ifdef NO_LONG_DOUBLE
  46. weak_alias (__log2_compat, log2l)
  47. # endif
  48. # ifdef LONG_DOUBLE_COMPAT
  49. /* Work around gas bug "multiple versions for symbol". */
  50. weak_alias (__log2_compat, __log2_compat_alias)
  51. LONG_DOUBLE_COMPAT_CHOOSE_libm_log2l (
  52. compat_symbol (libm, __log2_compat_alias, log2l, FIRST_VERSION_libm_log2l), );
  53. # endif
  54. #endif