| /* Copyright (C) 2011-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <fenv.h> |
| #include <math.h> |
| #include <math_private.h> |
| #include <math-svid-compat.h> |
| #include <libm-alias-double.h> |
| |
| |
| #if LIBM_SVID_COMPAT |
| /* wrapper log2(x) */ |
| double |
| __log2 (double x) |
| { |
| if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_) |
| { |
| if (x == 0.0) |
| { |
| feraiseexcept (FE_DIVBYZERO); |
| return __kernel_standard (x, x, 48); /* log2(0) */ |
| } |
| else |
| { |
| feraiseexcept (FE_INVALID); |
| return __kernel_standard (x, x, 49); /* log2(x<0) */ |
| } |
| } |
| |
| return __ieee754_log2 (x); |
| } |
| libm_alias_double (__log2, log2) |
| #endif |
