/* Copyright (C) 2011-2016 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 <math.h> #include "math_private.h" #if defined(__UCLIBC_HAS_FENV__) #include <fenv.h> #endif /* wrapper log2(x) */ double log2 (double x) { #if defined(__UCLIBC_HAS_FENV__) 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) */ } } #endif /* __UCLIBC_HAS_FENV__ */ return __ieee754_log2 (x); } libm_hidden_def(log2)