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Diffstat (limited to 'libm/w_log.c')
-rw-r--r-- | libm/w_log.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/libm/w_log.c b/libm/w_log.c new file mode 100644 index 000000000..ec4a2b005 --- /dev/null +++ b/libm/w_log.c @@ -0,0 +1,46 @@ +/* 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 __UCLIBC_HAS_FENV__ +#include <fenv.h> +#endif + +/* wrapper log(x) */ +double +log (double x) +{ +#if __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, 16); /* log(0) */ + } + else + { + feraiseexcept (FE_INVALID); + return __kernel_standard (x, x, 17); /* log(x<0) */ + } + } +#endif /* __UCLIBC_HAS_FENV__ */ + return __ieee754_log (x); +} +libm_hidden_def(log) |