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authorSergey Cherkashin <4erkashin@list.ru>2017-10-03 15:26:34 +0300
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2017-11-03 20:23:10 +0100
commitea38f4d89c9698895b1cf53a5946429dc1d8bbaa (patch)
treee05828ca1fedf55f104b837bc9c44215c2978e99 /libm/w_log2l.c
parent68de9946e914d8c30dcc6667a059ea59e5b74cac (diff)
math: add exception handling functionality
According to standards SVID and SYSV. Modified lgamma calling in case when 'signgam' variable should not be used. Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>
Diffstat (limited to 'libm/w_log2l.c')
-rw-r--r--libm/w_log2l.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/libm/w_log2l.c b/libm/w_log2l.c
new file mode 100644
index 000000000..cbe45ce85
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+++ b/libm/w_log2l.c
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+/* 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
+
+#if !defined __NO_LONG_DOUBLE_MATH
+/* wrapper log2l(x) */
+long double
+log2l (long double x)
+{
+# if __UCLIBC_HAS_FENV__
+ if (__builtin_expect (islessequal (x, 0.0L), 0) && _LIB_VERSION != _IEEE_)
+ {
+ if (x == 0.0L)
+ {
+ feraiseexcept (FE_DIVBYZERO);
+ return __kernel_standard_l (x, x, 248); /* log2(0) */
+ }
+ else
+ {
+ feraiseexcept (FE_INVALID);
+ return __kernel_standard_l (x, x, 249); /* log2(x<0) */
+ }
+ }
+# endif /* __UCLIBC_HAS_FENV__ */
+ return (long double) __ieee754_log2 ((double) x);
+}
+#endif /* __NO_LONG_DOUBLE_MATH */