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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_scalb.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_scalb.c')
-rw-r--r--libm/w_scalb.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/libm/w_scalb.c b/libm/w_scalb.c
new file mode 100644
index 000000000..c4cecc322
--- /dev/null
+++ b/libm/w_scalb.c
@@ -0,0 +1,86 @@
+/* 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 <errno.h>
+
+static double
+__attribute__ ((noinline))
+sysv_scalb (double x, double fn)
+{
+ double z = __ieee754_scalb (x, fn);
+
+ if (__builtin_expect (isinf (z), 0))
+ {
+ if (isfinite (x))
+ return __kernel_standard (x, fn, 32); /* scalb overflow */
+ else
+ __set_errno (ERANGE);
+ }
+ else if (__builtin_expect (z == 0.0, 0) && z != x)
+ return __kernel_standard (x, fn, 33); /* scalb underflow */
+
+ return z;
+}
+#endif /* __UCLIBC_HAS_FENV__ */
+
+/* Here might be a check like "#if defined __UCLIBC_SUSV3_LEGACY__"
+ * but because there is a sysv_scalb() func, it was decided
+ * not to check yhis macro.
+ */
+
+/* Wrapper scalb */
+double
+scalb (double x, double fn)
+{
+#if __UCLIBC_HAS_FENV__
+ if (__builtin_expect (_LIB_VERSION == _SVID_,0))
+ return sysv_scalb (x, fn);
+ else
+ {
+ double z = __ieee754_scalb (x, fn);
+
+ if (__builtin_expect (!isfinite (z) || z == 0.0, 0))
+ {
+ if (isnan (z))
+ {
+ if (!isnan (x) && !isnan (fn))
+ __set_errno (EDOM);
+ }
+ else if (isinf (z))
+ {
+ if (!isinf (x) && !isinf (fn))
+ __set_errno (ERANGE);
+ }
+ else
+ {
+ /* z == 0. */
+ if (x != 0.0 && !isinf (fn))
+ __set_errno (ERANGE);
+ }
+ }
+ return z;
+ }
+#else
+ return __ieee754_scalb (x, fn);
+#endif /* __UCLIBC_HAS_FENV__ */
+}
+libm_hidden_def(scalb)