Fix exp10 inaccuracy and exceptions (bugs 13884, 13914).

1 files changed, 46 insertions, 0 deletions

diff --git a/sysdeps/ieee754/ldbl-128ibm/e_exp10l.c b/sysdeps/ieee754/ldbl-128ibm/e_exp10l.c
new file mode 100644
index 0000000..b19e6c7
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm/e_exp10l.c
@@ -0,0 +1,46 @@
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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>
+#include <float.h>
+
+static const long double log10_high = 0x2.4d763776aaa2cp0L;
+static const long double log10_low = -0xf.a456a4a751f4b3d75c75c04c18p-56L;
+
+long double
+__ieee754_exp10l (long double arg)
+{
+  union ibm_extended_long_double u;
+  long double arg_high, arg_low;
+  long double exp_high, exp_low;
+
+  if (!__finitel (arg))
+    return __ieee754_expl (arg);
+  if (arg < LDBL_MIN_10_EXP - LDBL_DIG - 10)
+    return LDBL_MIN * LDBL_MIN;
+  else if (arg > LDBL_MAX_10_EXP + 1)
+    return LDBL_MAX * LDBL_MAX;
+
+  u.d = arg;
+  arg_high = u.dd[0];
+  arg_low = u.dd[1];
+  exp_high = arg_high * log10_high;
+  exp_low = arg_high * log10_low + arg_low * M_LN10l;
+  return __ieee754_expl (exp_high) * __ieee754_expl (exp_low);
+}
+strong_alias (__ieee754_exp10l, __exp10l_finite)