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authorUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
committerUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
commitabfbdde177c3a7155070dda1b2cdc8292054cc26 (patch)
treee021306b596381fbf8311d2b7eb294e918ff17c8 /sysdeps/generic/s_catanh.c
parent86421aa57ecfd70963ae66848bd6a6dd3b8e0fe6 (diff)
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Update.
Diffstat (limited to 'sysdeps/generic/s_catanh.c')
-rw-r--r--sysdeps/generic/s_catanh.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/generic/s_catanh.c b/sysdeps/generic/s_catanh.c
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+++ b/sysdeps/generic/s_catanh.c
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+/* Return arc hyperbole tangent for double value.
+ Copyright (C) 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <complex.h>
+#include <math.h>
+
+#include "math_private.h"
+
+
+__complex__ double
+__catanh (__complex__ double x)
+{
+ __complex__ double res;
+ int rcls = fpclassify (__real__ x);
+ int icls = fpclassify (__imag__ x);
+
+ if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
+ {
+ if (icls == FP_INFINITE)
+ {
+ __real__ res = __copysign (0.0, __real__ x);
+ __imag__ res = __copysign (M_PI_2, __imag__ x);
+ }
+ else if (rcls == FP_INFINITE || rcls == FP_ZERO)
+ {
+ __real__ res = __copysign (0.0, __real__ x);
+ if (icls >= FP_ZERO)
+ __imag__ res = __copysign (M_PI_2, __imag__ x);
+ else
+ __imag__ res = __nan ("");
+ }
+ else
+ {
+ __real__ res = __nan ("");
+ __imag__ res = __nan ("");
+ }
+ }
+ else if (rcls == FP_ZERO && icls == FP_ZERO)
+ {
+ res = x;
+ }
+ else
+ {
+ double i2, num, den;
+
+ i2 = __imag__ x * __imag__ x;
+
+ num = 1.0 + __real__ x;
+ num = i2 + num * num;
+
+ den = 1.0 - __real__ x;
+ den = i2 + den * den;
+
+ __real__ res = 0.25 * (__ieee754_log (num) - __ieee754_log (den));
+
+ den = 1 - __real__ x * __real__ x - i2;
+
+ __imag__ res = 0.5 * __ieee754_atan2 (2.0 * __imag__ x, den);
+ }
+
+ return res;
+}
+weak_alias (__catanh, catanh)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__catanh, __catanhl)
+weak_alias (__catanh, catanhl)
+#endif