diff options
Diffstat (limited to 'sysdeps/libm-ieee754/s_catanh.c')
| -rw-r--r-- | sysdeps/libm-ieee754/s_catanh.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_catanh.c b/sysdeps/libm-ieee754/s_catanh.c new file mode 100644 index 0000000000..6c4b10e3db --- /dev/null +++ b/sysdeps/libm-ieee754/s_catanh.c @@ -0,0 +1,84 @@ +/* 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 / den); + + den = 1 - __real__ x * __real__ x - i2; + + __imag__ res = 0.5 * __atan ((2.0 * __imag__ x) / den); + } + + return res; +} +weak_alias (__catanh, catanh) +#ifdef NO_LONG_DOUBLE +strong_alias (__catanh, __catanhl) +weak_alias (__catanh, catanhl) +#endif |