glibc/math/s_ctanhf.c
2011-10-22 13:17:30 -04:00

80 lines
2.0 KiB
C

/* Complex hyperbole tangent for float.
Copyright (C) 1997, 2005, 2011 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 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <complex.h>
#include <fenv.h>
#include <math.h>
#include <math_private.h>
__complex__ float
__ctanhf (__complex__ float x)
{
__complex__ float res;
if (__builtin_expect (!isfinite (__real__ x) || !isfinite (__imag__ x), 0))
{
if (__isinf_nsf (__real__ x))
{
__real__ res = __copysignf (1.0, __real__ x);
__imag__ res = __copysignf (0.0, __imag__ x);
}
else if (__imag__ x == 0.0)
{
res = x;
}
else
{
__real__ res = __nanf ("");
__imag__ res = __nanf ("");
if (__isinf_nsf (__imag__ x))
feraiseexcept (FE_INVALID);
}
}
else
{
float sin2ix, cos2ix;
float den;
__sincosf (2.0 * __imag__ x, &sin2ix, &cos2ix);
den = (__ieee754_coshf (2.0 * __real__ x) + cos2ix);
if (den == 0.0f)
{
__complex__ float ez = __cexpf (x);
__complex__ float emz = __cexpf (-x);
res = (ez - emz) / (ez + emz);
}
else
{
__real__ res = __ieee754_sinhf (2.0 * __real__ x) / den;
__imag__ res = sin2ix / den;
}
}
return res;
}
#ifndef __ctanhf
weak_alias (__ctanhf, ctanhf)
#endif