96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/* Return arc hyperbole cosine for double value.
|
|
Copyright (C) 1997, 2006 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 <math.h>
|
|
|
|
|
|
__complex__ double
|
|
__cacosh (__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 = HUGE_VAL;
|
|
|
|
if (rcls == FP_NAN)
|
|
__imag__ res = __nan ("");
|
|
else
|
|
__imag__ res = __copysign ((rcls == FP_INFINITE
|
|
? (__real__ x < 0.0
|
|
? M_PI - M_PI_4 : M_PI_4)
|
|
: M_PI_2), __imag__ x);
|
|
}
|
|
else if (rcls == FP_INFINITE)
|
|
{
|
|
__real__ res = HUGE_VAL;
|
|
|
|
if (icls >= FP_ZERO)
|
|
__imag__ res = __copysign (signbit (__real__ x) ? M_PI : 0.0,
|
|
__imag__ x);
|
|
else
|
|
__imag__ res = __nan ("");
|
|
}
|
|
else
|
|
{
|
|
__real__ res = __nan ("");
|
|
__imag__ res = __nan ("");
|
|
}
|
|
}
|
|
else if (rcls == FP_ZERO && icls == FP_ZERO)
|
|
{
|
|
__real__ res = 0.0;
|
|
__imag__ res = __copysign (M_PI_2, __imag__ x);
|
|
}
|
|
else
|
|
{
|
|
__complex__ double y;
|
|
|
|
__real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
|
|
__imag__ y = 2.0 * __real__ x * __imag__ x;
|
|
|
|
y = __csqrt (y);
|
|
|
|
if (__real__ x < 0.0)
|
|
y = -y;
|
|
|
|
__real__ y += __real__ x;
|
|
__imag__ y += __imag__ x;
|
|
|
|
res = __clog (y);
|
|
|
|
/* We have to use the positive branch. */
|
|
if (__real__ res < 0.0)
|
|
res = -res;
|
|
}
|
|
|
|
return res;
|
|
}
|
|
weak_alias (__cacosh, cacosh)
|
|
#ifdef NO_LONG_DOUBLE
|
|
strong_alias (__cacosh, __cacoshl)
|
|
weak_alias (__cacosh, cacoshl)
|
|
#endif
|