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/* Compute complex natural logarithm.
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
__clog (__complex__ double x)
{
__complex__ double result;
int rcls = fpclassify (__real__ x);
int icls = fpclassify (__imag__ x);
if (rcls == FP_ZERO && icls == FP_ZERO)
{
/* Real and imaginary part are 0.0. */
__imag__ result = signbit (__real__ x) ? M_PI : 0.0;
__imag__ result = __copysign (__imag__ result, __imag__ x);
/* Yes, the following line raises an exception. */
__real__ result = -1.0 / fabs (__real__ x);
}
else if (rcls != FP_NAN && icls != FP_NAN)
{
/* Neither real nor imaginary part is NaN. */
__real__ result = __ieee754_log (__ieee754_hypot (__real__ x,
__imag__ x));
__imag__ result = __ieee754_atan2 (__imag__ x, __real__ x);
}
else
{
__imag__ result = __nan ("");
if (rcls == FP_INFINITE || icls == FP_INFINITE)
/* Real or imaginary part is infinite. */
__real__ result = HUGE_VAL;
else
__real__ result = __nan ("");
}
return result;
}
weak_alias (__clog, clog)
#ifdef NO_LONG_DOUBLE
strong_alias (__clog, __clogl)
weak_alias (__clog, clogl)
#endif
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