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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [linux/] [cmath/] [s_catanh.c] - Blame information for rev 829

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Line No. Rev Author Line
1 207 jeremybenn
/* Return arc hyperbole tangent for double value.
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   Copyright (C) 1997 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, write to the Free
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   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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   02111-1307 USA.  */
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#include <complex.h>
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#include <math.h>
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#include "math_private.h"
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__complex__ double
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__catanh (__complex__ double x)
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{
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  __complex__ double res;
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  int rcls = fpclassify (__real__ x);
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  int icls = fpclassify (__imag__ x);
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  if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
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    {
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      if (icls == FP_INFINITE)
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        {
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          __real__ res = __copysign (0.0, __real__ x);
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          __imag__ res = __copysign (M_PI_2, __imag__ x);
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        }
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      else if (rcls == FP_INFINITE || rcls == FP_ZERO)
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        {
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          __real__ res = __copysign (0.0, __real__ x);
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          if (icls >= FP_ZERO)
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            __imag__ res = __copysign (M_PI_2, __imag__ x);
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          else
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            __imag__ res = __nan ("");
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        }
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      else
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        {
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          __real__ res = __nan ("");
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          __imag__ res = __nan ("");
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        }
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    }
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  else if (rcls == FP_ZERO && icls == FP_ZERO)
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    {
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      res = x;
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    }
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  else
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    {
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      double i2, num, den;
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      i2 = __imag__ x * __imag__ x;
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      num = 1.0 + __real__ x;
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      num = i2 + num * num;
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      den = 1.0 - __real__ x;
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      den = i2 + den * den;
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      __real__ res = 0.25 * (__ieee754_log (num) - __ieee754_log (den));
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      den = 1 - __real__ x * __real__ x - i2;
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      __imag__ res = 0.5 * __ieee754_atan2 (2.0 * __imag__ x, den);
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    }
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  return res;
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}
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weak_alias (__catanh, catanh)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__catanh, __catanhl)
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weak_alias (__catanh, catanhl)
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#endif

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