/* Copyright (C) 2005-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Richard Henderson <rth@redhat.com>, 2005.

   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, see

   <http://www.gnu.org/licenses/>.  */

#include <stdbool.h>

#include <math.h>

#include <complex.h>

attribute_hidden

long double _Complex

__divtc3 (long double a, long double b, long double c, long double d)

{

  long double denom, ratio, x, y;

  /* ??? We can get better behavior from logarithmic scaling instead of

     the division.  But that would mean starting to link libgcc against

     libm.  We could implement something akin to ldexp/frexp as gcc builtins

     fairly easily...  */

  if (fabsl (c) < fabsl (d))

    {

      ratio = c / d;

      denom = (c * ratio) + d;

      x = ((a * ratio) + b) / denom;

      y = ((b * ratio) - a) / denom;

    }

  else

    {

      ratio = d / c;

      denom = (d * ratio) + c;

      x = ((b * ratio) + a) / denom;

      y = (b - (a * ratio)) / denom;

    }

  /* Recover infinities and zeros that computed as NaN+iNaN; the only cases

     are nonzero/zero, infinite/finite, and finite/infinite.  */

  if (isnan (x) && isnan (y))

    {

      if (denom == 0.0 && (!isnan (a) || !isnan (b)))

	{

	  x = __copysignl (INFINITY, c) * a;

	  y = __copysignl (INFINITY, c) * b;

	}

      else if ((isinf (a) || isinf (b))

	       && isfinite (c) && isfinite (d))

	{

	  a = __copysignl (isinf (a) ? 1 : 0, a);

	  b = __copysignl (isinf (b) ? 1 : 0, b);

	  x = INFINITY * (a * c + b * d);

	  y = INFINITY * (b * c - a * d);

	}

      else if ((isinf (c) || isinf (d))

	       && isfinite (a) && isfinite (b))

	{

	  c = __copysignl (isinf (c) ? 1 : 0, c);

	  d = __copysignl (isinf (d) ? 1 : 0, d);

	  x = 0.0 * (a * c + b * d);

	  y = 0.0 * (b * c - a * d);

	}

    }

  return x + I * y;

}