/* Round to nearest integer value, rounding halfway cases to even.

   ldbl-128ibm version.

   Copyright (C) 2016-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   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 <math.h>

#include <math_private.h>

long double

__roundevenl (long double x)

{

  double xh, xl, hi;

  ldbl_unpack (x, &xh, &xl);

  if (xh != 0 && isfinite (xh))

    {

      hi = __roundeven (xh);

      if (hi != xh)

	{

	  /* The high part is not an integer; the low part only

	     affects the result if the high part is exactly half way

	     between two integers and the low part is nonzero in the

	     opposite direction to the rounding of the high part.  */

	  double diff = hi - xh;

	  if (fabs (diff) == 0.5)

	    {

	      if (xl < 0 && diff > 0)

		xh = hi - 1;

	      else if (xl > 0 && diff < 0)

		xh = hi + 1;

	      else

		xh = hi;

	    }

	  else

	    xh = hi;

	  xl = 0;

	}

      else

	{

	  /* The high part is a nonzero integer.  Rounding the low

	     part to nearest, ties round to even, is always correct,

	     as a high part that is an odd integer together with a low

	     part with magnitude 0.5 is not a valid long double.  */

	  xl = __roundeven (xl);

	  xh = hi;

	  ldbl_canonicalize_int (&xh, &xl);

	}

    }

  else

    /* Quiet signaling NaN arguments.  */

    xh += xh;

  return ldbl_pack (xh, xl);

}

weak_alias (__roundevenl, roundevenl)