/* Round double value to long int.

   Copyright (C) 1997-2018 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, see

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

#include <fenv.h>

#include <limits.h>

#include <math.h>

#include <math_private.h>

#include <libm-alias-double.h>

#include <fix-fp-int-convert-overflow.h>

long int

__lround (double x)

{

  int32_t j0;

  uint32_t i1, i0;

  long int result;

  int sign;

  EXTRACT_WORDS (i0, i1, x);

  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;

  sign = (i0 & 0x80000000) != 0 ? -1 : 1;

  i0 &= 0xfffff;

  i0 |= 0x100000;

  if (j0 < 20)

    {

      if (j0 < 0)

	return j0 < -1 ? 0 : sign;

      else

	{

	  i0 += 0x80000 >> j0;

	  result = i0 >> (20 - j0);

	}

    }

  else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)

    {

      if (j0 >= 52)

	result = ((long int) i0 << (j0 - 20)) | ((long int) i1 << (j0 - 52));

      else

	{

	  uint32_t j = i1 + (0x80000000 >> (j0 - 20));

	  if (j < i1)

	    ++i0;

	  if (j0 == 20)

	    result = (long int) i0;

	  else

	    {

	      result = ((long int) i0 << (j0 - 20)) | (j >> (52 - j0));

#ifdef FE_INVALID

	      if (sizeof (long int) == 4

		  && sign == 1

		  && result == LONG_MIN)

		/* Rounding brought the value out of range.  */

		feraiseexcept (FE_INVALID);

#endif

	    }

	}

    }

  else

    {

      /* The number is too large.  Unless it rounds to LONG_MIN,

	 FE_INVALID must be raised and the return value is

	 unspecified.  */

#ifdef FE_INVALID

      if (FIX_DBL_LONG_CONVERT_OVERFLOW

	  && !(sign == -1

	       && (sizeof (long int) == 4

		   ? x > (double) LONG_MIN - 0.5

		   : x >= (double) LONG_MIN)))

	{

	  feraiseexcept (FE_INVALID);

	  return sign == 1 ? LONG_MAX : LONG_MIN;

	}

      else if (!FIX_DBL_LONG_CONVERT_OVERFLOW

	       && sizeof (long int) == 4

	       && x <= (double) LONG_MIN - 0.5)

	{

	  /* If truncation produces LONG_MIN, the cast will not raise

	     the exception, but may raise "inexact".  */

	  feraiseexcept (FE_INVALID);

	  return LONG_MIN;

	}

#endif

      return (long int) x;

    }

  return sign * result;

}

libm_alias_double (__lround, lround)