/* Round double value to long long int.

   Copyright (C) 1997-2018 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 <limits.h>

#include <math.h>

#include <math_ldbl_opt.h>

#include <math_private.h>

#include <stdint.h>

#include <libm-alias-double.h>

/* Round to the nearest integer, with values exactly on a 0.5 boundary

   rounded away from zero, regardless of the current rounding mode.

   If (long long)x, when x is out of range of a long long, clips at

   LLONG_MAX or LLONG_MIN, then this implementation also clips.  */

long long int

__llround (double x)

{

  long long xr;

  if (HAVE_PPC_FCTIDZ)

    xr = (long long) x;

  else

    {

      /* Avoid incorrect exceptions from libgcc conversions (as of GCC

	 5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>.  */

      if (fabs (x) < 0x1p31)

	xr = (long long int) (long int) x;

      else

	{

	  uint64_t i0;

	  EXTRACT_WORDS64 (i0, x);

	  int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff;

	  if (exponent < 63)

	    {

	      unsigned long long int mant

		= (i0 & ((1ULL << 52) - 1)) | (1ULL << 52);

	      if (exponent < 52)

		/* llround is not required to raise "inexact".  */

		mant >>= 52 - exponent;

	      else

		mant <<= exponent - 52;

	      xr = (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant);

	    }

	  else if (x == (double) LLONG_MIN)

	    xr = LLONG_MIN;

	  else

	    xr = (long long int) (long int) x << 32;

	}

    }

  /* Avoid spurious "inexact" converting LLONG_MAX to double, and from

     subtraction when the result is out of range, by returning early

     for arguments large enough that no rounding is needed.  */

  if (!(fabs (x) < 0x1p52))

    return xr;

  double xrf = (double) xr;

  if (x >= 0.0)

    {

      if (x - xrf >= 0.5)

	xr += (long long) ((unsigned long long) xr + 1) > 0;

    }

  else

    {

      if (xrf - x >= 0.5)

	xr -= (long long) ((unsigned long long) xr - 1) < 0;

    }

  return xr;

}

libm_alias_double (__llround, llround)