/* Round to integer type.  dbl-64 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 <errno.h>

#include <fenv.h>

#include <math.h>

#include <math_private.h>

#include <libm-alias-double.h>

#include <stdbool.h>

#include <stdint.h>

#define BIAS 0x3ff

#define MANT_DIG 53

#if UNSIGNED

# define RET_TYPE uintmax_t

#else

# define RET_TYPE intmax_t

#endif

#include <fromfp.h>

RET_TYPE

FUNC (double x, int round, unsigned int width)

{

  if (width > INTMAX_WIDTH)

    width = INTMAX_WIDTH;

  uint64_t ix;

  EXTRACT_WORDS64 (ix, x);

  bool negative = (ix & 0x8000000000000000ULL) != 0;

  if (width == 0)

    return fromfp_domain_error (negative, width);

  ix &= 0x7fffffffffffffffULL;

  if (ix == 0)

    return 0;

  int exponent = ix >> (MANT_DIG - 1);

  exponent -= BIAS;

  int max_exponent = fromfp_max_exponent (negative, width);

  if (exponent > max_exponent)

    return fromfp_domain_error (negative, width);

  ix &= ((1ULL << (MANT_DIG - 1)) - 1);

  ix |= 1ULL << (MANT_DIG - 1);

  uintmax_t uret;

  bool half_bit, more_bits;

  if (exponent >= MANT_DIG - 1)

    {

      uret = ix;

      uret <<= exponent - (MANT_DIG - 1);

      half_bit = false;

      more_bits = false;

    }

  else if (exponent >= -1)

    {

      uint64_t h = 1ULL << (MANT_DIG - 2 - exponent);

      half_bit = (ix & h) != 0;

      more_bits = (ix & (h - 1)) != 0;

      uret = ix >> (MANT_DIG - 1 - exponent);

    }

  else

    {

      uret = 0;

      half_bit = false;

      more_bits = true;

    }

  return fromfp_round_and_return (negative, uret, half_bit, more_bits, round,

				  exponent, max_exponent, width);

}