/* mpz_fdiv_q_ui -- Division rounding the quotient towards -infinity.

   The remainder gets the same sign as the denominator.

Copyright 1994-1996, 1999, 2001, 2002, 2004, 2012 Free Software Foundation,

Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify

it under the terms of either:

  * the GNU Lesser General Public License as published by the Free

    Software Foundation; either version 3 of the License, or (at your

    option) any later version.

or

  * the GNU General Public License as published by the Free Software

    Foundation; either version 2 of the License, or (at your option) any

    later version.

or both in parallel, as here.

The GNU MP 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 General Public License

for more details.

You should have received copies of the GNU General Public License and the

GNU Lesser General Public License along with the GNU MP Library.  If not,

see https://www.gnu.org/licenses/.  */

#include "gmp.h"

#include "gmp-impl.h"

unsigned long int

mpz_fdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor)

{

  mp_size_t ns, nn, qn;

  mp_ptr np, qp;

  mp_limb_t rl;

  if (UNLIKELY (divisor == 0))

    DIVIDE_BY_ZERO;

  ns = SIZ(dividend);

  if (ns == 0)

    {

      SIZ(quot) = 0;

      return 0;

    }

  nn = ABS(ns);

  qp = MPZ_REALLOC (quot, nn);

  np = PTR(dividend);

#if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */

  if (divisor > GMP_NUMB_MAX)

    {

      mp_limb_t dp[2], rp[2];

      if (nn == 1)		/* tdiv_qr requirements; tested above for 0 */

	{

	  qp[0] = 0;

	  rl = np[0];

	  qn = 1;		/* a white lie, fixed below */

	}

      else

	{

	  dp[0] = divisor & GMP_NUMB_MASK;

	  dp[1] = divisor >> GMP_NUMB_BITS;

	  mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);

	  rl = rp[0] + (rp[1] << GMP_NUMB_BITS);

	  qn = nn - 2 + 1;

	}

      if (rl != 0 && ns < 0)

	{

	  mpn_incr_u (qp, (mp_limb_t) 1);

	  rl = divisor - rl;

	}

      qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;

    }

  else

#endif

    {

      rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);

      if (rl != 0 && ns < 0)

	{

	  mpn_incr_u (qp, (mp_limb_t) 1);

	  rl = divisor - rl;

	}

      qn = nn - (qp[nn - 1] == 0);

    }

  SIZ(quot) = ns >= 0 ? qn : -qn;

  return rl;

}