/* mpn_bdiv_q_1, mpn_pi1_bdiv_q_1 -- schoolbook Hensel division by 1-limb

   divisor, returning quotient only.

   THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY.  THEY'RE ALMOST

   CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN

   FUTURE GNU MP RELEASES.

Copyright 2000-2003, 2005, 2009 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"

#include "longlong.h"

mp_limb_t

mpn_pi1_bdiv_q_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t d,

		  mp_limb_t di, int shift)

{

  mp_size_t  i;

  mp_limb_t  c, h, l, u, u_next, dummy;

  ASSERT (n >= 1);

  ASSERT (d != 0);

  ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));

  ASSERT_MPN (up, n);

  ASSERT_LIMB (d);

  d <<= GMP_NAIL_BITS;

  if (shift != 0)

    {

      c = 0;

      u = up[0];

      rp--;

      for (i = 1; i < n; i++)

	{

	  u_next = up[i];

	  u = ((u >> shift) | (u_next << (GMP_NUMB_BITS-shift))) & GMP_NUMB_MASK;

	  SUBC_LIMB (c, l, u, c);

	  l = (l * di) & GMP_NUMB_MASK;

	  rp[i] = l;

	  umul_ppmm (h, dummy, l, d);

	  c += h;

	  u = u_next;

	}

      u = u >> shift;

      l = u - c;

      l = (l * di) & GMP_NUMB_MASK;

      rp[i] = l;

    }

  else

    {

      u = up[0];

      l = (u * di) & GMP_NUMB_MASK;

      rp[0] = l;

      c = 0;

      for (i = 1; i < n; i++)

	{

	  umul_ppmm (h, dummy, l, d);

	  c += h;

	  u = up[i];

	  SUBC_LIMB (c, l, u, c);

	  l = (l * di) & GMP_NUMB_MASK;

	  rp[i] = l;

	}

    }

  return c;

}

mp_limb_t

mpn_bdiv_q_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t d)

{

  mp_limb_t di;

  int shift;

  ASSERT (n >= 1);

  ASSERT (d != 0);

  ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));

  ASSERT_MPN (up, n);

  ASSERT_LIMB (d);

  if ((d & 1) == 0)

    {

      count_trailing_zeros (shift, d);

      d >>= shift;

    }

  else

    shift = 0;

  binvert_limb (di, d);

  return mpn_pi1_bdiv_q_1 (rp, up, n, d, di, shift);

}