text: /*  mpn_divexact_byff
  
  dnl  Copyright 2009 Jason Moxham
  
  dnl  This file is part of the MPIR Library.
  
  dnl  The MPIR Library is free software; you can redistribute it and/or modify
  dnl  it under the terms of the GNU Lesser General Public License as published
  dnl  by the Free Software Foundation; either version 2.1 of the License, or (at
  dnl  your option) any later version.
  
  dnl  The MPIR Library is distributed in the hope that it will be useful, but
  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  dnl  License for more details.
  
  dnl  You should have received a copy of the GNU Lesser General Public License
  dnl  along with the MPIR Library; see the file COPYING.LIB.  If not, write
  dnl  to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  dnl  Boston, MA 02110-1301, USA.
  
  */
  
  #include "mpir.h"
  #include "gmp-impl.h"
  
  /*
  	Where (xp,n) = (qp, n)*(B - 1) - ret*B^n and 0 <= ret < B - 1, B = 2^GMP_NUMB_BITS
  	
  	This is the standard divexact algorithm with simplifications for the divisior B-1
  */
  mp_limb_t
  mpn_divexact_byff (mp_ptr qp, mp_srcptr xp, mp_size_t n)
  {
    mp_size_t j;
    mp_limb_t t, a, b;
  
    ASSERT (n > 0);
    ASSERT_MPN (xp, n);
    ASSERT (MPN_SAME_OR_SEPARATE_P (qp, xp, n));
  
    a = 0;
    for (j = 0; j <= n - 1; j++)
      {
        t = xp[j];
        if (t > a)
  	{
  	  b = 1;
  	}
        else
  	{
  	  b = 0;
  	}
        a = a - t;
        qp[j] = a;
        a = a - b;		/* no borrow from this sub */
      }
    return a;
  }
  