/* mpi-bit.c  -  MPI bit level fucntions
   * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   *
   * This file is part of GnuPG.
   *
   * GnuPG is free software; you can redistribute it and/or modify
   * it under the terms of 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.
   *
   * GnuPG 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 a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
   */
  
  #include "mpi-internal.h"
  #include "longlong.h"
  
  #define A_LIMB_1 ((mpi_limb_t) 1)
  
  /****************
   * Sometimes we have MSL (most significant limbs) which are 0;
   * this is for some reasons not good, so this function removes them.
   */
  void mpi_normalize(MPI a)
  {
  	for (; a->nlimbs && !a->d[a->nlimbs - 1]; a->nlimbs--)
  		;
  }
  
  /****************
   * Return the number of bits in A.
   */
  unsigned mpi_get_nbits(MPI a)
  {
  	unsigned n;
  
  	mpi_normalize(a);
  
  	if (a->nlimbs) {
  		mpi_limb_t alimb = a->d[a->nlimbs - 1];
  		if (alimb)
  			n = count_leading_zeros(alimb);
  		else
  			n = BITS_PER_MPI_LIMB;
  		n = BITS_PER_MPI_LIMB - n + (a->nlimbs - 1) * BITS_PER_MPI_LIMB;
  	} else
  		n = 0;
  	return n;
  }
  EXPORT_SYMBOL_GPL(mpi_get_nbits);