/* mpn_rshift -- Shift right a low-level natural-number integer. Copyright (C) 1991, 1993, 1994, 1996 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 modifyit under the terms of the GNU Lesser General Public License as published bythe Free Software Foundation; either version 2.1 of the License, or (at youroption) any later version. The GNU MP Library is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITYor FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General PublicLicense for more details. You should have received a copy of the GNU Lesser General Public Licensealong with the GNU MP Library; see the file COPYING.LIB.  If not, write tothe Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,MA 02111-1307, USA. */ #include <config.h>#include "gmp-impl.h" /* Shift U (pointed to by UP and USIZE limbs long) CNT bits to the right   and store the USIZE least significant limbs of the result at WP.   The bits shifted out to the right are returned.    Argument constraints:   1. 0 < CNT < BITS_PER_MP_LIMB   2. If the result is to be written over the input, WP must be <= UP.*/ mp_limb_t#if __STDC__mpn_rshift (register mp_ptr wp,	    register mp_srcptr up, mp_size_t usize,	    register unsigned int cnt)#elsempn_rshift (wp, up, usize, cnt)     register mp_ptr wp;     register mp_srcptr up;     mp_size_t usize;     register unsigned int cnt;#endif{  register mp_limb_t high_limb, low_limb;  register unsigned sh_1, sh_2;  register mp_size_t i;  mp_limb_t retval; #ifdef DEBUG  if (usize == 0 || cnt == 0)    abort ();#endif   sh_1 = cnt; #if 0  if (sh_1 == 0)    {      if (wp != up)	{	  /* Copy from low end to high end, to allow specified input/output	     overlapping.  */	  for (i = 0; i < usize; i++)	    wp[i] = up[i];	}      return usize;    }#endif   wp -= 1;  sh_2 = BITS_PER_MP_LIMB - sh_1;  high_limb = up[0];  retval = high_limb << sh_2;  low_limb = high_limb;   for (i = 1; i < usize; i++)    {      high_limb = up[i];      wp[i] = (low_limb >> sh_1) | (high_limb << sh_2);      low_limb = high_limb;    }  wp[i] = low_limb >> sh_1;   return retval;}