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Diff for /OpenXM_contrib/gmp/mpn/generic/Attic/rshift.c between version 1.1.1.2 and 1.1.1.3

version 1.1.1.2, 2000/09/09 14:12:27 version 1.1.1.3, 2003/08/25 16:06:20
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 /* mpn_rshift -- Shift right a low-level natural-number integer.  /* mpn_rshift -- Shift right low level.
   
 Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.  Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2002 Free Software Foundation,
   Inc.
   
 This file is part of the GNU MP Library.  This file is part of the GNU MP Library.
   
Line 22  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
 #include "gmp.h"  #include "gmp.h"
 #include "gmp-impl.h"  #include "gmp-impl.h"
   
 /* Shift U (pointed to by UP and USIZE limbs long) CNT bits to the right  /* Shift U (pointed to by up and N limbs long) cnt bits to the right
    and store the USIZE least significant limbs of the result at WP.     and store the n least significant limbs of the result at rp.
    The bits shifted out to the right are returned.     The bits shifted out to the right are returned.
   
    Argument constraints:     Argument constraints:
    1. 0 < CNT < BITS_PER_MP_LIMB     1. 0 < cnt < GMP_NUMB_BITS.
    2. If the result is to be written over the input, WP must be <= UP.     2. If the result is to be written over the input, rp must be <= up.
 */  */
   
 mp_limb_t  mp_limb_t
 #if __STDC__  mpn_rshift (mp_ptr rp, mp_srcptr up, mp_size_t n, unsigned int cnt)
 mpn_rshift (register mp_ptr wp,  
             register mp_srcptr up, mp_size_t usize,  
             register unsigned int cnt)  
 #else  
 mpn_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;    mp_limb_t high_limb, low_limb;
   register unsigned sh_1, sh_2;    unsigned int tnc;
   register mp_size_t i;    mp_size_t i;
   mp_limb_t retval;    mp_limb_t retval;
   
 #ifdef DEBUG    ASSERT (n >= 1);
   if (usize == 0 || cnt == 0)    ASSERT (cnt >= 1);
     abort ();    ASSERT (cnt < GMP_NUMB_BITS);
 #endif    ASSERT (MPN_SAME_OR_INCR_P (rp, up, n));
   
   sh_1 = cnt;    tnc = GMP_NUMB_BITS - cnt;
     high_limb = *up++;
     retval = (high_limb << tnc) & GMP_NUMB_MASK;
     low_limb = high_limb >> cnt;
   
 #if 0    for (i = n - 1; i != 0; i--)
   if (sh_1 == 0)  
     {      {
       if (wp != up)        high_limb = *up++;
         {        *rp++ = low_limb | ((high_limb << tnc) & GMP_NUMB_MASK);
           /* Copy from low end to high end, to allow specified input/output        low_limb = high_limb >> cnt;
              overlapping.  */  
           for (i = 0; i < usize; i++)  
             wp[i] = up[i];  
         }  
       return usize;  
     }      }
 #endif    *rp = low_limb;
   
   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;    return retval;
 }  }
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  Added in v.1.1.1.3
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