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Diff for /OpenXM_contrib/gmp/mpn/generic/Attic/divrem.c between version 1.1 and 1.1.1.3

version 1.1, 2000/01/10 15:35:23 version 1.1.1.3, 2003/08/25 16:06:20
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 /* mpn_divrem -- Divide natural numbers, producing both remainder and  /* mpn_divrem -- Divide natural numbers, producing both remainder and
    quotient.     quotient.  This is now just a middle layer for calling the new
      internal mpn_tdiv_qr.
   
 Copyright (C) 1993, 1994, 1995, 1996 Free Software Foundation, Inc.  Copyright 1993, 1994, 1995, 1996, 1997, 1999, 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.
   
 The GNU MP Library is free software; you can redistribute it and/or modify  The GNU MP Library is free software; you can redistribute it and/or modify
 it under the terms of the GNU Library General Public License as published by  it under the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation; either version 2 of the License, or (at your  the Free Software Foundation; either version 2.1 of the License, or (at your
 option) any later version.  option) any later version.
   
 The GNU MP Library is distributed in the hope that it will be useful, but  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  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 License for more details.  License for more details.
   
 You should have received a copy of the GNU Library General Public License  You should have received a copy of the GNU Lesser General Public License
 along with the GNU MP Library; see the file COPYING.LIB.  If not, write to  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 MA 02111-1307, USA. */  MA 02111-1307, USA. */
Line 24  MA 02111-1307, USA. */
Line 26  MA 02111-1307, USA. */
 #include "gmp-impl.h"  #include "gmp-impl.h"
 #include "longlong.h"  #include "longlong.h"
   
 /* Divide num (NP/NSIZE) by den (DP/DSIZE) and write  
    the NSIZE-DSIZE least significant quotient limbs at QP  
    and the DSIZE long remainder at NP.  If QEXTRA_LIMBS is  
    non-zero, generate that many fraction bits and append them after the  
    other quotient limbs.  
    Return the most significant limb of the quotient, this is always 0 or 1.  
   
    Preconditions:  
    0. NSIZE >= DSIZE.  
    1. The most significant bit of the divisor must be set.  
    2. QP must either not overlap with the input operands at all, or  
       QP + DSIZE >= NP must hold true.  (This means that it's  
       possible to put the quotient in the high part of NUM, right after the  
       remainder in NUM.  
    3. NSIZE >= DSIZE, even if QEXTRA_LIMBS is non-zero.  */  
   
 mp_limb_t  mp_limb_t
 #if __STDC__  mpn_divrem (mp_ptr qp, mp_size_t qxn,
 mpn_divrem (mp_ptr qp, mp_size_t qextra_limbs,              mp_ptr np, mp_size_t nn,
             mp_ptr np, mp_size_t nsize,              mp_srcptr dp, mp_size_t dn)
             mp_srcptr dp, mp_size_t dsize)  
 #else  
 mpn_divrem (qp, qextra_limbs, np, nsize, dp, dsize)  
      mp_ptr qp;  
      mp_size_t qextra_limbs;  
      mp_ptr np;  
      mp_size_t nsize;  
      mp_srcptr dp;  
      mp_size_t dsize;  
 #endif  
 {  {
   mp_limb_t most_significant_q_limb = 0;    ASSERT (qxn >= 0);
     ASSERT (nn >= dn);
     ASSERT (dn >= 1);
     ASSERT (dp[dn-1] & GMP_NUMB_HIGHBIT);
     ASSERT (! MPN_OVERLAP_P (np, nn, dp, dn));
     ASSERT (! MPN_OVERLAP_P (qp, nn-dn+qxn, np, nn) || qp==np+dn+qxn);
     ASSERT (! MPN_OVERLAP_P (qp, nn-dn+qxn, dp, dn));
     ASSERT_MPN (np, nn);
     ASSERT_MPN (dp, dn);
   
   switch (dsize)    if (dn == 1)
     {      {
     case 0:        mp_limb_t ret;
       /* We are asked to divide by zero, so go ahead and do it!  (To make        mp_ptr q2p;
          the compiler not remove this statement, return the value.)  */        mp_size_t qn;
       return 1 / dsize;        TMP_DECL (marker);
   
     case 1:        TMP_MARK (marker);
       {        q2p = (mp_ptr) TMP_ALLOC ((nn + qxn) * BYTES_PER_MP_LIMB);
         mp_size_t i;  
         mp_limb_t n1;  
         mp_limb_t d;  
   
         d = dp[0];        np[0] = mpn_divrem_1 (q2p, qxn, np, nn, dp[0]);
         n1 = np[nsize - 1];        qn = nn + qxn - 1;
         MPN_COPY (qp, q2p, qn);
         ret = q2p[qn];
   
         if (n1 >= d)        TMP_FREE (marker);
           {        return ret;
             n1 -= d;  
             most_significant_q_limb = 1;  
           }  
   
         qp += qextra_limbs;  
         for (i = nsize - 2; i >= 0; i--)  
           udiv_qrnnd (qp[i], n1, n1, np[i], d);  
         qp -= qextra_limbs;  
   
         for (i = qextra_limbs - 1; i >= 0; i--)  
           udiv_qrnnd (qp[i], n1, n1, 0, d);  
   
         np[0] = n1;  
       }  
       break;  
   
     case 2:  
       {  
         mp_size_t i;  
         mp_limb_t n1, n0, n2;  
         mp_limb_t d1, d0;  
   
         np += nsize - 2;  
         d1 = dp[1];  
         d0 = dp[0];  
         n1 = np[1];  
         n0 = np[0];  
   
         if (n1 >= d1 && (n1 > d1 || n0 >= d0))  
           {  
             sub_ddmmss (n1, n0, n1, n0, d1, d0);  
             most_significant_q_limb = 1;  
           }  
   
         for (i = qextra_limbs + nsize - 2 - 1; i >= 0; i--)  
           {  
             mp_limb_t q;  
             mp_limb_t r;  
   
             if (i >= qextra_limbs)  
               np--;  
             else  
               np[0] = 0;  
   
             if (n1 == d1)  
               {  
                 /* Q should be either 111..111 or 111..110.  Need special  
                    treatment of this rare case as normal division would  
                    give overflow.  */  
                 q = ~(mp_limb_t) 0;  
   
                 r = n0 + d1;  
                 if (r < d1)     /* Carry in the addition? */  
                   {  
                     add_ssaaaa (n1, n0, r - d0, np[0], 0, d0);  
                     qp[i] = q;  
                     continue;  
                   }  
                 n1 = d0 - (d0 != 0);  
                 n0 = -d0;  
               }  
             else  
               {  
                 udiv_qrnnd (q, r, n1, n0, d1);  
                 umul_ppmm (n1, n0, d0, q);  
               }  
   
             n2 = np[0];  
           q_test:  
             if (n1 > r || (n1 == r && n0 > n2))  
               {  
                 /* The estimated Q was too large.  */  
                 q--;  
   
                 sub_ddmmss (n1, n0, n1, n0, 0, d0);  
                 r += d1;  
                 if (r >= d1)    /* If not carry, test Q again.  */  
                   goto q_test;  
               }  
   
             qp[i] = q;  
             sub_ddmmss (n1, n0, r, n2, n1, n0);  
           }  
         np[1] = n1;  
         np[0] = n0;  
       }  
       break;  
   
     default:  
       {  
         mp_size_t i;  
         mp_limb_t dX, d1, n0;  
   
         np += nsize - dsize;  
         dX = dp[dsize - 1];  
         d1 = dp[dsize - 2];  
         n0 = np[dsize - 1];  
   
         if (n0 >= dX)  
           {  
             if (n0 > dX || mpn_cmp (np, dp, dsize - 1) >= 0)  
               {  
                 mpn_sub_n (np, np, dp, dsize);  
                 n0 = np[dsize - 1];  
                 most_significant_q_limb = 1;  
               }  
           }  
   
         for (i = qextra_limbs + nsize - dsize - 1; i >= 0; i--)  
           {  
             mp_limb_t q;  
             mp_limb_t n1, n2;  
             mp_limb_t cy_limb;  
   
             if (i >= qextra_limbs)  
               {  
                 np--;  
                 n2 = np[dsize];  
               }  
             else  
               {  
                 n2 = np[dsize - 1];  
                 MPN_COPY_DECR (np + 1, np, dsize);  
                 np[0] = 0;  
               }  
   
             if (n0 == dX)  
               /* This might over-estimate q, but it's probably not worth  
                  the extra code here to find out.  */  
               q = ~(mp_limb_t) 0;  
             else  
               {  
                 mp_limb_t r;  
   
                 udiv_qrnnd (q, r, n0, np[dsize - 1], dX);  
                 umul_ppmm (n1, n0, d1, q);  
   
                 while (n1 > r || (n1 == r && n0 > np[dsize - 2]))  
                   {  
                     q--;  
                     r += dX;  
                     if (r < dX) /* I.e. "carry in previous addition?"  */  
                       break;  
                     n1 -= n0 < d1;  
                     n0 -= d1;  
                   }  
               }  
   
             /* Possible optimization: We already have (q * n0) and (1 * n1)  
                after the calculation of q.  Taking advantage of that, we  
                could make this loop make two iterations less.  */  
   
             cy_limb = mpn_submul_1 (np, dp, dsize, q);  
   
             if (n2 != cy_limb)  
               {  
                 mpn_add_n (np, np, dp, dsize);  
                 q--;  
               }  
   
             qp[i] = q;  
             n0 = np[dsize - 1];  
           }  
       }  
     }      }
     else if (dn == 2)
       {
         return mpn_divrem_2 (qp, qxn, np, nn, dp);
       }
     else
       {
         mp_ptr rp, q2p;
         mp_limb_t qhl;
         mp_size_t qn;
         TMP_DECL (marker);
   
   return most_significant_q_limb;        TMP_MARK (marker);
         if (qxn != 0)
           {
             mp_ptr n2p;
             n2p = (mp_ptr) TMP_ALLOC ((nn + qxn) * BYTES_PER_MP_LIMB);
             MPN_ZERO (n2p, qxn);
             MPN_COPY (n2p + qxn, np, nn);
             q2p = (mp_ptr) TMP_ALLOC ((nn - dn + qxn + 1) * BYTES_PER_MP_LIMB);
             rp = (mp_ptr) TMP_ALLOC (dn * BYTES_PER_MP_LIMB);
             mpn_tdiv_qr (q2p, rp, 0L, n2p, nn + qxn, dp, dn);
             MPN_COPY (np, rp, dn);
             qn = nn - dn + qxn;
             MPN_COPY (qp, q2p, qn);
             qhl = q2p[qn];
           }
         else
           {
             q2p = (mp_ptr) TMP_ALLOC ((nn - dn + 1) * BYTES_PER_MP_LIMB);
             rp = (mp_ptr) TMP_ALLOC (dn * BYTES_PER_MP_LIMB);
             mpn_tdiv_qr (q2p, rp, 0L, np, nn, dp, dn);
             MPN_COPY (np, rp, dn);        /* overwrite np area with remainder */
             qn = nn - dn;
             MPN_COPY (qp, q2p, qn);
             qhl = q2p[qn];
           }
         TMP_FREE (marker);
         return qhl;
       }
 }  }
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