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Diff for /OpenXM_contrib/gmp/mpz/Attic/divexact.c between version 1.1.1.1 and 1.1.1.2

version 1.1.1.1, 2000/01/10 15:35:27 version 1.1.1.2, 2000/09/09 14:12:50
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 /* mpz_divexact -- finds quotient when known that quot * den == num && den != 0.  /* mpz_divexact -- finds quotient when known that quot * den == num && den != 0.
   
 Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.  Copyright (C) 1991, 1993, 1994, 1995, 1996, 1997, 1998, 2000 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 27  MA 02111-1307, USA.  */
Line 28  MA 02111-1307, USA.  */
     de Matema'tica at Universidade Federal do Rio Grande do Sul (UFRGS).      de Matema'tica at Universidade Federal do Rio Grande do Sul (UFRGS).
   
     References:      References:
         T. Jebelean, An algorithm for exact division, Journal of Symbolic          T. Jebelean, An algorithm for exact division, Journal of Symbolic
         Computation, v. 15, 1993, pp. 169-180.  */          Computation, v. 15, 1993, pp. 169-180.  */
   
 #include "gmp.h"  #include "gmp.h"
 #include "gmp-impl.h"  #include "gmp-impl.h"
Line 46  mpz_divexact (quot, num, den)
Line 47  mpz_divexact (quot, num, den)
 {  {
   mp_ptr qp, tp;    mp_ptr qp, tp;
   mp_size_t qsize, tsize;    mp_size_t qsize, tsize;
     mp_srcptr np, dp;
   mp_srcptr np = num->_mp_d;    mp_size_t nsize, dsize;
   mp_srcptr dp = den->_mp_d;  
   mp_size_t nsize = ABS (num->_mp_size);  
   mp_size_t dsize = ABS (den->_mp_size);  
   TMP_DECL (marker);    TMP_DECL (marker);
   
   /*  Generate divide-by-zero error if dsize == 0.  */    nsize = ABS (num->_mp_size);
   if (dsize == 0)    dsize = ABS (den->_mp_size);
     {  
       quot->_mp_size = 1 / dsize;  
       return;  
     }  
   
     qsize = nsize - dsize + 1;
     if (quot->_mp_alloc < qsize)
       _mpz_realloc (quot, qsize);
   
     np = num->_mp_d;
     dp = den->_mp_d;
     qp = quot->_mp_d;
   
   if (nsize == 0)    if (nsize == 0)
     {      {
         if (dsize == 0)
           DIVIDE_BY_ZERO;
       quot->_mp_size = 0;        quot->_mp_size = 0;
       return;        return;
     }      }
   
   qsize = nsize - dsize + 1;    if (dsize <= 1)
   if (quot->_mp_alloc < qsize)      {
     _mpz_realloc (quot, qsize);        if (dsize == 1)
   qp = quot->_mp_d;          {
             mpn_divmod_1 (qp, np, nsize, dp[0]);
             qsize -= qp[qsize - 1] == 0;
             quot->_mp_size = (num->_mp_size ^ den->_mp_size) >= 0 ? qsize : -qsize;
             return;
           }
   
         /*  Generate divide-by-zero error since dsize == 0.  */
         DIVIDE_BY_ZERO;
       }
   
   TMP_MARK (marker);    TMP_MARK (marker);
   
   /*  QUOT <-- NUM/2^r, T <-- DEN/2^r where = r number of twos in DEN.  */    /*  QUOT <-- NUM/2^r, T <-- DEN/2^r where = r number of twos in DEN.  */
   while (dp[0] == 0)    while (dp[0] == 0)
     np += 1, nsize -= 1, dp += 1, dsize -= 1;      np += 1, nsize -= 1, dp += 1, dsize -= 1;
   tsize = MIN (qsize, dsize);    tsize = MIN (qsize, dsize);
   if (dp[0] & 1)    if ((dp[0] & 1) != 0)
     {      {
       if (qp != dp)        if (quot == den)          /*  QUOT and DEN overlap.  */
         MPN_COPY (qp, np, qsize);  
       if (qp == dp)             /*  QUOT and DEN overlap.  */  
         {          {
           tp = (mp_ptr) TMP_ALLOC (sizeof (mp_limb_t) * tsize);            tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
           MPN_COPY (tp, dp, tsize);            MPN_COPY (tp, dp, tsize);
         }          }
       else        else
         tp = (mp_ptr) dp;          tp = (mp_ptr) dp;
         if (qp != np)
           MPN_COPY_INCR (qp, np, qsize);
     }      }
   else    else
     {      {
       unsigned long int r;        unsigned int r;
       tp = (mp_ptr) TMP_ALLOC (sizeof (mp_limb_t) * tsize);        tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
       count_trailing_zeros (r, dp[0]);        count_trailing_zeros (r, dp[0]);
       mpn_rshift (tp, dp, tsize, r);        mpn_rshift (tp, dp, tsize, r);
       if (dsize > tsize)        if (dsize > tsize)
         tp[tsize-1] |= dp[tsize] << (BITS_PER_MP_LIMB - r);          tp[tsize - 1] |= dp[tsize] << (BITS_PER_MP_LIMB - r);
       mpn_rshift (qp, np, qsize, r);        mpn_rshift (qp, np, qsize, r);
       if (nsize > qsize)        if (nsize > qsize)
         qp[qsize-1] |= np[qsize] << (BITS_PER_MP_LIMB - r);          qp[qsize - 1] |= np[qsize] << (BITS_PER_MP_LIMB - r);
     }      }
   
   /*  Now QUOT <-- QUOT/T.  */    /*  Now QUOT <-- QUOT/T.  */
   mpn_bdivmod (qp, qp, qsize, tp, tsize, qsize * BITS_PER_MP_LIMB);    mpn_bdivmod (qp, qp, qsize, tp, tsize, qsize * BITS_PER_MP_LIMB);
   MPN_NORMALIZE (qp, qsize);    MPN_NORMALIZE (qp, qsize);
   
   quot->_mp_size = (num->_mp_size < 0) == (den->_mp_size < 0) ? qsize : -qsize;    quot->_mp_size = (num->_mp_size ^ den->_mp_size) >= 0 ? qsize : -qsize;
   
   TMP_FREE (marker);    TMP_FREE (marker);
 }  }
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