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Diff for /OpenXM_contrib/gmp/mpf/Attic/set_q.c between version 1.1 and 1.1.1.2

version 1.1, 2000/01/10 15:35:22 version 1.1.1.2, 2000/09/09 14:13:08
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 /* mpf_set_q (mpf_t rop, mpq_t op) -- Convert the rational op to the float rop.  /* mpf_set_q (mpf_t rop, mpq_t op) -- Convert the rational op to the float rop.
   
 Copyright (C) 1996 Free Software Foundation, Inc.  Copyright (C) 1996, 1999 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 23  MA 02111-1307, USA. */
Line 23  MA 02111-1307, USA. */
 #include "gmp-impl.h"  #include "gmp-impl.h"
 #include "longlong.h"  #include "longlong.h"
   
 /* Algorithm:  
    1. Develop >= n bits of src.num / src.den, where n is the number of bits  
       in a double.  This (partial) division will use all bits from the  
       denominator.  
    2. Use the remainder to determine how to round the result.  
    3. Assign the integral result to a temporary double.  
    4. Scale the temporary double, and return the result.  
   
    An alternative algorithm, that would be faster:  
    0. Let n be somewhat larger than the number of significant bits in a double.  
    1. Extract the most significant n bits of the denominator, and an equal  
       number of bits from the numerator.  
    2. Interpret the extracted numbers as integers, call them a and b  
       respectively, and develop n bits of the fractions ((a + 1) / b) and  
       (a / (b + 1)) using mpn_divrem.  
    3. If the computed values are identical UP TO THE POSITION WE CARE ABOUT,  
       we are done.  If they are different, repeat the algorithm from step 1,  
       but first let n = n * 2.  
    4. If we end up using all bits from the numerator and denominator, fall  
       back to the first algorithm above.  
    5. Just to make life harder, The computation of a + 1 and b + 1 above  
       might give carry-out...  Needs special handling.  It might work to  
       subtract 1 in both cases instead.  
 */  
   
 void  void
 #if __STDC__  #if __STDC__
 mpf_set_q (mpf_t r, mpq_srcptr q)  mpf_set_q (mpf_t r, mpq_srcptr q)
Line 132  mpf_set_q (r, q)
Line 107  mpf_set_q (r, q)
         }          }
       else        else
         {          {
           nlimb = mpn_lshift (rp, np, nsize, normalization_steps);            nlimb = mpn_lshift (rp, np, rsize, normalization_steps);
         }          }
       if (nlimb != 0)        if (nlimb != 0)
         {          {
           rp[rsize] = nlimb;            rp[rsize] = nlimb;
           rsize++;  
           exp++;            exp++;
             /* Don't just increase rsize, chop off rp at the low end instead.  */
             if (rsize == prec)
               rp++;
             else
               rsize++;
         }          }
     }      }
   else    else
Line 164  mpf_set_q (r, q)
Line 143  mpf_set_q (r, q)
     }      }
   
   EXP (r) = exp;    EXP (r) = exp;
   SIZ (r) = qsize;    SIZ (r) = sign_quotient >= 0 ? qsize : -qsize;
   
   TMP_FREE (marker);    TMP_FREE (marker);
 }  }
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