"Fossies" - the Fresh Open Source Software Archive

Member "mapm_4.9.5a/mapmipwr.c" (21 Feb 2010, 2674 Bytes) of package /linux/misc/old/mapm-4.9.5a.tar.gz:

    1 
    2 /* 
    3  *  M_APM  -  mapmipwr.c
    4  *
    5  *  Copyright (C) 1999 - 2007   Michael C. Ring
    6  *
    7  *  Permission to use, copy, and distribute this software and its
    8  *  documentation for any purpose with or without fee is hereby granted,
    9  *  provided that the above copyright notice appear in all copies and
   10  *  that both that copyright notice and this permission notice appear
   11  *  in supporting documentation.
   12  *
   13  *  Permission to modify the software is granted. Permission to distribute
   14  *  the modified code is granted. Modifications are to be distributed by
   15  *  using the file 'license.txt' as a template to modify the file header.
   16  *  'license.txt' is available in the official MAPM distribution.
   17  *
   18  *  This software is provided "as is" without express or implied warranty.
   19  */
   20 
   21 /*
   22  *      $Id: mapmipwr.c,v 1.6 2007/12/03 01:54:39 mike Exp $
   23  *
   24  *      This file contains the Integer Power function.
   25  *
   26  *      $Log: mapmipwr.c,v $
   27  *      Revision 1.6  2007/12/03 01:54:39  mike
   28  *      Update license
   29  *
   30  *      Revision 1.5  2002/11/03 21:10:32  mike
   31  *      Updated function parameters to use the modern style
   32  *
   33  *      Revision 1.4  2000/09/23 19:46:04  mike
   34  *      change divide call to reciprocal
   35  *
   36  *      Revision 1.3  2000/05/24 17:03:35  mike
   37  *      return 1 when input is 0^0
   38  *
   39  *      Revision 1.2  1999/09/18 01:34:35  mike
   40  *      minor tweaks
   41  *
   42  *      Revision 1.1  1999/09/18 01:33:09  mike
   43  *      Initial revision
   44  */
   45 
   46 #include "m_apm_lc.h"
   47 
   48 /****************************************************************************/
   49 void    m_apm_integer_pow(M_APM rr, int places, M_APM aa, int mexp)
   50 {
   51 M_APM   tmp0, tmpy, tmpz;
   52 int nexp, ii, signflag, local_precision;
   53 
   54 if (mexp == 0)
   55   {
   56    m_apm_copy(rr, MM_One);
   57    return;
   58   }
   59 else
   60   {
   61    if (mexp > 0)
   62      {
   63       signflag = 0;
   64       nexp     = mexp;
   65      }
   66    else
   67      {
   68       signflag = 1;
   69       nexp     = -mexp;
   70      }
   71   }
   72 
   73 if (aa->m_apm_sign == 0)
   74   {
   75    M_set_to_zero(rr);
   76    return;
   77   }
   78 
   79 tmp0 = M_get_stack_var();
   80 tmpy = M_get_stack_var();
   81 tmpz = M_get_stack_var();
   82 
   83 local_precision = places + 8;
   84 
   85 m_apm_copy(tmpy, MM_One);
   86 m_apm_copy(tmpz, aa);
   87 
   88 while (TRUE)
   89   {
   90    ii   = nexp & 1;
   91    nexp = nexp >> 1;
   92 
   93    if (ii != 0)                       /* exponent -was- odd */
   94      {
   95       m_apm_multiply(tmp0, tmpy, tmpz);
   96       m_apm_round(tmpy, local_precision, tmp0);
   97 
   98       if (nexp == 0)
   99         break;
  100      }
  101 
  102    m_apm_multiply(tmp0, tmpz, tmpz);
  103    m_apm_round(tmpz, local_precision, tmp0);
  104   }
  105 
  106 if (signflag)
  107   {
  108    m_apm_reciprocal(rr, places, tmpy);
  109   }
  110 else
  111   {
  112    m_apm_round(rr, places, tmpy);
  113   }
  114 
  115 M_restore_stack(3);
  116 }
  117 /****************************************************************************/