BSD 4_3_Reno release

[unix-history] / usr / src / games / backgammon / common_source / allow.c

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement:  ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#ifndef lint
static char sccsid[] = "@(#)allow.c     5.4 (Berkeley) 6/1/90";
#endif /* not lint */

#include "back.h"

movallow ()  {

       register int    i, m, iold;
       int             r;

       if (d0)
               swap;
       m = (D0 == D1? 4: 2);
       for (i = 0; i < 4; i++)
               p[i] = bar;
       i = iold = 0;
       while (i < m)  {
               if (*offptr == 15)
                       break;
               h[i] = 0;
               if (board[bar])  {
                       if (i == 1 || m == 4)
                               g[i] = bar+cturn*D1;
                       else
                               g[i] = bar+cturn*D0;
                       if (r = makmove(i))  {
                               if (d0 || m == 4)
                                       break;
                               swap;
                               movback (i);
                               if (i > iold)
                                       iold = i;
                               for (i = 0; i < 4; i++)
                                       p[i] = bar;
                               i = 0;
                       } else
                               i++;
                       continue;
               }
               if ((p[i] += cturn) == home)  {
                       if (i > iold)
                               iold = i;
                       if (m == 2 && i)  {
                               movback(i);
                               p[i--] = bar;
                               if (p[i] != bar)
                                       continue;
                               else
                                       break;
                       }
                       if (d0 || m == 4)
                               break;
                       swap;
                       movback (i);
                       for (i = 0; i < 4; i++)
                               p[i] = bar;
                       i = 0;
                       continue;
               }
               if (i == 1 || m == 4)
                       g[i] = p[i]+cturn*D1;
               else
                       g[i] = p[i]+cturn*D0;
               if (g[i]*cturn > home)  {
                       if (*offptr >= 0)
                               g[i] = home;
                       else
                               continue;
               }
               if (board[p[i]]*cturn > 0 && (r = makmove(i)) == 0)
                       i++;
       }
       movback (i);
       return (iold > i? iold: i);
}