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allow.c revision 1.3 
      1 /*	$NetBSD: allow.c,v 1.3 1995/03/21 15:05:24 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)allow.c	8.1 (Berkeley) 5/31/93";
     39 #else
     40 static char rcsid[] = "$NetBSD: allow.c,v 1.3 1995/03/21 15:05:24 cgd Exp $";
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include "back.h"
     45 
     46 movallow ()  {
     47 
     48 	register int	i, m, iold;
     49 	int		r;
     50 
     51 	if (d0)
     52 		swap;
     53 	m = (D0 == D1? 4: 2);
     54 	for (i = 0; i < 4; i++)
     55 		p[i] = bar;
     56 	i = iold = 0;
     57 	while (i < m)  {
     58 		if (*offptr == 15)
     59 			break;
     60 		h[i] = 0;
     61 		if (board[bar])  {
     62 			if (i == 1 || m == 4)
     63 				g[i] = bar+cturn*D1;
     64 			else
     65 				g[i] = bar+cturn*D0;
     66 			if (r = makmove(i))  {
     67 				if (d0 || m == 4)
     68 					break;
     69 				swap;
     70 				movback (i);
     71 				if (i > iold)
     72 					iold = i;
     73 				for (i = 0; i < 4; i++)
     74 					p[i] = bar;
     75 				i = 0;
     76 			} else
     77 				i++;
     78 			continue;
     79 		}
     80 		if ((p[i] += cturn) == home)  {
     81 			if (i > iold)
     82 				iold = i;
     83 			if (m == 2 && i)  {
     84 				movback(i);
     85 				p[i--] = bar;
     86 				if (p[i] != bar)
     87 					continue;
     88 				else
     89 					break;
     90 			}
     91 			if (d0 || m == 4)
     92 				break;
     93 			swap;
     94 			movback (i);
     95 			for (i = 0; i < 4; i++)
     96 				p[i] = bar;
     97 			i = 0;
     98 			continue;
     99 		}
    100 		if (i == 1 || m == 4)
    101 			g[i] = p[i]+cturn*D1;
    102 		else
    103 			g[i] = p[i]+cturn*D0;
    104 		if (g[i]*cturn > home)  {
    105 			if (*offptr >= 0)
    106 				g[i] = home;
    107 			else
    108 				continue;
    109 		}
    110 		if (board[p[i]]*cturn > 0 && (r = makmove(i)) == 0)
    111 			i++;
    112 	}
    113 	movback (i);
    114 	return (iold > i? iold: i);
    115 }
    116