1 /* 2 * Copyright (c) 1980 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 static char sccsid[] = "@(#)allow.c 5.3 (Berkeley) 06/18/88"; 20 #endif /* not lint */ 21 22 #include "back.h" 23 24 movallow () { 25 26 register int i, m, iold; 27 int r; 28 29 if (d0) 30 swap; 31 m = (D0 == D1? 4: 2); 32 for (i = 0; i < 4; i++) 33 p[i] = bar; 34 i = iold = 0; 35 while (i < m) { 36 if (*offptr == 15) 37 break; 38 h[i] = 0; 39 if (board[bar]) { 40 if (i == 1 || m == 4) 41 g[i] = bar+cturn*D1; 42 else 43 g[i] = bar+cturn*D0; 44 if (r = makmove(i)) { 45 if (d0 || m == 4) 46 break; 47 swap; 48 movback (i); 49 if (i > iold) 50 iold = i; 51 for (i = 0; i < 4; i++) 52 p[i] = bar; 53 i = 0; 54 } else 55 i++; 56 continue; 57 } 58 if ((p[i] += cturn) == home) { 59 if (i > iold) 60 iold = i; 61 if (m == 2 && i) { 62 movback(i); 63 p[i--] = bar; 64 if (p[i] != bar) 65 continue; 66 else 67 break; 68 } 69 if (d0 || m == 4) 70 break; 71 swap; 72 movback (i); 73 for (i = 0; i < 4; i++) 74 p[i] = bar; 75 i = 0; 76 continue; 77 } 78 if (i == 1 || m == 4) 79 g[i] = p[i]+cturn*D1; 80 else 81 g[i] = p[i]+cturn*D0; 82 if (g[i]*cturn > home) { 83 if (*offptr >= 0) 84 g[i] = home; 85 else 86 continue; 87 } 88 if (board[p[i]]*cturn > 0 && (r = makmove(i)) == 0) 89 i++; 90 } 91 movback (i); 92 return (iold > i? iold: i); 93 } 94