2 * moves.c - Move generation and checking
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
10 * Enhancements Copyright 2005 Alessandro Scotti
12 * The following terms apply to Digital Equipment Corporation's copyright
14 * ------------------------------------------------------------------------
17 * Permission to use, copy, modify, and distribute this software and its
18 * documentation for any purpose and without fee is hereby granted,
19 * provided that the above copyright notice appear in all copies and that
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
59 #else /* not HAVE_STRING_H */
61 #endif /* not HAVE_STRING_H */
67 int WhitePiece P((ChessSquare));
68 int BlackPiece P((ChessSquare));
69 int SameColor P((ChessSquare, ChessSquare));
70 int PosFlags(int index);
72 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
78 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
84 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
87 int SameColor(piece1, piece2)
88 ChessSquare piece1, piece2;
90 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
91 (int) piece1 < (int) BlackPawn &&
92 (int) piece2 >= (int) WhitePawn &&
93 (int) piece2 < (int) BlackPawn)
94 || ((int) piece1 >= (int) BlackPawn &&
95 (int) piece1 < (int) EmptySquare &&
96 (int) piece2 >= (int) BlackPawn &&
97 (int) piece2 < (int) EmptySquare);
100 char pieceToChar[] = {
101 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
102 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
103 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
104 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
106 char pieceNickName[EmptySquare];
111 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
112 return pieceToChar[(int) p];
115 int PieceToNumber(p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
119 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
121 while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
125 ChessSquare CharToPiece(c)
129 for(i=0; i< (int) EmptySquare; i++)
130 if(pieceNickName[i] == c) return (ChessSquare) i;
131 for(i=0; i< (int) EmptySquare; i++)
132 if(pieceToChar[i] == c) return (ChessSquare) i;
136 void CopyBoard(to, from)
141 for (i = 0; i < BOARD_HEIGHT; i++)
142 for (j = 0; j < BOARD_WIDTH; j++)
143 to[i][j] = from[i][j];
144 for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
145 to[CASTLING][j] = from[CASTLING][j];
146 to[HOLDINGS_SET] = 0; // flag used in ICS play
149 int CompareBoards(board1, board2)
150 Board board1, board2;
154 for (i = 0; i < BOARD_HEIGHT; i++)
155 for (j = 0; j < BOARD_WIDTH; j++) {
156 if (board1[i][j] != board2[i][j])
163 /* Call callback once for each pseudo-legal move in the given
164 position, except castling moves. A move is pseudo-legal if it is
165 legal, or if it would be legal except that it leaves the king in
166 check. In the arguments, epfile is EP_NONE if the previous move
167 was not a double pawn push, or the file 0..7 if it was, or
168 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
169 Promotion moves generated are to Queen only.
171 void GenPseudoLegal(board, flags, callback, closure)
174 MoveCallback callback;
178 int i, j, d, s, fs, rs, rt, ft, m;
179 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
180 int promoRank = gameInfo.variant == VariantMakruk ? 3 : 1;
182 for (rf = 0; rf < BOARD_HEIGHT; rf++)
183 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
186 if (flags & F_WHITE_ON_MOVE) {
187 if (!WhitePiece(board[rf][ff])) continue;
189 if (!BlackPiece(board[rf][ff])) continue;
191 m = 0; piece = board[rf][ff];
192 if(PieceToChar(piece) == '~')
193 piece = (ChessSquare) ( DEMOTED piece );
194 if(gameInfo.variant == VariantShogi)
195 piece = (ChessSquare) ( SHOGI piece );
198 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
200 /* can't happen ([HGM] except for faries...) */
204 if(gameInfo.variant == VariantXiangqi) {
205 /* [HGM] capture and move straight ahead in Xiangqi */
206 if (rf < BOARD_HEIGHT-1 &&
207 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
208 callback(board, flags, NormalMove,
209 rf, ff, rf + 1, ff, closure);
211 /* and move sideways when across the river */
212 for (s = -1; s <= 1; s += 2) {
213 if (rf >= BOARD_HEIGHT>>1 &&
214 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
215 !WhitePiece(board[rf][ff+s]) ) {
216 callback(board, flags, NormalMove,
217 rf, ff, rf, ff+s, closure);
222 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
223 callback(board, flags,
224 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
225 rf, ff, rf + 1, ff, closure);
227 if (rf == 1 && board[2][ff] == EmptySquare &&
228 gameInfo.variant != VariantShatranj && /* [HGM] */
229 gameInfo.variant != VariantCourier && /* [HGM] */
230 board[3][ff] == EmptySquare ) {
231 callback(board, flags, NormalMove,
232 rf, ff, 3, ff, closure);
234 for (s = -1; s <= 1; s += 2) {
235 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
236 ((flags & F_KRIEGSPIEL_CAPTURE) ||
237 BlackPiece(board[rf + 1][ff + s]))) {
238 callback(board, flags,
239 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
240 rf, ff, rf + 1, ff + s, closure);
242 if (rf == BOARD_HEIGHT-4) {
243 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
244 (epfile == ff + s || epfile == EP_UNKNOWN) &&
245 board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
246 board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
247 callback(board, flags, WhiteCapturesEnPassant,
248 rf, ff, 5, ff + s, closure);
255 if(gameInfo.variant == VariantXiangqi) {
256 /* [HGM] capture straight ahead in Xiangqi */
257 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
258 callback(board, flags, NormalMove,
259 rf, ff, rf - 1, ff, closure);
261 /* and move sideways when across the river */
262 for (s = -1; s <= 1; s += 2) {
263 if (rf < BOARD_HEIGHT>>1 &&
264 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
265 !BlackPiece(board[rf][ff+s]) ) {
266 callback(board, flags, NormalMove,
267 rf, ff, rf, ff+s, closure);
272 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
273 callback(board, flags,
274 rf <= promoRank ? BlackPromotion : NormalMove,
275 rf, ff, rf - 1, ff, closure);
277 if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
278 gameInfo.variant != VariantShatranj && /* [HGM] */
279 gameInfo.variant != VariantCourier && /* [HGM] */
280 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
281 callback(board, flags, NormalMove,
282 rf, ff, BOARD_HEIGHT-4, ff, closure);
284 for (s = -1; s <= 1; s += 2) {
285 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
286 ((flags & F_KRIEGSPIEL_CAPTURE) ||
287 WhitePiece(board[rf - 1][ff + s]))) {
288 callback(board, flags,
289 rf <= promoRank ? BlackPromotion : NormalMove,
290 rf, ff, rf - 1, ff + s, closure);
293 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
294 (epfile == ff + s || epfile == EP_UNKNOWN) &&
295 board[3][ff + s] == WhitePawn &&
296 board[2][ff + s] == EmptySquare) {
297 callback(board, flags, BlackCapturesEnPassant,
298 rf, ff, 2, ff + s, closure);
309 for (i = -1; i <= 1; i += 2)
310 for (j = -1; j <= 1; j += 2)
311 for (s = 1; s <= 2; s++) {
314 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
315 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
316 && !SameColor(board[rf][ff], board[rt][ft]))
317 callback(board, flags, NormalMove,
318 rf, ff, rt, ft, closure);
322 case SHOGI WhiteKnight:
323 for (s = -1; s <= 1; s += 2) {
324 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
325 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
326 callback(board, flags, NormalMove,
327 rf, ff, rf + 2, ff + s, closure);
332 case SHOGI BlackKnight:
333 for (s = -1; s <= 1; s += 2) {
334 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
335 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
336 callback(board, flags, NormalMove,
337 rf, ff, rf - 2, ff + s, closure);
344 for (d = 0; d <= 1; d++)
345 for (s = -1; s <= 1; s += 2) {
348 rt = rf + (i * s) * d;
349 ft = ff + (i * s) * (1 - d);
350 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
351 if (m == 0 && board[rt][ft] == EmptySquare)
352 callback(board, flags, NormalMove,
353 rf, ff, rt, ft, closure);
354 if (m == 1 && board[rt][ft] != EmptySquare &&
355 !SameColor(board[rf][ff], board[rt][ft]) )
356 callback(board, flags, NormalMove,
357 rf, ff, rt, ft, closure);
358 if (board[rt][ft] != EmptySquare && m++) break;
363 /* Gold General (and all its promoted versions) . First do the */
364 /* diagonal forward steps, then proceed as normal Wazir */
365 case SHOGI WhiteWazir:
366 case SHOGI (PROMOTED WhitePawn):
367 case SHOGI (PROMOTED WhiteKnight):
368 case SHOGI (PROMOTED WhiteQueen):
369 case SHOGI (PROMOTED WhiteFerz):
370 for (s = -1; s <= 1; s += 2) {
371 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
372 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
373 callback(board, flags, NormalMove,
374 rf, ff, rf + 1, ff + s, closure);
379 case SHOGI BlackWazir:
380 case SHOGI (PROMOTED BlackPawn):
381 case SHOGI (PROMOTED BlackKnight):
382 case SHOGI (PROMOTED BlackQueen):
383 case SHOGI (PROMOTED BlackFerz):
384 for (s = -1; s <= 1; s += 2) {
385 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
386 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
387 callback(board, flags, NormalMove,
388 rf, ff, rf - 1, ff + s, closure);
395 for (d = 0; d <= 1; d++)
396 for (s = -1; s <= 1; s += 2) {
398 ft = ff + s * (1 - d);
399 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
400 && !SameColor(board[rf][ff], board[rt][ft]) &&
401 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
402 callback(board, flags, NormalMove,
403 rf, ff, rt, ft, closure);
409 /* [HGM] support Shatranj pieces */
410 for (rs = -1; rs <= 1; rs += 2)
411 for (fs = -1; fs <= 1; fs += 2) {
414 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
415 && ( gameInfo.variant != VariantXiangqi ||
416 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
418 && !SameColor(board[rf][ff], board[rt][ft]))
419 callback(board, flags, NormalMove,
420 rf, ff, rt, ft, closure);
424 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
425 case SHOGI WhiteCardinal:
426 case SHOGI BlackCardinal:
429 /* Capablanca Archbishop continues as Knight */
434 /* Shogi Bishops are ordinary Bishops */
435 case SHOGI WhiteBishop:
436 case SHOGI BlackBishop:
439 for (rs = -1; rs <= 1; rs += 2)
440 for (fs = -1; fs <= 1; fs += 2)
444 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
445 if (SameColor(board[rf][ff], board[rt][ft])) break;
446 callback(board, flags, NormalMove,
447 rf, ff, rt, ft, closure);
448 if (board[rt][ft] != EmptySquare) break;
450 if(m==1) goto mounted;
451 if(m==2) goto finishGold;
452 /* Bishop falls through */
455 /* Shogi Lance is unlike anything, and asymmetric at that */
456 case SHOGI WhiteQueen:
460 if (rt >= BOARD_HEIGHT) break;
461 if (SameColor(board[rf][ff], board[rt][ft])) break;
462 callback(board, flags, NormalMove,
463 rf, ff, rt, ft, closure);
464 if (board[rt][ft] != EmptySquare) break;
468 case SHOGI BlackQueen:
473 if (SameColor(board[rf][ff], board[rt][ft])) break;
474 callback(board, flags, NormalMove,
475 rf, ff, rt, ft, closure);
476 if (board[rt][ft] != EmptySquare) break;
480 /* Shogi Dragon King has to continue as Ferz after Rook moves */
481 case SHOGI WhiteDragon:
482 case SHOGI BlackDragon:
485 /* Capablanca Chancellor sets flag to continue as Knight */
490 /* Shogi Rooks are ordinary Rooks */
491 case SHOGI WhiteRook:
492 case SHOGI BlackRook:
495 for (d = 0; d <= 1; d++)
496 for (s = -1; s <= 1; s += 2)
498 rt = rf + (i * s) * d;
499 ft = ff + (i * s) * (1 - d);
500 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
501 if (SameColor(board[rf][ff], board[rt][ft])) break;
502 callback(board, flags, NormalMove,
503 rf, ff, rt, ft, closure);
504 if (board[rt][ft] != EmptySquare) break;
506 if(m==1) goto mounted;
507 if(m==2) goto finishSilver;
512 for (rs = -1; rs <= 1; rs++)
513 for (fs = -1; fs <= 1; fs++) {
514 if (rs == 0 && fs == 0) continue;
518 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
519 if (SameColor(board[rf][ff], board[rt][ft])) break;
520 callback(board, flags, NormalMove,
521 rf, ff, rt, ft, closure);
522 if (board[rt][ft] != EmptySquare) break;
527 /* Shogi Pawn and Silver General: first the Pawn move, */
528 /* then the General continues like a Ferz */
530 if(gameInfo.variant != VariantMakruk) goto commoner;
531 case SHOGI WhitePawn:
532 case SHOGI WhiteFerz:
533 if (rf < BOARD_HEIGHT-1 &&
534 !SameColor(board[rf][ff], board[rf + 1][ff]) )
535 callback(board, flags, NormalMove,
536 rf, ff, rf + 1, ff, closure);
537 if(piece != SHOGI WhitePawn) goto finishSilver;
541 if(gameInfo.variant != VariantMakruk) goto commoner;
542 case SHOGI BlackPawn:
543 case SHOGI BlackFerz:
545 !SameColor(board[rf][ff], board[rf - 1][ff]) )
546 callback(board, flags, NormalMove,
547 rf, ff, rf - 1, ff, closure);
548 if(piece == SHOGI BlackPawn) break;
553 /* [HGM] support Shatranj pieces */
554 for (rs = -1; rs <= 1; rs += 2)
555 for (fs = -1; fs <= 1; fs += 2) {
558 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
559 if (!SameColor(board[rf][ff], board[rt][ft]) &&
560 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
561 callback(board, flags, NormalMove,
562 rf, ff, rt, ft, closure);
568 m++; // [HGM] superchess: use for Centaur
570 case SHOGI WhiteKing:
571 case SHOGI BlackKing:
575 for (i = -1; i <= 1; i++)
576 for (j = -1; j <= 1; j++) {
577 if (i == 0 && j == 0) continue;
580 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
581 if (SameColor(board[rf][ff], board[rt][ft])) continue;
582 callback(board, flags, NormalMove,
583 rf, ff, rt, ft, closure);
585 if(m==1) goto mounted;
588 case WhiteNightrider:
589 case BlackNightrider:
590 for (i = -1; i <= 1; i += 2)
591 for (j = -1; j <= 1; j += 2)
592 for (s = 1; s <= 2; s++) { int k;
596 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
597 if (SameColor(board[rf][ff], board[rt][ft])) break;
598 callback(board, flags, NormalMove,
599 rf, ff, rt, ft, closure);
600 if (board[rt][ft] != EmptySquare) break;
604 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
610 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
623 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
624 int rf, int ff, int rt, int ft,
627 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
634 register GenLegalClosure *cl = (GenLegalClosure *) closure;
636 if (!(flags & F_IGNORE_CHECK) &&
637 CheckTest(board, flags, rf, ff, rt, ft,
638 kind == WhiteCapturesEnPassant ||
639 kind == BlackCapturesEnPassant)) return;
640 if (flags & F_ATOMIC_CAPTURE) {
641 if (board[rt][ft] != EmptySquare ||
642 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
644 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
645 if (board[rf][ff] == king) return;
646 for (r = rt-1; r <= rt+1; r++) {
647 for (f = ft-1; f <= ft+1; f++) {
648 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
649 board[r][f] == king) return;
654 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
661 int captures; // [HGM] losers
662 } LegalityTestClosure;
665 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
666 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
667 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
668 moves that would destroy your own king. The CASTLE_OK flags are
669 true if castling is not yet ruled out by a move of the king or
670 rook. Return TRUE if the player on move is currently in check and
671 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
672 int GenLegal(board, flags, callback, closure)
675 MoveCallback callback;
679 int ff, ft, k, left, right;
680 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
681 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
685 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl);
688 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
690 /* Generate castling moves */
691 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
692 wKing = WhiteUnicorn; bKing = BlackUnicorn;
695 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
696 if ((flags & F_WHITE_ON_MOVE) &&
697 (flags & F_WHITE_KCASTLE_OK) &&
698 board[0][ff] == wKing &&
699 board[0][ff + 1] == EmptySquare &&
700 board[0][ff + 2] == EmptySquare &&
701 board[0][BOARD_RGHT-3] == EmptySquare &&
702 board[0][BOARD_RGHT-2] == EmptySquare &&
703 board[0][BOARD_RGHT-1] == WhiteRook &&
704 castlingRights[0] != NoRights && /* [HGM] check rights */
705 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
707 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
708 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
709 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
710 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
712 callback(board, flags,
713 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
714 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
716 if ((flags & F_WHITE_ON_MOVE) &&
717 (flags & F_WHITE_QCASTLE_OK) &&
718 board[0][ff] == wKing &&
719 board[0][ff - 1] == EmptySquare &&
720 board[0][ff - 2] == EmptySquare &&
721 board[0][BOARD_LEFT+2] == EmptySquare &&
722 board[0][BOARD_LEFT+1] == EmptySquare &&
723 board[0][BOARD_LEFT+0] == WhiteRook &&
724 castlingRights[1] != NoRights && /* [HGM] check rights */
725 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
727 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
728 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
729 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
731 callback(board, flags,
732 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
733 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
735 if (!(flags & F_WHITE_ON_MOVE) &&
736 (flags & F_BLACK_KCASTLE_OK) &&
737 board[BOARD_HEIGHT-1][ff] == bKing &&
738 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
739 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
740 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
741 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
742 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
743 castlingRights[3] != NoRights && /* [HGM] check rights */
744 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
746 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
747 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
748 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
749 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
751 callback(board, flags,
752 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
753 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
755 if (!(flags & F_WHITE_ON_MOVE) &&
756 (flags & F_BLACK_QCASTLE_OK) &&
757 board[BOARD_HEIGHT-1][ff] == bKing &&
758 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
759 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
760 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
761 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
762 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
763 castlingRights[4] != NoRights && /* [HGM] check rights */
764 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
766 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
767 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
768 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
770 callback(board, flags,
771 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
772 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
776 if(flags & F_FRC_TYPE_CASTLING) {
778 /* generate all potential FRC castling moves (KxR), ignoring flags */
779 /* [HGM] test if the Rooks we find have castling rights */
782 if ((flags & F_WHITE_ON_MOVE) != 0) {
783 ff = castlingRights[2]; /* King file if we have any rights */
784 if(ff != NoRights && board[0][ff] == WhiteKing) {
785 if (appData.debugMode) {
786 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
787 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
789 ft = castlingRights[0]; /* Rook file if we have H-side rights */
791 right = BOARD_RGHT-2;
792 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
793 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
794 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
795 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
796 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
797 if(ft != NoRights && board[0][ft] == WhiteRook)
798 callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
800 ft = castlingRights[1]; /* Rook file if we have A-side rights */
803 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
804 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
805 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
806 if(ff > BOARD_LEFT+2)
807 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
808 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
809 if(ft != NoRights && board[0][ft] == WhiteRook)
810 callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
813 ff = castlingRights[5]; /* King file if we have any rights */
814 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
815 ft = castlingRights[3]; /* Rook file if we have H-side rights */
817 right = BOARD_RGHT-2;
818 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
819 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
820 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
821 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
822 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
823 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
824 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
826 ft = castlingRights[4]; /* Rook file if we have A-side rights */
829 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
830 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
831 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
832 if(ff > BOARD_LEFT+2)
833 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
834 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
835 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
836 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
852 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
853 int rf, int ff, int rt, int ft,
857 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
864 register CheckTestClosure *cl = (CheckTestClosure *) closure;
866 if (rt == cl->rking && ft == cl->fking) cl->check++;
870 /* If the player on move were to move from (rf, ff) to (rt, ft), would
871 he leave himself in check? Or if rf == -1, is the player on move
872 in check now? enPassant must be TRUE if the indicated move is an
873 e.p. capture. The possibility of castling out of a check along the
874 back rank is not accounted for (i.e., we still return nonzero), as
875 this is illegal anyway. Return value is the number of times the
877 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
880 int rf, ff, rt, ft, enPassant;
883 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
884 ChessSquare captured = EmptySquare;
885 /* Suppress warnings on uninitialized variables */
887 if(gameInfo.variant == VariantXiangqi)
888 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
889 if(gameInfo.variant == VariantKnightmate)
890 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
894 captured = board[rf][ft];
895 board[rf][ft] = EmptySquare;
897 captured = board[rt][ft];
899 board[rt][ft] = board[rf][ff];
900 board[rf][ff] = EmptySquare;
901 } else board[rt][ft] = ff; // [HGM] drop
903 /* For compatibility with ICS wild 9, we scan the board in the
904 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
905 and we test only whether that one is in check. */
907 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
908 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
909 if (board[cl.rking][cl.fking] == king) {
910 if(gameInfo.variant == VariantXiangqi) {
911 /* [HGM] In Xiangqi opposing Kings means check as well */
913 dir = (king >= BlackPawn) ? -1 : 1;
914 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
915 board[i][cl.fking] == EmptySquare; i+=dir );
916 if(i>=0 && i<BOARD_HEIGHT &&
917 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
921 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl);
922 goto undo_move; /* 2-level break */
929 board[rf][ff] = board[rt][ft];
931 board[rf][ft] = captured;
932 board[rt][ft] = EmptySquare;
934 board[rt][ft] = captured;
936 } else board[rt][ft] = EmptySquare; // [HGM] drop
938 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
941 ChessMove LegalDrop(board, flags, piece, rt, ft)
946 { // [HGM] put drop legality testing in separate routine for clarity
948 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
949 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
950 n = PieceToNumber(piece);
951 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
952 return ImpossibleMove; // piece not available
953 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
954 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
955 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
956 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
957 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
958 if(piece == WhitePawn || piece == BlackPawn) {
960 for(r=1; r<BOARD_HEIGHT-1; r++)
961 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
962 // should still test if we mate with this Pawn
965 if( (piece == WhitePawn || piece == BlackPawn) &&
966 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
967 return IllegalMove; /* no pawn drops on 1st/8th */
969 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
970 if (!(flags & F_IGNORE_CHECK) &&
971 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
972 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
975 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
976 int rf, int ff, int rt, int ft,
979 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
986 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
988 // if (appData.debugMode) {
989 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
991 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
992 cl->captures++; // [HGM] losers: count legal captures
993 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
997 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1000 int rf, ff, rt, ft, promoChar;
1002 LegalityTestClosure cl; ChessSquare piece, *castlingRights = board[CASTLING];
1004 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1005 piece = board[rf][ff];
1007 if (appData.debugMode) {
1009 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1010 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1012 /* [HGM] Lance, Cobra and Falcon are wildcard pieces; consider all their moves legal */
1013 /* (perhaps we should disallow moves that obviously leave us in check?) */
1014 if(piece == WhiteFalcon || piece == BlackFalcon ||
1015 piece == WhiteCobra || piece == BlackCobra ||
1016 piece == WhiteLance || piece == BlackLance)
1017 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1023 cl.kind = IllegalMove;
1024 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1025 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl);
1026 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1027 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1028 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1030 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1031 if(gameInfo.variant == VariantShogi) {
1032 /* [HGM] Shogi promotions. '=' means defer */
1033 if(rf != DROP_RANK && cl.kind == NormalMove) {
1034 ChessSquare piece = board[rf][ff];
1036 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1037 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=' &&
1038 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(promoChar) )
1039 cl.kind = IllegalMove;
1040 else if(flags & F_WHITE_ON_MOVE) {
1041 if( (int) piece < (int) WhiteWazir &&
1042 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1043 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1044 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1045 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1046 else /* promotion optional, default is promote */
1047 cl.kind = promoChar == '=' ? WhiteNonPromotion : WhitePromotion;
1049 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1050 NormalMove : IllegalMove;
1052 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1053 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1054 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1055 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1056 else /* promotion optional, default is promote */
1057 cl.kind = promoChar == '=' ? BlackNonPromotion : BlackPromotion;
1059 } else cl.kind = (promoChar == NULLCHAR || promoChar == '=') ? NormalMove : IllegalMove;
1063 if (promoChar != NULLCHAR) {
1064 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1065 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1066 if(CharToPiece(promoChar) == EmptySquare) cl.kind = ImpossibleMove; // non-existing piece
1068 cl.kind = IllegalMove;
1078 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1079 int rf, int ff, int rt, int ft,
1082 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1089 register MateTestClosure *cl = (MateTestClosure *) closure;
1094 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1095 int MateTest(board, flags)
1100 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1101 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1103 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1104 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1105 nrKing += (board[r][f] == king); // stm has king
1106 if( board[r][f] != EmptySquare ) {
1107 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1112 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1113 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1114 case VariantShatranj:
1115 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1119 if(nrKing == 0) return MT_NOKING;
1122 if(myPieces == 1) return MT_BARE;
1125 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl);
1126 // [HGM] 3check: yet to do!
1128 return inCheck ? MT_CHECK : MT_NONE;
1130 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper || gameInfo.variant != VariantGreat) { // drop game
1131 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1132 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1133 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1134 if(board[n][holdings] != EmptySquare) {
1135 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1136 if(moveType == WhiteDrop || moveType == BlackDrop) return MT_CHECK; // we can resolve check by legal drop
1139 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1140 return myPieces == hisPieces ? MT_STALEMATE :
1141 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1142 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1143 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1145 return inCheck ? MT_CHECKMATE
1146 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1147 MT_STAINMATE : MT_STALEMATE;
1152 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1153 int rf, int ff, int rt, int ft,
1156 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1163 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1164 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1166 // [HGM] wild: for wild-card pieces rt and rf are dummies
1167 if(piece == WhiteFalcon || piece == BlackFalcon ||
1168 piece == WhiteCobra || piece == BlackCobra ||
1169 piece == WhiteLance || piece == BlackLance)
1172 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1173 || PieceToChar(board[rf][ff]) == '~'
1174 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1176 (cl->rfIn == -1 || cl->rfIn == rf) &&
1177 (cl->ffIn == -1 || cl->ffIn == ff) &&
1178 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1179 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1182 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1183 // [HGM] oneclick: if multiple moves, be sure we remember capture
1184 cl->piece = board[rf][ff];
1187 cl->rt = wildCard ? cl->rtIn : rt;
1188 cl->ft = wildCard ? cl->ftIn : ft;
1191 cl->captures += (board[cl->rt][cl->ft] != EmptySquare); // [HGM] oneclick: count captures
1195 void Disambiguate(board, flags, closure)
1198 DisambiguateClosure *closure;
1200 int illegal = 0; char c = closure->promoCharIn;
1202 closure->count = closure->captures = 0;
1203 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1204 closure->kind = ImpossibleMove;
1205 if (appData.debugMode) {
1206 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1207 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1208 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1210 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure);
1211 if (closure->count == 0) {
1212 /* See if it's an illegal move due to check */
1214 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure);
1215 if (closure->count == 0) {
1216 /* No, it's not even that */
1217 if (appData.debugMode) { int i, j;
1218 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1219 for(j=0; j<BOARD_WIDTH; j++)
1220 fprintf(debugFP, "%3d", (int) board[i][j]);
1221 fprintf(debugFP, "\n");
1228 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1229 if(gameInfo.variant == VariantShogi) {
1230 /* [HGM] Shogi promotions. On input, '=' means defer, NULL promote. Afterwards, c is set to '+' for promotions, NULL other */
1231 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1232 ChessSquare piece = closure->piece;
1233 if(c != NULLCHAR && c != '+' && c != '=' &&
1234 ToUpper(PieceToChar(PROMOTED piece)) != ToUpper(c) )
1235 closure->kind = IllegalMove; // the only allowed cases are '+', '=' and the promoted partner.
1236 else if(flags & F_WHITE_ON_MOVE) {
1237 if( (int) piece < (int) WhiteWazir &&
1238 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1239 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1240 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1241 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1242 else /* promotion optional, default is promote */
1243 closure->kind = c == '=' ? WhiteNonPromotion : WhitePromotion;
1244 } else closure->kind = (c == NULLCHAR || c == '=') ? NormalMove : IllegalMove;
1246 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1247 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1248 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1249 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1250 else /* promotion optional, default is promote */
1251 closure->kind = c == '=' ? BlackNonPromotion : BlackPromotion;
1252 } else closure->kind = (c == NULLCHAR || c == '=') ? NormalMove : IllegalMove;
1255 c = (closure->kind == WhitePromotion || closure->kind == BlackPromotion) ? '+' : NULLCHAR;
1257 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1258 if(c == NULLCHAR) c = 'q'; // even in Shatranj, Courier, Makruk, as Apply move corrects this to Ferz (how messy!)
1259 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1261 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1262 if(c != '+' && c != NULLCHAR && CharToPiece(c) == EmptySquare) closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1263 if (closure->count > 1) {
1264 closure->kind = AmbiguousMove;
1267 /* Note: If more than one illegal move matches, but no legal
1268 moves, we return IllegalMove, not AmbiguousMove. Caller
1269 can look at closure->count to detect this.
1271 closure->kind = IllegalMove;
1273 if (appData.debugMode) {
1274 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1275 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1276 closure->promoChar >= ' ' ? closure->promoChar:'-');
1290 } CoordsToAlgebraicClosure;
1292 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1293 ChessMove kind, int rf, int ff,
1294 int rt, int ft, VOIDSTAR closure));
1296 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1303 register CoordsToAlgebraicClosure *cl =
1304 (CoordsToAlgebraicClosure *) closure;
1306 if (rt == cl->rt && ft == cl->ft &&
1307 (board[rf][ff] == cl->piece
1308 || PieceToChar(board[rf][ff]) == '~' &&
1309 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1313 cl->kind = kind; /* this is the move we want */
1315 cl->file++; /* need file to rule out this move */
1319 cl->rank++; /* need rank to rule out this move */
1321 cl->either++; /* rank or file will rule out this move */
1327 /* Convert coordinates to normal algebraic notation.
1328 promoChar must be NULLCHAR or 'x' if not a promotion.
1330 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1339 char *outp = out, c;
1340 CoordsToAlgebraicClosure cl;
1342 if (rf == DROP_RANK) {
1343 /* Bughouse piece drop */
1344 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1349 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1351 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1354 if (promoChar == 'x') promoChar = NULLCHAR;
1355 piece = board[rf][ff];
1356 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1358 if (appData.debugMode)
1359 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1363 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1364 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1365 /* Keep short notation if move is illegal only because it
1366 leaves the player in check, but still return IllegalMove */
1367 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1368 if (kind == IllegalMove) break;
1373 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1374 /* Non-capture; use style "e5" */
1377 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1379 /* Capture; use style "exd5" */
1380 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1381 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1385 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1387 /* Use promotion suffix style "=Q" */
1389 if (appData.debugMode)
1390 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1391 if (promoChar != NULLCHAR) {
1392 if(gameInfo.variant == VariantShogi) {
1393 /* [HGM] ... but not in Shogi! */
1394 *outp++ = promoChar == '=' ? '=' : '+';
1397 *outp++ = ToUpper(promoChar);
1406 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1407 /* Code added by Tord: FRC castling. */
1408 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1409 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1411 safeStrCpy(out, "O-O", MOVE_LEN);
1413 safeStrCpy(out, "O-O-O", MOVE_LEN);
1414 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1416 /* End of code added by Tord */
1417 /* Test for castling or ICS wild castling */
1418 /* Use style "O-O" (oh-oh) for PGN compatibility */
1419 else if (rf == rt &&
1420 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1421 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1422 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1423 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1424 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1425 safeStrCpy(out, "O-O", MOVE_LEN);
1427 safeStrCpy(out, "O-O-O", MOVE_LEN);
1429 /* This notation is always unambiguous, unless there are
1430 kings on both the d and e files, with "wild castling"
1431 possible for the king on the d file and normal castling
1432 possible for the other. ICS rules for wild 9
1433 effectively make castling illegal for either king in
1434 this situation. So I am not going to worry about it;
1435 I'll just generate an ambiguous O-O in this case.
1437 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1440 /* else fall through */
1448 cl.kind = IllegalMove;
1449 cl.rank = cl.file = cl.either = 0;
1450 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1452 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1453 /* Generate pretty moves for moving into check, but
1454 still return IllegalMove.
1456 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1457 if (cl.kind == IllegalMove) break;
1458 cl.kind = IllegalMove;
1461 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1462 else "Ngf3" or "Ngxf7",
1463 else "N1f3" or "N5xf7",
1464 else "Ng1f3" or "Ng5xf7".
1466 c = PieceToChar(piece) ;
1467 if( c == '~' || c == '+') {
1468 /* [HGM] print nonexistent piece as its demoted version */
1469 piece = (ChessSquare) (DEMOTED piece);
1471 if(c=='+') *outp++ = c;
1472 *outp++ = ToUpper(PieceToChar(piece));
1474 if (cl.file || (cl.either && !cl.rank)) {
1480 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1483 if(board[rt][ft] != EmptySquare)
1489 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1491 if (gameInfo.variant == VariantShogi) {
1492 /* [HGM] in Shogi non-pawns can promote */
1493 if(flags & F_WHITE_ON_MOVE) {
1494 if( (int) cl.piece < (int) WhiteWazir &&
1495 (rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1496 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1497 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1498 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1499 else cl.kind = WhitePromotion; /* promotion optional */
1500 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1501 NormalMove : IllegalMove;
1503 if( (int) cl.piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1504 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1505 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1506 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1507 else cl.kind = BlackPromotion; /* promotion optional */
1508 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
1509 NormalMove : IllegalMove;
1511 if(cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1512 /* for optional promotions append '+' or '=' */
1513 if(promoChar == '=') {
1515 cl.kind = NormalMove;
1516 } else *outp++ = '+';
1518 } else if(cl.kind == IllegalMove) {
1519 /* Illegal move specifies any given promotion */
1520 if(promoChar != NULLCHAR && promoChar != 'x') {
1522 *outp++ = ToUpper(promoChar);
1529 /* [HGM] Always long notation for fairies we don't know */
1534 case WhiteGrasshopper:
1535 case BlackGrasshopper:
1537 /* Moving a nonexistent piece */
1541 /* Not a legal move, even ignoring check.
1542 If there was a piece on the from square,
1543 use style "Ng1g3" or "Ng1xe8";
1544 if there was a pawn or nothing (!),
1545 use style "g1g3" or "g1xe8". Use "x"
1546 if a piece was on the to square, even
1547 a piece of the same color.
1550 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1551 *outp++ = ToUpper(PieceToChar(piece));
1556 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1557 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1561 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1562 /* Use promotion suffix style "=Q" */
1563 if (promoChar != NULLCHAR && promoChar != 'x') {
1565 *outp++ = ToUpper(promoChar);
1572 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1581 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1583 int preyStackPointer, chaseStackPointer;
1586 char rf, ff, rt, ft;
1596 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1598 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1599 int rf, int ff, int rt, int ft,
1602 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1608 { // For adding captures that can lead to chase indictment to the chaseStack
1609 if(board[rt][ft] == EmptySquare) return; // non-capture
1610 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1611 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1612 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1613 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1614 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1615 chaseStack[chaseStackPointer].rf = rf;
1616 chaseStack[chaseStackPointer].ff = ff;
1617 chaseStack[chaseStackPointer].rt = rt;
1618 chaseStack[chaseStackPointer].ft = ft;
1619 chaseStackPointer++;
1622 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1623 int rf, int ff, int rt, int ft,
1626 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1632 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1634 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1636 if(board[rt][ft] == EmptySquare) return; // no capture
1637 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1638 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1640 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1641 for(i=0; i<chaseStackPointer; i++) {
1642 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1643 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1644 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1645 chaseStack[i] = chaseStack[--chaseStackPointer];
1651 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1652 int rf, int ff, int rt, int ft,
1655 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1661 { // for determining if a piece (given through the closure) is protected
1662 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1664 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1665 if(appData.debugMode && board[rt][ft] != EmptySquare)
1666 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1669 extern char moveList[MAX_MOVES][MOVE_LEN];
1671 int PerpetualChase(int first, int last)
1672 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1675 ChessSquare captured;
1677 preyStackPointer = 0; // clear stack of chased pieces
1678 for(i=first; i<last; i+=2) { // for all positions with same side to move
1679 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1680 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1681 // determine all captures possible after the move, and put them on chaseStack
1682 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl);
1683 if(appData.debugMode) { int n;
1684 for(n=0; n<chaseStackPointer; n++)
1685 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1686 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1687 fprintf(debugFP, ": all capts\n");
1689 // determine all captures possible before the move, and delete them from chaseStack
1690 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1691 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1692 cl.rt = moveList[i][3]-ONE;
1693 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1694 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl);
1695 if(appData.debugMode) { int n;
1696 for(n=0; n<chaseStackPointer; n++)
1697 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1698 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1699 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1701 // chaseSack now contains all captures made possible by the move
1702 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1703 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1704 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1706 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1707 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1709 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1710 continue; // C or H attack on R is always chase; leave on chaseStack
1712 if(attacker == victim) {
1713 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1714 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1715 // we can capture back with equal piece, so this is no chase but a sacrifice
1716 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1717 j--; /* ! */ continue;
1722 // the attack is on a lower piece, or on a pinned or blocked equal one
1723 // test if the victim is protected by a true protector. First make the capture.
1724 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1725 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1726 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1727 // Then test if the opponent can recapture
1728 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1729 cl.rt = chaseStack[j].rt;
1730 cl.ft = chaseStack[j].ft;
1731 if(appData.debugMode) {
1732 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1734 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl); // try all moves
1735 // unmake the capture
1736 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1737 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1738 // if a recapture was found, piece is protected, and we are not chasing it.
1739 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1740 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1744 // chaseStack now contains all moves that chased
1745 if(appData.debugMode) { int n;
1746 for(n=0; n<chaseStackPointer; n++)
1747 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1748 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1749 fprintf(debugFP, ": chases\n");
1751 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1752 for(j=0; j<chaseStackPointer; j++) {
1753 preyStack[j].rank = chaseStack[j].rt;
1754 preyStack[j].file = chaseStack[j].ft;
1756 preyStackPointer = chaseStackPointer;
1759 for(j=0; j<chaseStackPointer; j++) {
1760 for(k=0; k<preyStackPointer; k++) {
1761 // search the victim of each chase move on the preyStack (first occurrence)
1762 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1763 if(k < tail) break; // piece was already identified as still being chased
1764 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1765 preyStack[tail] = preyStack[k]; // by swapping
1766 preyStack[k] = preyStack[preyStackPointer];
1772 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1773 if(appData.debugMode) { int n;
1774 for(n=0; n<preyStackPointer; n++)
1775 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1776 fprintf(debugFP, "always chased upto ply %d\n", i);
1778 // now adjust the location of the chased pieces according to opponent move
1779 for(j=0; j<preyStackPointer; j++) {
1780 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1781 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1782 preyStack[j].rank = moveList[i+1][3]-ONE;
1783 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1788 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased