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, 2011 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 if(c == '.') return EmptySquare;
130 for(i=0; i< (int) EmptySquare; i++)
131 if(pieceNickName[i] == c) return (ChessSquare) i;
132 for(i=0; i< (int) EmptySquare; i++)
133 if(pieceToChar[i] == c) return (ChessSquare) i;
137 void CopyBoard(to, from)
142 for (i = 0; i < BOARD_HEIGHT; i++)
143 for (j = 0; j < BOARD_WIDTH; j++)
144 to[i][j] = from[i][j];
145 for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
146 to[CASTLING][j] = from[CASTLING][j];
147 to[HOLDINGS_SET] = 0; // flag used in ICS play
150 int CompareBoards(board1, board2)
151 Board board1, board2;
155 for (i = 0; i < BOARD_HEIGHT; i++)
156 for (j = 0; j < BOARD_WIDTH; j++) {
157 if (board1[i][j] != board2[i][j])
164 /* Call callback once for each pseudo-legal move in the given
165 position, except castling moves. A move is pseudo-legal if it is
166 legal, or if it would be legal except that it leaves the king in
167 check. In the arguments, epfile is EP_NONE if the previous move
168 was not a double pawn push, or the file 0..7 if it was, or
169 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
170 Promotion moves generated are to Queen only.
172 void GenPseudoLegal(board, flags, callback, closure, filter)
175 MoveCallback callback;
177 ChessSquare filter; // [HGM] speed: only do moves with this piece type
180 int i, j, d, s, fs, rs, rt, ft, m;
181 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
182 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand ? 3 : 1;
184 for (rf = 0; rf < BOARD_HEIGHT; rf++)
185 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
187 int rookRange = 1000;
189 if (flags & F_WHITE_ON_MOVE) {
190 if (!WhitePiece(board[rf][ff])) continue;
192 if (!BlackPiece(board[rf][ff])) continue;
194 m = 0; piece = board[rf][ff];
195 if(PieceToChar(piece) == '~')
196 piece = (ChessSquare) ( DEMOTED piece );
197 if(filter != EmptySquare && piece != filter) continue;
198 if(gameInfo.variant == VariantShogi)
199 piece = (ChessSquare) ( SHOGI piece );
201 switch ((int)piece) {
202 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
204 /* can't happen ([HGM] except for faries...) */
208 if(gameInfo.variant == VariantXiangqi) {
209 /* [HGM] capture and move straight ahead in Xiangqi */
210 if (rf < BOARD_HEIGHT-1 &&
211 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
212 callback(board, flags, NormalMove,
213 rf, ff, rf + 1, ff, closure);
215 /* and move sideways when across the river */
216 for (s = -1; s <= 1; s += 2) {
217 if (rf >= BOARD_HEIGHT>>1 &&
218 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
219 !WhitePiece(board[rf][ff+s]) ) {
220 callback(board, flags, NormalMove,
221 rf, ff, rf, ff+s, closure);
226 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
227 callback(board, flags,
228 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
229 rf, ff, rf + 1, ff, closure);
231 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
232 gameInfo.variant != VariantShatranj && /* [HGM] */
233 gameInfo.variant != VariantCourier && /* [HGM] */
234 board[rf+2][ff] == EmptySquare ) {
235 callback(board, flags, NormalMove,
236 rf, ff, rf+2, ff, closure);
238 for (s = -1; s <= 1; s += 2) {
239 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
240 ((flags & F_KRIEGSPIEL_CAPTURE) ||
241 BlackPiece(board[rf + 1][ff + s]))) {
242 callback(board, flags,
243 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
244 rf, ff, rf + 1, ff + s, closure);
246 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
247 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
248 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
249 board[rf][ff + s] == BlackPawn &&
250 board[rf+1][ff + s] == EmptySquare) {
251 callback(board, flags, WhiteCapturesEnPassant,
252 rf, ff, rf+1, ff + s, closure);
259 if(gameInfo.variant == VariantXiangqi) {
260 /* [HGM] capture straight ahead in Xiangqi */
261 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
262 callback(board, flags, NormalMove,
263 rf, ff, rf - 1, ff, closure);
265 /* and move sideways when across the river */
266 for (s = -1; s <= 1; s += 2) {
267 if (rf < BOARD_HEIGHT>>1 &&
268 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
269 !BlackPiece(board[rf][ff+s]) ) {
270 callback(board, flags, NormalMove,
271 rf, ff, rf, ff+s, closure);
276 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
277 callback(board, flags,
278 rf <= promoRank ? BlackPromotion : NormalMove,
279 rf, ff, rf - 1, ff, closure);
281 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
282 gameInfo.variant != VariantShatranj && /* [HGM] */
283 gameInfo.variant != VariantCourier && /* [HGM] */
284 board[rf-2][ff] == EmptySquare) {
285 callback(board, flags, NormalMove,
286 rf, ff, rf-2, ff, closure);
288 for (s = -1; s <= 1; s += 2) {
289 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
290 ((flags & F_KRIEGSPIEL_CAPTURE) ||
291 WhitePiece(board[rf - 1][ff + s]))) {
292 callback(board, flags,
293 rf <= promoRank ? BlackPromotion : NormalMove,
294 rf, ff, rf - 1, ff + s, closure);
296 if (rf < BOARD_HEIGHT>>1) {
297 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
298 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
299 board[rf][ff + s] == WhitePawn &&
300 board[rf-1][ff + s] == EmptySquare) {
301 callback(board, flags, BlackCapturesEnPassant,
302 rf, ff, rf-1, ff + s, closure);
313 for (i = -1; i <= 1; i += 2)
314 for (j = -1; j <= 1; j += 2)
315 for (s = 1; s <= 2; s++) {
318 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
319 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
320 && !SameColor(board[rf][ff], board[rt][ft]))
321 callback(board, flags, NormalMove,
322 rf, ff, rt, ft, closure);
326 case SHOGI WhiteKnight:
327 for (s = -1; s <= 1; s += 2) {
328 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
329 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
330 callback(board, flags, NormalMove,
331 rf, ff, rf + 2, ff + s, closure);
336 case SHOGI BlackKnight:
337 for (s = -1; s <= 1; s += 2) {
338 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
339 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
340 callback(board, flags, NormalMove,
341 rf, ff, rf - 2, ff + s, closure);
348 for (d = 0; d <= 1; d++)
349 for (s = -1; s <= 1; s += 2) {
352 rt = rf + (i * s) * d;
353 ft = ff + (i * s) * (1 - d);
354 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
355 if (m == 0 && board[rt][ft] == EmptySquare)
356 callback(board, flags, NormalMove,
357 rf, ff, rt, ft, closure);
358 if (m == 1 && board[rt][ft] != EmptySquare &&
359 !SameColor(board[rf][ff], board[rt][ft]) )
360 callback(board, flags, NormalMove,
361 rf, ff, rt, ft, closure);
362 if (board[rt][ft] != EmptySquare && m++) break;
367 /* Gold General (and all its promoted versions) . First do the */
368 /* diagonal forward steps, then proceed as normal Wazir */
369 case SHOGI WhiteWazir:
370 case SHOGI (PROMOTED WhitePawn):
371 case SHOGI (PROMOTED WhiteKnight):
372 case SHOGI (PROMOTED WhiteQueen):
373 case SHOGI (PROMOTED WhiteFerz):
374 for (s = -1; s <= 1; s += 2) {
375 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
376 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
377 callback(board, flags, NormalMove,
378 rf, ff, rf + 1, ff + s, closure);
383 case SHOGI BlackWazir:
384 case SHOGI (PROMOTED BlackPawn):
385 case SHOGI (PROMOTED BlackKnight):
386 case SHOGI (PROMOTED BlackQueen):
387 case SHOGI (PROMOTED BlackFerz):
388 for (s = -1; s <= 1; s += 2) {
389 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
390 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
391 callback(board, flags, NormalMove,
392 rf, ff, rf - 1, ff + s, closure);
399 for (d = 0; d <= 1; d++)
400 for (s = -1; s <= 1; s += 2) {
402 ft = ff + s * (1 - d);
403 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
404 && !SameColor(board[rf][ff], board[rt][ft]) &&
405 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
406 callback(board, flags, NormalMove,
407 rf, ff, rt, ft, closure);
413 /* [HGM] support Shatranj pieces */
414 for (rs = -1; rs <= 1; rs += 2)
415 for (fs = -1; fs <= 1; fs += 2) {
418 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
419 && ( gameInfo.variant != VariantXiangqi ||
420 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
422 && !SameColor(board[rf][ff], board[rt][ft]))
423 callback(board, flags, NormalMove,
424 rf, ff, rt, ft, closure);
425 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier
426 || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
427 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
429 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
430 && !SameColor(board[rf][ff], board[rt][ft]))
431 callback(board, flags, NormalMove,
432 rf, ff, rt, ft, closure);
434 if(gameInfo.variant == VariantSpartan)
435 for(fs = -1; fs <= 1; fs += 2) {
437 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
438 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
442 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
445 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
446 for (s = -2; s <= 2; s += 4) {
448 ft = ff + s * (1 - d);
449 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
450 if (SameColor(board[rf][ff], board[rt][ft])) continue;
451 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
454 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
455 case SHOGI WhiteCardinal:
456 case SHOGI BlackCardinal:
459 /* Capablanca Archbishop continues as Knight */
464 /* Shogi Bishops are ordinary Bishops */
465 case SHOGI WhiteBishop:
466 case SHOGI BlackBishop:
469 for (rs = -1; rs <= 1; rs += 2)
470 for (fs = -1; fs <= 1; fs += 2)
474 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
475 if (SameColor(board[rf][ff], board[rt][ft])) break;
476 callback(board, flags, NormalMove,
477 rf, ff, rt, ft, closure);
478 if (board[rt][ft] != EmptySquare) break;
480 if(m==1) goto mounted;
481 if(m==2) goto finishGold;
482 /* Bishop falls through */
485 /* Shogi Lance is unlike anything, and asymmetric at that */
486 case SHOGI WhiteQueen:
490 if (rt >= BOARD_HEIGHT) break;
491 if (SameColor(board[rf][ff], board[rt][ft])) break;
492 callback(board, flags, NormalMove,
493 rf, ff, rt, ft, closure);
494 if (board[rt][ft] != EmptySquare) break;
498 case SHOGI BlackQueen:
503 if (SameColor(board[rf][ff], board[rt][ft])) break;
504 callback(board, flags, NormalMove,
505 rf, ff, rt, ft, closure);
506 if (board[rt][ft] != EmptySquare) break;
510 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
513 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
514 for (s = -2; s <= 2; s += 4) {
516 ft = ff + s * (1 - d);
517 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT || board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
518 if (SameColor(board[rf][ff], board[rt][ft])) continue;
519 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
521 if(gameInfo.variant == VariantSpartan) rookRange = 2; // in Spartan Chess restrict range to modern Dababba
524 /* Shogi Dragon King has to continue as Ferz after Rook moves */
525 case SHOGI WhiteDragon:
526 case SHOGI BlackDragon:
529 /* Capablanca Chancellor sets flag to continue as Knight */
533 m += (gameInfo.variant == VariantSpartan); // in Spartan Chess Chancellor is used for Dragon King.
535 /* Shogi Rooks are ordinary Rooks */
536 case SHOGI WhiteRook:
537 case SHOGI BlackRook:
541 for (d = 0; d <= 1; d++)
542 for (s = -1; s <= 1; s += 2)
544 rt = rf + (i * s) * d;
545 ft = ff + (i * s) * (1 - d);
546 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
547 if (SameColor(board[rf][ff], board[rt][ft])) break;
548 callback(board, flags, NormalMove,
549 rf, ff, rt, ft, closure);
550 if (board[rt][ft] != EmptySquare || i == rookRange) break;
552 if(m==1) goto mounted;
553 if(m==2) goto finishSilver;
558 for (rs = -1; rs <= 1; rs++)
559 for (fs = -1; fs <= 1; fs++) {
560 if (rs == 0 && fs == 0) continue;
564 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
565 if (SameColor(board[rf][ff], board[rt][ft])) break;
566 callback(board, flags, NormalMove,
567 rf, ff, rt, ft, closure);
568 if (board[rt][ft] != EmptySquare) break;
573 /* Shogi Pawn and Silver General: first the Pawn move, */
574 /* then the General continues like a Ferz */
576 if(gameInfo.variant != VariantMakruk) goto commoner;
577 case SHOGI WhitePawn:
578 case SHOGI WhiteFerz:
579 if (rf < BOARD_HEIGHT-1 &&
580 !SameColor(board[rf][ff], board[rf + 1][ff]) )
581 callback(board, flags, NormalMove,
582 rf, ff, rf + 1, ff, closure);
583 if(piece != SHOGI WhitePawn) goto finishSilver;
587 if(gameInfo.variant != VariantMakruk) goto commoner;
588 case SHOGI BlackPawn:
589 case SHOGI BlackFerz:
591 !SameColor(board[rf][ff], board[rf - 1][ff]) )
592 callback(board, flags, NormalMove,
593 rf, ff, rf - 1, ff, closure);
594 if(piece == SHOGI BlackPawn) break;
599 /* [HGM] support Shatranj pieces */
600 for (rs = -1; rs <= 1; rs += 2)
601 for (fs = -1; fs <= 1; fs += 2) {
604 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
605 if (!SameColor(board[rf][ff], board[rt][ft]) &&
606 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
607 callback(board, flags, NormalMove,
608 rf, ff, rt, ft, closure);
614 m++; // [HGM] superchess: use for Centaur
616 case SHOGI WhiteKing:
617 case SHOGI BlackKing:
621 for (i = -1; i <= 1; i++)
622 for (j = -1; j <= 1; j++) {
623 if (i == 0 && j == 0) continue;
626 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
627 if (SameColor(board[rf][ff], board[rt][ft])) continue;
628 callback(board, flags, NormalMove,
629 rf, ff, rt, ft, closure);
631 if(m==1) goto mounted;
634 case WhiteNightrider:
635 case BlackNightrider:
636 for (i = -1; i <= 1; i += 2)
637 for (j = -1; j <= 1; j += 2)
638 for (s = 1; s <= 2; s++) { int k;
642 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
643 if (SameColor(board[rf][ff], board[rt][ft])) break;
644 callback(board, flags, NormalMove,
645 rf, ff, rt, ft, closure);
646 if (board[rt][ft] != EmptySquare) break;
652 /* First do Bishop,then continue like Chancellor */
653 for (rs = -1; rs <= 1; rs += 2)
654 for (fs = -1; fs <= 1; fs += 2)
658 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
659 if (SameColor(board[rf][ff], board[rt][ft])) break;
660 callback(board, flags, NormalMove,
661 rf, ff, rt, ft, closure);
662 if (board[rt][ft] != EmptySquare) break;
667 // Use Lance as Berolina / Spartan Pawn.
669 if(gameInfo.variant == VariantSuper) goto Amazon;
670 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
671 callback(board, flags,
672 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
673 rf, ff, rf + 1, ff, closure);
674 for (s = -1; s <= 1; s += 2) {
675 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
676 callback(board, flags,
677 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
678 rf, ff, rf + 1, ff + s, closure);
679 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
680 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
685 if(gameInfo.variant == VariantSuper) goto Amazon;
686 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
687 callback(board, flags,
688 rf <= promoRank ? BlackPromotion : NormalMove,
689 rf, ff, rf - 1, ff, closure);
690 for (s = -1; s <= 1; s += 2) {
691 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
692 callback(board, flags,
693 rf <= promoRank ? BlackPromotion : NormalMove,
694 rf, ff, rf - 1, ff + s, closure);
695 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
696 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
700 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
704 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
717 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
719 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
720 int rf, int ff, int rt, int ft,
723 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
730 register GenLegalClosure *cl = (GenLegalClosure *) closure;
732 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
734 if (!(flags & F_IGNORE_CHECK) ) {
735 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
736 if(promo) board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
737 check = CheckTest(board, flags, rf, ff, rt, ft,
738 kind == WhiteCapturesEnPassant ||
739 kind == BlackCapturesEnPassant);
740 if(promo) board[rf][ff] = BlackLance;
743 if (flags & F_ATOMIC_CAPTURE) {
744 if (board[rt][ft] != EmptySquare ||
745 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
747 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
748 if (board[rf][ff] == king) return;
749 for (r = rt-1; r <= rt+1; r++) {
750 for (f = ft-1; f <= ft+1; f++) {
751 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
752 board[r][f] == king) return;
757 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
764 int captures; // [HGM] losers
765 } LegalityTestClosure;
768 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
769 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
770 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
771 moves that would destroy your own king. The CASTLE_OK flags are
772 true if castling is not yet ruled out by a move of the king or
773 rook. Return TRUE if the player on move is currently in check and
774 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
775 int GenLegal(board, flags, callback, closure, filter)
778 MoveCallback callback;
783 int ff, ft, k, left, right, swap;
784 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
785 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
789 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
790 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
793 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
795 /* Generate castling moves */
796 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
797 wKing = WhiteUnicorn; bKing = BlackUnicorn;
800 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
801 if ((flags & F_WHITE_ON_MOVE) &&
802 (flags & F_WHITE_KCASTLE_OK) &&
803 board[0][ff] == wKing &&
804 board[0][ff + 1] == EmptySquare &&
805 board[0][ff + 2] == EmptySquare &&
806 board[0][BOARD_RGHT-3] == EmptySquare &&
807 board[0][BOARD_RGHT-2] == EmptySquare &&
808 board[0][BOARD_RGHT-1] == WhiteRook &&
809 castlingRights[0] != NoRights && /* [HGM] check rights */
810 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
812 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
813 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
814 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
815 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
817 callback(board, flags,
818 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
819 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
821 if ((flags & F_WHITE_ON_MOVE) &&
822 (flags & F_WHITE_QCASTLE_OK) &&
823 board[0][ff] == wKing &&
824 board[0][ff - 1] == EmptySquare &&
825 board[0][ff - 2] == EmptySquare &&
826 board[0][BOARD_LEFT+2] == EmptySquare &&
827 board[0][BOARD_LEFT+1] == EmptySquare &&
828 board[0][BOARD_LEFT+0] == WhiteRook &&
829 castlingRights[1] != NoRights && /* [HGM] check rights */
830 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
832 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
833 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
834 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
836 callback(board, flags,
837 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
838 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
840 if (!(flags & F_WHITE_ON_MOVE) &&
841 (flags & F_BLACK_KCASTLE_OK) &&
842 board[BOARD_HEIGHT-1][ff] == bKing &&
843 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
844 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
845 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
846 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
847 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
848 castlingRights[3] != NoRights && /* [HGM] check rights */
849 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
851 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
852 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
853 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
854 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
856 callback(board, flags,
857 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
858 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
860 if (!(flags & F_WHITE_ON_MOVE) &&
861 (flags & F_BLACK_QCASTLE_OK) &&
862 board[BOARD_HEIGHT-1][ff] == bKing &&
863 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
864 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
865 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
866 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
867 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
868 castlingRights[4] != NoRights && /* [HGM] check rights */
869 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
871 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
872 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
873 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
875 callback(board, flags,
876 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
877 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
881 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
883 /* generate all potential FRC castling moves (KxR), ignoring flags */
884 /* [HGM] test if the Rooks we find have castling rights */
885 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
888 if ((flags & F_WHITE_ON_MOVE) != 0) {
889 ff = castlingRights[2]; /* King file if we have any rights */
890 if(ff != NoRights && board[0][ff] == WhiteKing) {
891 if (appData.debugMode) {
892 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
893 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
895 ft = castlingRights[0]; /* Rook file if we have H-side rights */
897 right = BOARD_RGHT-2;
898 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
899 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
900 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
901 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
902 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
903 if(ft != NoRights && board[0][ft] == WhiteRook)
904 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
906 ft = castlingRights[1]; /* Rook file if we have A-side rights */
909 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
910 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
911 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
912 if(ff > BOARD_LEFT+2)
913 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
914 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
915 if(ft != NoRights && board[0][ft] == WhiteRook)
916 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
919 ff = castlingRights[5]; /* King file if we have any rights */
920 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
921 ft = castlingRights[3]; /* Rook file if we have H-side rights */
923 right = BOARD_RGHT-2;
924 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
925 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
926 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
927 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
928 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
929 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
930 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
932 ft = castlingRights[4]; /* Rook file if we have A-side rights */
935 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
936 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
937 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
938 if(ff > BOARD_LEFT+2)
939 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
940 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
941 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
942 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
958 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
959 int rf, int ff, int rt, int ft,
963 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
970 register CheckTestClosure *cl = (CheckTestClosure *) closure;
972 if (rt == cl->rking && ft == cl->fking) cl->check++;
976 /* If the player on move were to move from (rf, ff) to (rt, ft), would
977 he leave himself in check? Or if rf == -1, is the player on move
978 in check now? enPassant must be TRUE if the indicated move is an
979 e.p. capture. The possibility of castling out of a check along the
980 back rank is not accounted for (i.e., we still return nonzero), as
981 this is illegal anyway. Return value is the number of times the
983 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
986 int rf, ff, rt, ft, enPassant;
989 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
990 ChessSquare captured = EmptySquare;
991 /* Suppress warnings on uninitialized variables */
993 if(gameInfo.variant == VariantXiangqi)
994 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
995 if(gameInfo.variant == VariantKnightmate)
996 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1000 captured = board[rf][ft];
1001 board[rf][ft] = EmptySquare;
1003 captured = board[rt][ft];
1005 board[rt][ft] = board[rf][ff];
1006 board[rf][ff] = EmptySquare;
1007 } else board[rt][ft] = ff; // [HGM] drop
1009 /* For compatibility with ICS wild 9, we scan the board in the
1010 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1011 and we test only whether that one is in check. */
1012 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1013 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1014 if (board[cl.rking][cl.fking] == king) {
1016 if(gameInfo.variant == VariantXiangqi) {
1017 /* [HGM] In Xiangqi opposing Kings means check as well */
1019 dir = (king >= BlackPawn) ? -1 : 1;
1020 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1021 board[i][cl.fking] == EmptySquare; i+=dir );
1022 if(i>=0 && i<BOARD_HEIGHT &&
1023 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1026 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1027 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1028 goto undo_move; /* 2-level break */
1035 board[rf][ff] = board[rt][ft];
1037 board[rf][ft] = captured;
1038 board[rt][ft] = EmptySquare;
1040 board[rt][ft] = captured;
1042 } else board[rt][ft] = EmptySquare; // [HGM] drop
1044 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1047 ChessMove LegalDrop(board, flags, piece, rt, ft)
1052 { // [HGM] put drop legality testing in separate routine for clarity
1054 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1055 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1056 n = PieceToNumber(piece);
1057 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1058 return ImpossibleMove; // piece not available
1059 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1060 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1061 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1062 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1063 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1064 if(piece == WhitePawn || piece == BlackPawn) {
1066 for(r=1; r<BOARD_HEIGHT-1; r++)
1067 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1068 // should still test if we mate with this Pawn
1070 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1071 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1073 if( (piece == WhitePawn || piece == BlackPawn) &&
1074 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1075 return IllegalMove; /* no pawn drops on 1st/8th */
1077 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1078 if (!(flags & F_IGNORE_CHECK) &&
1079 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1080 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1083 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1084 int rf, int ff, int rt, int ft,
1087 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1094 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1096 // if (appData.debugMode) {
1097 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1099 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1100 cl->captures++; // [HGM] losers: count legal captures
1101 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1105 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1108 int rf, ff, rt, ft, promoChar;
1110 LegalityTestClosure cl; ChessSquare piece, filterPiece, *castlingRights = board[CASTLING];
1112 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1113 piece = filterPiece = board[rf][ff];
1114 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1116 if (appData.debugMode) {
1118 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1119 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1121 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1122 /* (perhaps we should disallow moves that obviously leave us in check?) */
1123 if(piece == WhiteFalcon || piece == BlackFalcon ||
1124 piece == WhiteCobra || piece == BlackCobra)
1125 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1129 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1130 cl.ft = fFilter = ft;
1131 cl.kind = IllegalMove;
1132 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1133 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1134 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1135 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1136 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1137 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1139 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1140 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1141 if(board[rf][ff] < BlackPawn) { // white
1142 if(rf != 0) return IllegalMove; // must be on back rank
1143 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1145 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1146 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1149 if(gameInfo.variant == VariantShogi) {
1150 /* [HGM] Shogi promotions. '=' means defer */
1151 if(rf != DROP_RANK && cl.kind == NormalMove) {
1152 ChessSquare piece = board[rf][ff];
1154 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1155 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1156 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1157 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1158 promoChar = '+'; // allowed ICS notations
1159 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1160 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1161 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1162 else if(flags & F_WHITE_ON_MOVE) {
1163 if( (int) piece < (int) WhiteWazir &&
1164 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1165 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1166 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1167 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1168 else /* promotion optional, default is defer */
1169 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1170 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1172 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1173 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1174 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1175 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1176 else /* promotion optional, default is defer */
1177 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1178 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1182 if (promoChar != NULLCHAR) {
1183 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1184 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1185 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1186 if(piece == EmptySquare)
1187 cl.kind = ImpossibleMove; // non-existing piece
1188 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1189 if(promoChar != PieceToChar(BlackKing)) {
1190 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1191 if(piece == BlackLance) cl.kind = ImpossibleMove;
1192 } else { // promotion to King allowed only if we do not haave two yet
1193 int r, f, kings = 0;
1194 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1195 if(kings == 2) cl.kind = IllegalMove;
1197 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1198 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1199 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1200 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1201 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1202 cl.kind = IllegalMove; // promotion to King usually not allowed
1204 cl.kind = IllegalMove;
1214 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1215 int rf, int ff, int rt, int ft,
1218 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1225 register MateTestClosure *cl = (MateTestClosure *) closure;
1230 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1231 int MateTest(board, flags)
1236 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1237 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1239 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1240 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1241 nrKing += (board[r][f] == king); // stm has king
1242 if( board[r][f] != EmptySquare ) {
1243 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1248 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1249 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1250 case VariantShatranj:
1251 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1255 if(nrKing == 0) return MT_NOKING;
1258 if(myPieces == 1) return MT_BARE;
1261 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1262 // [HGM] 3check: yet to do!
1264 return inCheck ? MT_CHECK : MT_NONE;
1266 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1267 && gameInfo.variant != VariantGrand) { // drop game
1268 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1269 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1270 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1271 if(board[n][holdings] != EmptySquare) {
1272 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1273 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1276 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1277 return myPieces == hisPieces ? MT_STALEMATE :
1278 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1279 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1280 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1282 return inCheck ? MT_CHECKMATE
1283 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1284 MT_STAINMATE : MT_STALEMATE;
1289 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1290 int rf, int ff, int rt, int ft,
1293 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1300 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1301 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1303 // [HGM] wild: for wild-card pieces rt and rf are dummies
1304 if(piece == WhiteFalcon || piece == BlackFalcon ||
1305 piece == WhiteCobra || piece == BlackCobra)
1308 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1309 || PieceToChar(board[rf][ff]) == '~'
1310 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1312 (cl->rfIn == -1 || cl->rfIn == rf) &&
1313 (cl->ffIn == -1 || cl->ffIn == ff) &&
1314 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1315 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1318 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1319 // [HGM] oneclick: if multiple moves, be sure we remember capture
1320 cl->piece = board[rf][ff];
1323 cl->rt = wildCard ? cl->rtIn : rt;
1324 cl->ft = wildCard ? cl->ftIn : ft;
1327 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1331 void Disambiguate(board, flags, closure)
1334 DisambiguateClosure *closure;
1336 int illegal = 0; char c = closure->promoCharIn;
1338 closure->count = closure->captures = 0;
1339 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1340 closure->kind = ImpossibleMove;
1341 if (appData.debugMode) {
1342 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1343 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1344 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1346 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1347 fFilter = closure->ftIn;
1348 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1349 if (closure->count == 0) {
1350 /* See if it's an illegal move due to check */
1352 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1353 if (closure->count == 0) {
1354 /* No, it's not even that */
1355 if (appData.debugMode) { int i, j;
1356 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1357 for(j=0; j<BOARD_WIDTH; j++)
1358 fprintf(debugFP, "%3d", (int) board[i][j]);
1359 fprintf(debugFP, "\n");
1366 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1367 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1368 if(closure->piece < BlackPawn) { // white
1369 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1370 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1372 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1373 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1376 if(gameInfo.variant == VariantShogi) {
1377 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1378 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1379 ChessSquare piece = closure->piece;
1380 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1381 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1382 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1383 c = '+'; // allowed ICS notations
1384 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1385 else if(flags & F_WHITE_ON_MOVE) {
1386 if( (int) piece < (int) WhiteWazir &&
1387 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1388 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1389 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1390 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1391 else /* promotion optional, default is defer */
1392 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1393 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1395 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1396 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1397 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1398 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1399 else /* promotion optional, default is defer */
1400 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1401 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1404 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1405 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1407 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1408 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1409 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier || gameInfo.variant == VariantMakruk)
1410 c = PieceToChar(BlackFerz);
1411 else if(gameInfo.variant == VariantGreat)
1412 c = PieceToChar(BlackMan);
1413 else if(gameInfo.variant == VariantGrand)
1414 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1416 c = PieceToChar(BlackQueen);
1417 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1418 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1420 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1421 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1422 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1423 if (closure->count > 1) {
1424 closure->kind = AmbiguousMove;
1427 /* Note: If more than one illegal move matches, but no legal
1428 moves, we return IllegalMove, not AmbiguousMove. Caller
1429 can look at closure->count to detect this.
1431 closure->kind = IllegalMove;
1433 if (appData.debugMode) {
1434 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1435 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1436 closure->promoChar >= ' ' ? closure->promoChar:'-');
1450 } CoordsToAlgebraicClosure;
1452 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1453 ChessMove kind, int rf, int ff,
1454 int rt, int ft, VOIDSTAR closure));
1456 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1463 register CoordsToAlgebraicClosure *cl =
1464 (CoordsToAlgebraicClosure *) closure;
1466 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1467 (board[rf][ff] == cl->piece
1468 || PieceToChar(board[rf][ff]) == '~' &&
1469 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1473 cl->kind = kind; /* this is the move we want */
1475 cl->file++; /* need file to rule out this move */
1479 cl->rank++; /* need rank to rule out this move */
1481 cl->either++; /* rank or file will rule out this move */
1487 /* Convert coordinates to normal algebraic notation.
1488 promoChar must be NULLCHAR or 'x' if not a promotion.
1490 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1499 char *outp = out, c;
1500 CoordsToAlgebraicClosure cl;
1502 if (rf == DROP_RANK) {
1503 /* Bughouse piece drop */
1504 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1509 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1511 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1514 if (promoChar == 'x') promoChar = NULLCHAR;
1515 piece = board[rf][ff];
1516 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1518 if (appData.debugMode)
1519 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1523 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1524 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1525 /* Keep short notation if move is illegal only because it
1526 leaves the player in check, but still return IllegalMove */
1527 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1528 if (kind == IllegalMove) break;
1533 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1534 /* Non-capture; use style "e5" */
1537 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1539 /* Capture; use style "exd5" */
1540 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1541 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1545 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1547 /* Use promotion suffix style "=Q" */
1549 if (appData.debugMode)
1550 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1551 if (promoChar != NULLCHAR) {
1552 if(gameInfo.variant == VariantShogi) {
1553 /* [HGM] ... but not in Shogi! */
1554 *outp++ = promoChar == '=' ? '=' : '+';
1557 *outp++ = ToUpper(promoChar);
1566 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1567 /* Code added by Tord: FRC castling. */
1568 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1569 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1571 safeStrCpy(out, "O-O", MOVE_LEN);
1573 safeStrCpy(out, "O-O-O", MOVE_LEN);
1574 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1576 /* End of code added by Tord */
1577 /* Test for castling or ICS wild castling */
1578 /* Use style "O-O" (oh-oh) for PGN compatibility */
1579 else if (rf == rt &&
1580 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1581 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1582 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1583 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1584 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1585 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1587 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1589 /* This notation is always unambiguous, unless there are
1590 kings on both the d and e files, with "wild castling"
1591 possible for the king on the d file and normal castling
1592 possible for the other. ICS rules for wild 9
1593 effectively make castling illegal for either king in
1594 this situation. So I am not going to worry about it;
1595 I'll just generate an ambiguous O-O in this case.
1597 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1600 /* else fall through */
1605 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1606 cl.ft = fFilter = ft;
1608 cl.kind = IllegalMove;
1609 cl.rank = cl.file = cl.either = 0;
1610 c = PieceToChar(piece) ;
1611 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1613 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1614 /* Generate pretty moves for moving into check, but
1615 still return IllegalMove.
1617 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1618 if (cl.kind == IllegalMove) break;
1619 cl.kind = IllegalMove;
1622 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1623 else "Ngf3" or "Ngxf7",
1624 else "N1f3" or "N5xf7",
1625 else "Ng1f3" or "Ng5xf7".
1627 if( c == '~' || c == '+') {
1628 /* [HGM] print nonexistent piece as its demoted version */
1629 piece = (ChessSquare) (DEMOTED piece);
1631 if(c=='+') *outp++ = c;
1632 *outp++ = ToUpper(PieceToChar(piece));
1634 if (cl.file || (cl.either && !cl.rank)) {
1640 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1643 if(board[rt][ft] != EmptySquare)
1649 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1650 if (gameInfo.variant == VariantShogi) {
1651 /* [HGM] in Shogi non-pawns can promote */
1652 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1654 else if (gameInfo.variant != VariantSuper && promoChar &&
1655 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1657 *outp++ = ToUpper(promoChar);
1659 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1661 *outp++ = ToUpper(promoChar);
1667 /* Moving a nonexistent piece */
1671 /* Not a legal move, even ignoring check.
1672 If there was a piece on the from square,
1673 use style "Ng1g3" or "Ng1xe8";
1674 if there was a pawn or nothing (!),
1675 use style "g1g3" or "g1xe8". Use "x"
1676 if a piece was on the to square, even
1677 a piece of the same color.
1681 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1683 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1684 c += (board[r][f] == piece); // count on-board pieces of given type
1685 *outp++ = ToUpper(PieceToChar(piece));
1687 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1691 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1693 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1697 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1698 /* Use promotion suffix style "=Q" */
1699 if (promoChar != NULLCHAR && promoChar != 'x') {
1701 *outp++ = ToUpper(promoChar);
1708 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1717 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1719 int preyStackPointer, chaseStackPointer;
1722 unsigned char rf, ff, rt, ft;
1726 unsigned char rank, file;
1732 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1734 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1735 int rf, int ff, int rt, int ft,
1738 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1744 { // For adding captures that can lead to chase indictment to the chaseStack
1745 if(board[rt][ft] == EmptySquare) return; // non-capture
1746 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1747 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1748 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1749 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1750 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1751 chaseStack[chaseStackPointer].rf = rf;
1752 chaseStack[chaseStackPointer].ff = ff;
1753 chaseStack[chaseStackPointer].rt = rt;
1754 chaseStack[chaseStackPointer].ft = ft;
1755 chaseStackPointer++;
1758 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1759 int rf, int ff, int rt, int ft,
1762 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1768 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1770 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1772 if(board[rt][ft] == EmptySquare) return; // no capture
1773 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1774 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1776 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1777 for(i=0; i<chaseStackPointer; i++) {
1778 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1779 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1780 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1781 chaseStack[i] = chaseStack[--chaseStackPointer];
1787 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1788 int rf, int ff, int rt, int ft,
1791 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1797 { // for determining if a piece (given through the closure) is protected
1798 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1800 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1801 if(appData.debugMode && board[rt][ft] != EmptySquare)
1802 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1805 extern char moveList[MAX_MOVES][MOVE_LEN];
1807 int PerpetualChase(int first, int last)
1808 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1811 ChessSquare captured;
1813 preyStackPointer = 0; // clear stack of chased pieces
1814 for(i=first; i<last; i+=2) { // for all positions with same side to move
1815 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1816 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1817 // determine all captures possible after the move, and put them on chaseStack
1818 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1819 if(appData.debugMode) { int n;
1820 for(n=0; n<chaseStackPointer; n++)
1821 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1822 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1823 fprintf(debugFP, ": all capts\n");
1825 // determine all captures possible before the move, and delete them from chaseStack
1826 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1827 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1828 cl.rt = moveList[i][3]-ONE;
1829 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1830 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1831 if(appData.debugMode) { int n;
1832 for(n=0; n<chaseStackPointer; n++)
1833 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1834 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1835 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1837 // chaseSack now contains all captures made possible by the move
1838 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1839 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1840 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1842 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1843 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1845 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1846 continue; // C or H attack on R is always chase; leave on chaseStack
1848 if(attacker == victim) {
1849 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1850 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1851 // we can capture back with equal piece, so this is no chase but a sacrifice
1852 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1853 j--; /* ! */ continue;
1858 // the attack is on a lower piece, or on a pinned or blocked equal one
1859 // test if the victim is protected by a true protector. First make the capture.
1860 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1861 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1862 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1863 // Then test if the opponent can recapture
1864 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1865 cl.rt = chaseStack[j].rt;
1866 cl.ft = chaseStack[j].ft;
1867 if(appData.debugMode) {
1868 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1870 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1871 // unmake the capture
1872 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1873 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1874 // if a recapture was found, piece is protected, and we are not chasing it.
1875 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1876 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1880 // chaseStack now contains all moves that chased
1881 if(appData.debugMode) { int n;
1882 for(n=0; n<chaseStackPointer; n++)
1883 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1884 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1885 fprintf(debugFP, ": chases\n");
1887 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1888 for(j=0; j<chaseStackPointer; j++) {
1889 preyStack[j].rank = chaseStack[j].rt;
1890 preyStack[j].file = chaseStack[j].ft;
1892 preyStackPointer = chaseStackPointer;
1895 for(j=0; j<chaseStackPointer; j++) {
1896 for(k=0; k<preyStackPointer; k++) {
1897 // search the victim of each chase move on the preyStack (first occurrence)
1898 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1899 if(k < tail) break; // piece was already identified as still being chased
1900 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1901 preyStack[tail] = preyStack[k]; // by swapping
1902 preyStack[k] = preyStack[preyStackPointer];
1908 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1909 if(appData.debugMode) { int n;
1910 for(n=0; n<preyStackPointer; n++)
1911 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1912 fprintf(debugFP, "always chased upto ply %d\n", i);
1914 // now adjust the location of the chased pieces according to opponent move
1915 for(j=0; j<preyStackPointer; j++) {
1916 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1917 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1918 preyStack[j].rank = moveList[i+1][3]-ONE;
1919 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1924 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased