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;
88 int SameColor(piece1, piece2)
89 ChessSquare piece1, piece2;
91 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
92 (int) piece1 < (int) BlackPawn &&
93 (int) piece2 >= (int) WhitePawn &&
94 (int) piece2 < (int) BlackPawn)
95 || ((int) piece1 >= (int) BlackPawn &&
96 (int) piece1 < (int) EmptySquare &&
97 (int) piece2 >= (int) BlackPawn &&
98 (int) piece2 < (int) EmptySquare);
101 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn))
104 char pieceToChar[] = {
105 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
106 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
107 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
108 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
110 char pieceNickName[EmptySquare];
115 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
116 return pieceToChar[(int) p];
119 int PieceToNumber(p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
123 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
125 while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
129 ChessSquare CharToPiece(c)
133 if(c == '.') return EmptySquare;
134 for(i=0; i< (int) EmptySquare; i++)
135 if(pieceNickName[i] == c) return (ChessSquare) i;
136 for(i=0; i< (int) EmptySquare; i++)
137 if(pieceToChar[i] == c) return (ChessSquare) i;
141 void CopyBoard(to, from)
146 for (i = 0; i < BOARD_HEIGHT; i++)
147 for (j = 0; j < BOARD_WIDTH; j++)
148 to[i][j] = from[i][j];
149 for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
150 to[CASTLING][j] = from[CASTLING][j];
151 to[HOLDINGS_SET] = 0; // flag used in ICS play
154 int CompareBoards(board1, board2)
155 Board board1, board2;
159 for (i = 0; i < BOARD_HEIGHT; i++)
160 for (j = 0; j < BOARD_WIDTH; j++) {
161 if (board1[i][j] != board2[i][j])
168 /* Call callback once for each pseudo-legal move in the given
169 position, except castling moves. A move is pseudo-legal if it is
170 legal, or if it would be legal except that it leaves the king in
171 check. In the arguments, epfile is EP_NONE if the previous move
172 was not a double pawn push, or the file 0..7 if it was, or
173 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
174 Promotion moves generated are to Queen only.
176 void GenPseudoLegal(board, flags, callback, closure, filter)
179 MoveCallback callback;
181 ChessSquare filter; // [HGM] speed: only do moves with this piece type
184 int i, j, d, s, fs, rs, rt, ft, m;
185 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
186 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand ? 3 : 1;
188 for (rf = 0; rf < BOARD_HEIGHT; rf++)
189 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
193 if(board[rf][ff] == EmptySquare) continue;
194 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
196 m = 0; piece = board[rf][ff];
197 if(PieceToChar(piece) == '~')
198 piece = (ChessSquare) ( DEMOTED piece );
199 if(filter != EmptySquare && piece != filter) continue;
200 if(gameInfo.variant == VariantShogi)
201 piece = (ChessSquare) ( SHOGI piece );
203 switch ((int)piece) {
204 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
206 /* can't happen ([HGM] except for faries...) */
210 if(gameInfo.variant == VariantXiangqi) {
211 /* [HGM] capture and move straight ahead in Xiangqi */
212 if (rf < BOARD_HEIGHT-1 &&
213 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
214 callback(board, flags, NormalMove,
215 rf, ff, rf + 1, ff, closure);
217 /* and move sideways when across the river */
218 for (s = -1; s <= 1; s += 2) {
219 if (rf >= BOARD_HEIGHT>>1 &&
220 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
221 !WhitePiece(board[rf][ff+s]) ) {
222 callback(board, flags, NormalMove,
223 rf, ff, rf, ff+s, closure);
228 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
229 callback(board, flags,
230 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
231 rf, ff, rf + 1, ff, closure);
233 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
234 gameInfo.variant != VariantShatranj && /* [HGM] */
235 gameInfo.variant != VariantCourier && /* [HGM] */
236 board[rf+2][ff] == EmptySquare ) {
237 callback(board, flags, NormalMove,
238 rf, ff, rf+2, ff, closure);
240 for (s = -1; s <= 1; s += 2) {
241 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
242 ((flags & F_KRIEGSPIEL_CAPTURE) ||
243 BlackPiece(board[rf + 1][ff + s]))) {
244 callback(board, flags,
245 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
246 rf, ff, rf + 1, ff + s, closure);
248 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
249 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
250 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
251 board[rf][ff + s] == BlackPawn &&
252 board[rf+1][ff + s] == EmptySquare) {
253 callback(board, flags, WhiteCapturesEnPassant,
254 rf, ff, rf+1, ff + s, closure);
261 if(gameInfo.variant == VariantXiangqi) {
262 /* [HGM] capture straight ahead in Xiangqi */
263 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
264 callback(board, flags, NormalMove,
265 rf, ff, rf - 1, ff, closure);
267 /* and move sideways when across the river */
268 for (s = -1; s <= 1; s += 2) {
269 if (rf < BOARD_HEIGHT>>1 &&
270 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
271 !BlackPiece(board[rf][ff+s]) ) {
272 callback(board, flags, NormalMove,
273 rf, ff, rf, ff+s, closure);
278 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
279 callback(board, flags,
280 rf <= promoRank ? BlackPromotion : NormalMove,
281 rf, ff, rf - 1, ff, closure);
283 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
284 gameInfo.variant != VariantShatranj && /* [HGM] */
285 gameInfo.variant != VariantCourier && /* [HGM] */
286 board[rf-2][ff] == EmptySquare) {
287 callback(board, flags, NormalMove,
288 rf, ff, rf-2, ff, closure);
290 for (s = -1; s <= 1; s += 2) {
291 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
292 ((flags & F_KRIEGSPIEL_CAPTURE) ||
293 WhitePiece(board[rf - 1][ff + s]))) {
294 callback(board, flags,
295 rf <= promoRank ? BlackPromotion : NormalMove,
296 rf, ff, rf - 1, ff + s, closure);
298 if (rf < BOARD_HEIGHT>>1) {
299 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
300 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
301 board[rf][ff + s] == WhitePawn &&
302 board[rf-1][ff + s] == EmptySquare) {
303 callback(board, flags, BlackCapturesEnPassant,
304 rf, ff, rf-1, ff + s, closure);
315 for (i = -1; i <= 1; i += 2)
316 for (j = -1; j <= 1; j += 2)
317 for (s = 1; s <= 2; s++) {
320 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
321 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
322 && !SameColor(board[rf][ff], board[rt][ft]))
323 callback(board, flags, NormalMove,
324 rf, ff, rt, ft, closure);
328 case SHOGI WhiteKnight:
329 for (s = -1; s <= 1; s += 2) {
330 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
331 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
332 callback(board, flags, NormalMove,
333 rf, ff, rf + 2, ff + s, closure);
338 case SHOGI BlackKnight:
339 for (s = -1; s <= 1; s += 2) {
340 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
341 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
342 callback(board, flags, NormalMove,
343 rf, ff, rf - 2, ff + s, closure);
350 for (d = 0; d <= 1; d++)
351 for (s = -1; s <= 1; s += 2) {
354 rt = rf + (i * s) * d;
355 ft = ff + (i * s) * (1 - d);
356 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
357 if (m == 0 && board[rt][ft] == EmptySquare)
358 callback(board, flags, NormalMove,
359 rf, ff, rt, ft, closure);
360 if (m == 1 && board[rt][ft] != EmptySquare &&
361 !SameColor(board[rf][ff], board[rt][ft]) )
362 callback(board, flags, NormalMove,
363 rf, ff, rt, ft, closure);
364 if (board[rt][ft] != EmptySquare && m++) break;
369 /* Gold General (and all its promoted versions) . First do the */
370 /* diagonal forward steps, then proceed as normal Wazir */
371 case SHOGI WhiteWazir:
372 case SHOGI (PROMOTED WhitePawn):
373 case SHOGI (PROMOTED WhiteKnight):
374 case SHOGI (PROMOTED WhiteQueen):
375 case SHOGI (PROMOTED WhiteFerz):
376 for (s = -1; s <= 1; s += 2) {
377 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
378 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
379 callback(board, flags, NormalMove,
380 rf, ff, rf + 1, ff + s, closure);
385 case SHOGI BlackWazir:
386 case SHOGI (PROMOTED BlackPawn):
387 case SHOGI (PROMOTED BlackKnight):
388 case SHOGI (PROMOTED BlackQueen):
389 case SHOGI (PROMOTED BlackFerz):
390 for (s = -1; s <= 1; s += 2) {
391 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
392 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
393 callback(board, flags, NormalMove,
394 rf, ff, rf - 1, ff + s, closure);
401 for (d = 0; d <= 1; d++)
402 for (s = -1; s <= 1; s += 2) {
404 ft = ff + s * (1 - d);
405 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
406 && !SameColor(board[rf][ff], board[rt][ft]) &&
407 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
408 callback(board, flags, NormalMove,
409 rf, ff, rt, ft, closure);
415 /* [HGM] support Shatranj pieces */
416 for (rs = -1; rs <= 1; rs += 2)
417 for (fs = -1; fs <= 1; fs += 2) {
420 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
421 && ( gameInfo.variant != VariantXiangqi ||
422 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
424 && !SameColor(board[rf][ff], board[rt][ft]))
425 callback(board, flags, NormalMove,
426 rf, ff, rt, ft, closure);
427 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier
428 || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
429 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
431 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
432 && !SameColor(board[rf][ff], board[rt][ft]))
433 callback(board, flags, NormalMove,
434 rf, ff, rt, ft, closure);
436 if(gameInfo.variant == VariantSpartan)
437 for(fs = -1; fs <= 1; fs += 2) {
439 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
440 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
444 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
447 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
448 for (s = -2; s <= 2; s += 4) {
450 ft = ff + s * (1 - d);
451 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
452 if (SameColor(board[rf][ff], board[rt][ft])) continue;
453 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
456 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
457 case SHOGI WhiteCardinal:
458 case SHOGI BlackCardinal:
461 /* Capablanca Archbishop continues as Knight */
466 /* Shogi Bishops are ordinary Bishops */
467 case SHOGI WhiteBishop:
468 case SHOGI BlackBishop:
471 for (rs = -1; rs <= 1; rs += 2)
472 for (fs = -1; fs <= 1; fs += 2)
476 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
477 if (SameColor(board[rf][ff], board[rt][ft])) break;
478 callback(board, flags, NormalMove,
479 rf, ff, rt, ft, closure);
480 if (board[rt][ft] != EmptySquare) break;
482 if(m==1) goto mounted;
483 if(m==2) goto finishGold;
484 /* Bishop falls through */
487 /* Shogi Lance is unlike anything, and asymmetric at that */
488 case SHOGI WhiteQueen:
492 if (rt >= BOARD_HEIGHT) break;
493 if (SameColor(board[rf][ff], board[rt][ft])) break;
494 callback(board, flags, NormalMove,
495 rf, ff, rt, ft, closure);
496 if (board[rt][ft] != EmptySquare) break;
500 case SHOGI BlackQueen:
505 if (SameColor(board[rf][ff], board[rt][ft])) break;
506 callback(board, flags, NormalMove,
507 rf, ff, rt, ft, closure);
508 if (board[rt][ft] != EmptySquare) break;
512 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
515 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
516 for (s = -2; s <= 2; s += 4) {
518 ft = ff + s * (1 - d);
519 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT || board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
520 if (SameColor(board[rf][ff], board[rt][ft])) continue;
521 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
523 if(gameInfo.variant == VariantSpartan) rookRange = 2; // in Spartan Chess restrict range to modern Dababba
526 /* Shogi Dragon King has to continue as Ferz after Rook moves */
527 case SHOGI WhiteDragon:
528 case SHOGI BlackDragon:
531 /* Capablanca Chancellor sets flag to continue as Knight */
535 m += (gameInfo.variant == VariantSpartan); // in Spartan Chess Chancellor is used for Dragon King.
537 /* Shogi Rooks are ordinary Rooks */
538 case SHOGI WhiteRook:
539 case SHOGI BlackRook:
543 for (d = 0; d <= 1; d++)
544 for (s = -1; s <= 1; s += 2)
546 rt = rf + (i * s) * d;
547 ft = ff + (i * s) * (1 - d);
548 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
549 if (SameColor(board[rf][ff], board[rt][ft])) break;
550 callback(board, flags, NormalMove,
551 rf, ff, rt, ft, closure);
552 if (board[rt][ft] != EmptySquare || i == rookRange) break;
554 if(m==1) goto mounted;
555 if(m==2) goto finishSilver;
560 for (rs = -1; rs <= 1; rs++)
561 for (fs = -1; fs <= 1; fs++) {
562 if (rs == 0 && fs == 0) continue;
566 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
567 if (SameColor(board[rf][ff], board[rt][ft])) break;
568 callback(board, flags, NormalMove,
569 rf, ff, rt, ft, closure);
570 if (board[rt][ft] != EmptySquare) break;
575 /* Shogi Pawn and Silver General: first the Pawn move, */
576 /* then the General continues like a Ferz */
578 if(gameInfo.variant != VariantMakruk) goto commoner;
579 case SHOGI WhitePawn:
580 case SHOGI WhiteFerz:
581 if (rf < BOARD_HEIGHT-1 &&
582 !SameColor(board[rf][ff], board[rf + 1][ff]) )
583 callback(board, flags, NormalMove,
584 rf, ff, rf + 1, ff, closure);
585 if(piece != SHOGI WhitePawn) goto finishSilver;
589 if(gameInfo.variant != VariantMakruk) goto commoner;
590 case SHOGI BlackPawn:
591 case SHOGI BlackFerz:
593 !SameColor(board[rf][ff], board[rf - 1][ff]) )
594 callback(board, flags, NormalMove,
595 rf, ff, rf - 1, ff, closure);
596 if(piece == SHOGI BlackPawn) break;
601 /* [HGM] support Shatranj pieces */
602 for (rs = -1; rs <= 1; rs += 2)
603 for (fs = -1; fs <= 1; fs += 2) {
606 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
607 if (!SameColor(board[rf][ff], board[rt][ft]) &&
608 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
609 callback(board, flags, NormalMove,
610 rf, ff, rt, ft, closure);
616 m++; // [HGM] superchess: use for Centaur
618 case SHOGI WhiteKing:
619 case SHOGI BlackKing:
623 for (i = -1; i <= 1; i++)
624 for (j = -1; j <= 1; j++) {
625 if (i == 0 && j == 0) continue;
628 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
629 if (SameColor(board[rf][ff], board[rt][ft])) continue;
630 callback(board, flags, NormalMove,
631 rf, ff, rt, ft, closure);
633 if(m==1) goto mounted;
636 case WhiteNightrider:
637 case BlackNightrider:
638 for (i = -1; i <= 1; i += 2)
639 for (j = -1; j <= 1; j += 2)
640 for (s = 1; s <= 2; s++) { int k;
644 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
645 if (SameColor(board[rf][ff], board[rt][ft])) break;
646 callback(board, flags, NormalMove,
647 rf, ff, rt, ft, closure);
648 if (board[rt][ft] != EmptySquare) break;
654 /* First do Bishop,then continue like Chancellor */
655 for (rs = -1; rs <= 1; rs += 2)
656 for (fs = -1; fs <= 1; fs += 2)
660 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
661 if (SameColor(board[rf][ff], board[rt][ft])) break;
662 callback(board, flags, NormalMove,
663 rf, ff, rt, ft, closure);
664 if (board[rt][ft] != EmptySquare) break;
669 // Use Lance as Berolina / Spartan Pawn.
671 if(gameInfo.variant == VariantSuper) goto Amazon;
672 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
673 callback(board, flags,
674 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
675 rf, ff, rf + 1, ff, closure);
676 for (s = -1; s <= 1; s += 2) {
677 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
678 callback(board, flags,
679 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
680 rf, ff, rf + 1, ff + s, closure);
681 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
682 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
687 if(gameInfo.variant == VariantSuper) goto Amazon;
688 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
689 callback(board, flags,
690 rf <= promoRank ? BlackPromotion : NormalMove,
691 rf, ff, rf - 1, ff, closure);
692 for (s = -1; s <= 1; s += 2) {
693 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
694 callback(board, flags,
695 rf <= promoRank ? BlackPromotion : NormalMove,
696 rf, ff, rf - 1, ff + s, closure);
697 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
698 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
702 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
706 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
719 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
720 Board xqCheckers, nullBoard;
722 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
723 int rf, int ff, int rt, int ft,
726 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
733 register GenLegalClosure *cl = (GenLegalClosure *) closure;
735 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
737 if (!(flags & F_IGNORE_CHECK) ) {
738 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
741 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
742 kings += (board[r][f] == BlackKing);
746 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
748 check = CheckTest(board, flags, rf, ff, rt, ft,
749 kind == WhiteCapturesEnPassant ||
750 kind == BlackCapturesEnPassant);
751 if(promo) board[rf][ff] = BlackLance;
754 if (flags & F_ATOMIC_CAPTURE) {
755 if (board[rt][ft] != EmptySquare ||
756 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
758 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
759 if (board[rf][ff] == king) return;
760 for (r = rt-1; r <= rt+1; r++) {
761 for (f = ft-1; f <= ft+1; f++) {
762 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
763 board[r][f] == king) return;
768 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
775 int captures; // [HGM] losers
776 } LegalityTestClosure;
779 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
780 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
781 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
782 moves that would destroy your own king. The CASTLE_OK flags are
783 true if castling is not yet ruled out by a move of the king or
784 rook. Return TRUE if the player on move is currently in check and
785 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
786 int GenLegal(board, flags, callback, closure, filter)
789 MoveCallback callback;
794 int ff, ft, k, left, right, swap;
795 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
796 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
797 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
801 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
802 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
803 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
805 if (inCheck) return TRUE;
807 /* Generate castling moves */
808 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
809 wKing = WhiteUnicorn; bKing = BlackUnicorn;
812 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
813 if ((flags & F_WHITE_ON_MOVE) &&
814 (flags & F_WHITE_KCASTLE_OK) &&
815 board[0][ff] == wKing &&
816 board[0][ff + 1] == EmptySquare &&
817 board[0][ff + 2] == EmptySquare &&
818 board[0][BOARD_RGHT-3] == EmptySquare &&
819 board[0][BOARD_RGHT-2] == EmptySquare &&
820 board[0][BOARD_RGHT-1] == WhiteRook &&
821 castlingRights[0] != NoRights && /* [HGM] check rights */
822 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
824 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
825 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
826 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
827 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
829 callback(board, flags,
830 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
831 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
833 if ((flags & F_WHITE_ON_MOVE) &&
834 (flags & F_WHITE_QCASTLE_OK) &&
835 board[0][ff] == wKing &&
836 board[0][ff - 1] == EmptySquare &&
837 board[0][ff - 2] == EmptySquare &&
838 board[0][BOARD_LEFT+2] == EmptySquare &&
839 board[0][BOARD_LEFT+1] == EmptySquare &&
840 board[0][BOARD_LEFT+0] == WhiteRook &&
841 castlingRights[1] != NoRights && /* [HGM] check rights */
842 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
844 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
845 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
846 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
848 callback(board, flags,
849 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
850 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
852 if (!(flags & F_WHITE_ON_MOVE) &&
853 (flags & F_BLACK_KCASTLE_OK) &&
854 board[BOARD_HEIGHT-1][ff] == bKing &&
855 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
856 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
857 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
858 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
859 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
860 castlingRights[3] != NoRights && /* [HGM] check rights */
861 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
863 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
864 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
865 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
866 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
868 callback(board, flags,
869 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
870 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
872 if (!(flags & F_WHITE_ON_MOVE) &&
873 (flags & F_BLACK_QCASTLE_OK) &&
874 board[BOARD_HEIGHT-1][ff] == bKing &&
875 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
876 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
877 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
878 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
879 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
880 castlingRights[4] != NoRights && /* [HGM] check rights */
881 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
883 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
884 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
885 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
887 callback(board, flags,
888 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
889 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
893 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
895 /* generate all potential FRC castling moves (KxR), ignoring flags */
896 /* [HGM] test if the Rooks we find have castling rights */
897 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
900 if ((flags & F_WHITE_ON_MOVE) != 0) {
901 ff = castlingRights[2]; /* King file if we have any rights */
902 if(ff != NoRights && board[0][ff] == WhiteKing) {
903 if (appData.debugMode) {
904 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
905 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
907 ft = castlingRights[0]; /* Rook file if we have H-side rights */
909 right = BOARD_RGHT-2;
910 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
911 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
912 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
913 for(k=left; 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, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
918 ft = castlingRights[1]; /* Rook file if we have A-side rights */
921 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
922 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
923 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
924 if(ff > BOARD_LEFT+2)
925 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
926 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
927 if(ft != NoRights && board[0][ft] == WhiteRook)
928 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
931 ff = castlingRights[5]; /* King file if we have any rights */
932 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
933 ft = castlingRights[3]; /* Rook file if we have H-side rights */
935 right = BOARD_RGHT-2;
936 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
937 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
938 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
939 for(k=left; 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, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
944 ft = castlingRights[4]; /* Rook file if we have A-side rights */
947 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
948 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
949 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
950 if(ff > BOARD_LEFT+2)
951 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
952 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
953 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
954 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
970 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
971 int rf, int ff, int rt, int ft,
975 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
982 register CheckTestClosure *cl = (CheckTestClosure *) closure;
984 if (rt == cl->rking && ft == cl->fking) {
985 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
987 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
992 /* If the player on move were to move from (rf, ff) to (rt, ft), would
993 he leave himself in check? Or if rf == -1, is the player on move
994 in check now? enPassant must be TRUE if the indicated move is an
995 e.p. capture. The possibility of castling out of a check along the
996 back rank is not accounted for (i.e., we still return nonzero), as
997 this is illegal anyway. Return value is the number of times the
999 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
1002 int rf, ff, rt, ft, enPassant;
1004 CheckTestClosure cl;
1005 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1006 ChessSquare captured = EmptySquare;
1007 /* Suppress warnings on uninitialized variables */
1009 if(gameInfo.variant == VariantXiangqi)
1010 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1011 if(gameInfo.variant == VariantKnightmate)
1012 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1016 captured = board[rf][ft];
1017 board[rf][ft] = EmptySquare;
1019 captured = board[rt][ft];
1021 board[rt][ft] = board[rf][ff];
1022 board[rf][ff] = EmptySquare;
1023 } else board[rt][ft] = ff; // [HGM] drop
1025 /* For compatibility with ICS wild 9, we scan the board in the
1026 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1027 and we test only whether that one is in check. */
1028 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1029 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1030 if (board[cl.rking][cl.fking] == king) {
1032 if(gameInfo.variant == VariantXiangqi) {
1033 /* [HGM] In Xiangqi opposing Kings means check as well */
1035 dir = (king >= BlackPawn) ? -1 : 1;
1036 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1037 board[i][cl.fking] == EmptySquare; i+=dir );
1038 if(i>=0 && i<BOARD_HEIGHT &&
1039 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1042 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1043 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1044 goto undo_move; /* 2-level break */
1051 board[rf][ff] = board[rt][ft];
1053 board[rf][ft] = captured;
1054 board[rt][ft] = EmptySquare;
1056 board[rt][ft] = captured;
1058 } else board[rt][ft] = EmptySquare; // [HGM] drop
1060 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1063 ChessMove LegalDrop(board, flags, piece, rt, ft)
1068 { // [HGM] put drop legality testing in separate routine for clarity
1070 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1071 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1072 n = PieceToNumber(piece);
1073 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1074 return ImpossibleMove; // piece not available
1075 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1076 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1077 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1078 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1079 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1080 if(piece == WhitePawn || piece == BlackPawn) {
1082 for(r=1; r<BOARD_HEIGHT-1; r++)
1083 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1084 // should still test if we mate with this Pawn
1086 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1087 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1089 if( (piece == WhitePawn || piece == BlackPawn) &&
1090 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1091 return IllegalMove; /* no pawn drops on 1st/8th */
1093 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1094 if (!(flags & F_IGNORE_CHECK) &&
1095 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1096 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1099 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1100 int rf, int ff, int rt, int ft,
1103 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1110 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1112 // if (appData.debugMode) {
1113 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1115 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1116 cl->captures++; // [HGM] losers: count legal captures
1117 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1121 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1124 int rf, ff, rt, ft, promoChar;
1126 LegalityTestClosure cl; ChessSquare piece, filterPiece, *castlingRights = board[CASTLING];
1128 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1129 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1130 piece = filterPiece = board[rf][ff];
1131 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1133 if (appData.debugMode) {
1135 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1136 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1138 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1139 /* (perhaps we should disallow moves that obviously leave us in check?) */
1140 if(piece == WhiteFalcon || piece == BlackFalcon ||
1141 piece == WhiteCobra || piece == BlackCobra)
1142 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1146 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1147 cl.ft = fFilter = ft;
1148 cl.kind = IllegalMove;
1149 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1150 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1151 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1152 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1153 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1154 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1156 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1157 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1158 if(board[rf][ff] < BlackPawn) { // white
1159 if(rf != 0) return IllegalMove; // must be on back rank
1160 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1162 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1163 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1166 if(gameInfo.variant == VariantShogi) {
1167 /* [HGM] Shogi promotions. '=' means defer */
1168 if(rf != DROP_RANK && cl.kind == NormalMove) {
1169 ChessSquare piece = board[rf][ff];
1171 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1172 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1173 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1174 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1175 promoChar = '+'; // allowed ICS notations
1176 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1177 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1178 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1179 else if(flags & F_WHITE_ON_MOVE) {
1180 if( (int) piece < (int) WhiteWazir &&
1181 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1182 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1183 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1184 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1185 else /* promotion optional, default is defer */
1186 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1187 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1189 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1190 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1191 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1192 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1193 else /* promotion optional, default is defer */
1194 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1195 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1199 if (promoChar != NULLCHAR) {
1200 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1201 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1202 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1203 if(piece == EmptySquare)
1204 cl.kind = ImpossibleMove; // non-existing piece
1205 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1206 if(promoChar != PieceToChar(BlackKing)) {
1207 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1208 if(piece == BlackLance) cl.kind = ImpossibleMove;
1209 } else { // promotion to King allowed only if we do not haave two yet
1210 int r, f, kings = 0;
1211 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1212 if(kings == 2) cl.kind = IllegalMove;
1214 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1215 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1216 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1217 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1218 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1219 cl.kind = IllegalMove; // promotion to King usually not allowed
1221 cl.kind = IllegalMove;
1231 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1232 int rf, int ff, int rt, int ft,
1235 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1242 register MateTestClosure *cl = (MateTestClosure *) closure;
1247 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1248 int MateTest(board, flags)
1253 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1254 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1256 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1257 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1258 nrKing += (board[r][f] == king); // stm has king
1259 if( board[r][f] != EmptySquare ) {
1260 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1265 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1266 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1267 case VariantShatranj:
1268 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1272 if(nrKing == 0) return MT_NOKING;
1275 if(myPieces == 1) return MT_BARE;
1278 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1279 // [HGM] 3check: yet to do!
1281 return inCheck ? MT_CHECK : MT_NONE;
1283 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1284 && gameInfo.variant != VariantGrand) { // drop game
1285 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1286 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1287 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1288 if(board[n][holdings] != EmptySquare) {
1289 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1290 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1293 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1294 return myPieces == hisPieces ? MT_STALEMATE :
1295 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1296 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1297 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1299 return inCheck ? MT_CHECKMATE
1300 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1301 MT_STAINMATE : MT_STALEMATE;
1306 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1307 int rf, int ff, int rt, int ft,
1310 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1317 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1318 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1320 // [HGM] wild: for wild-card pieces rt and rf are dummies
1321 if(piece == WhiteFalcon || piece == BlackFalcon ||
1322 piece == WhiteCobra || piece == BlackCobra)
1325 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1326 || PieceToChar(board[rf][ff]) == '~'
1327 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1329 (cl->rfIn == -1 || cl->rfIn == rf) &&
1330 (cl->ffIn == -1 || cl->ffIn == ff) &&
1331 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1332 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1335 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1336 // [HGM] oneclick: if multiple moves, be sure we remember capture
1337 cl->piece = board[rf][ff];
1340 cl->rt = wildCard ? cl->rtIn : rt;
1341 cl->ft = wildCard ? cl->ftIn : ft;
1344 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1348 void Disambiguate(board, flags, closure)
1351 DisambiguateClosure *closure;
1353 int illegal = 0; char c = closure->promoCharIn;
1355 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1356 closure->count = closure->captures = 0;
1357 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1358 closure->kind = ImpossibleMove;
1359 if (appData.debugMode) {
1360 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1361 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1362 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1364 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1365 fFilter = closure->ftIn;
1366 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1367 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1368 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1369 closure->count = closure->captures = 0;
1370 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1371 closure->kind = ImpossibleMove;
1372 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1375 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1376 if (closure->count == 0) {
1377 /* See if it's an illegal move due to check */
1379 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1380 if (closure->count == 0) {
1381 /* No, it's not even that */
1382 if (appData.debugMode) { int i, j;
1383 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1384 for(j=0; j<BOARD_WIDTH; j++)
1385 fprintf(debugFP, "%3d", (int) board[i][j]);
1386 fprintf(debugFP, "\n");
1393 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1394 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1395 if(closure->piece < BlackPawn) { // white
1396 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1397 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1399 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1400 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1403 if(gameInfo.variant == VariantShogi) {
1404 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1405 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1406 ChessSquare piece = closure->piece;
1407 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1408 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1409 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1410 c = '+'; // allowed ICS notations
1411 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1412 else if(flags & F_WHITE_ON_MOVE) {
1413 if( (int) piece < (int) WhiteWazir &&
1414 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1415 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1416 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1417 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1418 else /* promotion optional, default is defer */
1419 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1420 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1422 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1423 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1424 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1425 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1426 else /* promotion optional, default is defer */
1427 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1428 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1431 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1432 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1434 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1435 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1436 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier || gameInfo.variant == VariantMakruk)
1437 c = PieceToChar(BlackFerz);
1438 else if(gameInfo.variant == VariantGreat)
1439 c = PieceToChar(BlackMan);
1440 else if(gameInfo.variant == VariantGrand)
1441 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1443 c = PieceToChar(BlackQueen);
1444 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1445 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1447 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1448 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1449 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1450 if (closure->count > 1) {
1451 closure->kind = AmbiguousMove;
1454 /* Note: If more than one illegal move matches, but no legal
1455 moves, we return IllegalMove, not AmbiguousMove. Caller
1456 can look at closure->count to detect this.
1458 closure->kind = IllegalMove;
1460 if (appData.debugMode) {
1461 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1462 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1463 closure->promoChar >= ' ' ? closure->promoChar:'-');
1477 } CoordsToAlgebraicClosure;
1479 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1480 ChessMove kind, int rf, int ff,
1481 int rt, int ft, VOIDSTAR closure));
1483 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1490 register CoordsToAlgebraicClosure *cl =
1491 (CoordsToAlgebraicClosure *) closure;
1493 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1494 (board[rf][ff] == cl->piece
1495 || PieceToChar(board[rf][ff]) == '~' &&
1496 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1500 cl->kind = kind; /* this is the move we want */
1502 cl->file++; /* need file to rule out this move */
1506 cl->rank++; /* need rank to rule out this move */
1508 cl->either++; /* rank or file will rule out this move */
1514 /* Convert coordinates to normal algebraic notation.
1515 promoChar must be NULLCHAR or 'x' if not a promotion.
1517 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1526 char *outp = out, c;
1527 CoordsToAlgebraicClosure cl;
1529 if (rf == DROP_RANK) {
1530 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
1531 /* Bughouse piece drop */
1532 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1537 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1539 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1542 if (promoChar == 'x') promoChar = NULLCHAR;
1543 piece = board[rf][ff];
1544 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1546 if (appData.debugMode)
1547 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1551 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1552 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1553 /* Keep short notation if move is illegal only because it
1554 leaves the player in check, but still return IllegalMove */
1555 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1556 if (kind == IllegalMove) break;
1561 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1562 /* Non-capture; use style "e5" */
1565 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1567 /* Capture; use style "exd5" */
1568 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1569 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1573 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1575 /* Use promotion suffix style "=Q" */
1577 if (appData.debugMode)
1578 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1579 if (promoChar != NULLCHAR) {
1580 if(gameInfo.variant == VariantShogi) {
1581 /* [HGM] ... but not in Shogi! */
1582 *outp++ = promoChar == '=' ? '=' : '+';
1585 *outp++ = ToUpper(promoChar);
1594 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1595 /* Code added by Tord: FRC castling. */
1596 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1597 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1599 safeStrCpy(out, "O-O", MOVE_LEN);
1601 safeStrCpy(out, "O-O-O", MOVE_LEN);
1602 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1604 /* End of code added by Tord */
1605 /* Test for castling or ICS wild castling */
1606 /* Use style "O-O" (oh-oh) for PGN compatibility */
1607 else if (rf == rt &&
1608 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1609 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1610 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1611 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1612 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1613 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1615 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1617 /* This notation is always unambiguous, unless there are
1618 kings on both the d and e files, with "wild castling"
1619 possible for the king on the d file and normal castling
1620 possible for the other. ICS rules for wild 9
1621 effectively make castling illegal for either king in
1622 this situation. So I am not going to worry about it;
1623 I'll just generate an ambiguous O-O in this case.
1625 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1628 /* else fall through */
1633 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1634 cl.ft = fFilter = ft;
1636 cl.kind = IllegalMove;
1637 cl.rank = cl.file = cl.either = 0;
1638 c = PieceToChar(piece) ;
1639 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1641 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1642 /* Generate pretty moves for moving into check, but
1643 still return IllegalMove.
1645 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1646 if (cl.kind == IllegalMove) break;
1647 cl.kind = IllegalMove;
1650 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1651 else "Ngf3" or "Ngxf7",
1652 else "N1f3" or "N5xf7",
1653 else "Ng1f3" or "Ng5xf7".
1655 if( c == '~' || c == '+') {
1656 /* [HGM] print nonexistent piece as its demoted version */
1657 piece = (ChessSquare) (DEMOTED piece);
1659 if(c=='+') *outp++ = c;
1660 *outp++ = ToUpper(PieceToChar(piece));
1662 if (cl.file || (cl.either && !cl.rank)) {
1668 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1671 if(board[rt][ft] != EmptySquare)
1677 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1678 if (gameInfo.variant == VariantShogi) {
1679 /* [HGM] in Shogi non-pawns can promote */
1680 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1682 else if (gameInfo.variant != VariantSuper && promoChar &&
1683 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1685 *outp++ = ToUpper(promoChar);
1687 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1689 *outp++ = ToUpper(promoChar);
1695 /* Moving a nonexistent piece */
1699 /* Not a legal move, even ignoring check.
1700 If there was a piece on the from square,
1701 use style "Ng1g3" or "Ng1xe8";
1702 if there was a pawn or nothing (!),
1703 use style "g1g3" or "g1xe8". Use "x"
1704 if a piece was on the to square, even
1705 a piece of the same color.
1709 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1711 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1712 c += (board[r][f] == piece); // count on-board pieces of given type
1713 *outp++ = ToUpper(PieceToChar(piece));
1715 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1719 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1721 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1725 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1726 /* Use promotion suffix style "=Q" */
1727 if (promoChar != NULLCHAR && promoChar != 'x') {
1729 *outp++ = ToUpper(promoChar);
1736 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1745 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1747 int preyStackPointer, chaseStackPointer;
1750 unsigned char rf, ff, rt, ft;
1754 unsigned char rank, file;
1760 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1762 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1763 int rf, int ff, int rt, int ft,
1766 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1772 { // For adding captures that can lead to chase indictment to the chaseStack
1773 if(board[rt][ft] == EmptySquare) return; // non-capture
1774 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1775 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1776 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1777 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1778 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1779 chaseStack[chaseStackPointer].rf = rf;
1780 chaseStack[chaseStackPointer].ff = ff;
1781 chaseStack[chaseStackPointer].rt = rt;
1782 chaseStack[chaseStackPointer].ft = ft;
1783 chaseStackPointer++;
1786 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1787 int rf, int ff, int rt, int ft,
1790 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1796 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1798 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1800 if(board[rt][ft] == EmptySquare) return; // no capture
1801 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1802 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1804 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1805 for(i=0; i<chaseStackPointer; i++) {
1806 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1807 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1808 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1809 chaseStack[i] = chaseStack[--chaseStackPointer];
1815 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1816 int rf, int ff, int rt, int ft,
1819 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1825 { // for determining if a piece (given through the closure) is protected
1826 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1828 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1829 if(appData.debugMode && board[rt][ft] != EmptySquare)
1830 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1833 extern char moveList[MAX_MOVES][MOVE_LEN];
1835 int PerpetualChase(int first, int last)
1836 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1839 ChessSquare captured;
1841 preyStackPointer = 0; // clear stack of chased pieces
1842 for(i=first; i<last; i+=2) { // for all positions with same side to move
1843 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1844 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1845 // determine all captures possible after the move, and put them on chaseStack
1846 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1847 if(appData.debugMode) { int n;
1848 for(n=0; n<chaseStackPointer; n++)
1849 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1850 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1851 fprintf(debugFP, ": all capts\n");
1853 // determine all captures possible before the move, and delete them from chaseStack
1854 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1855 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1856 cl.rt = moveList[i][3]-ONE;
1857 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1858 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
1859 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1860 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
1861 if(appData.debugMode) { int n;
1862 for(n=0; n<chaseStackPointer; n++)
1863 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1864 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1865 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1867 // chaseSack now contains all captures made possible by the move
1868 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1869 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1870 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1872 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1873 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1875 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1876 continue; // C or H attack on R is always chase; leave on chaseStack
1878 if(attacker == victim) {
1879 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1880 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1881 // we can capture back with equal piece, so this is no chase but a sacrifice
1882 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1883 j--; /* ! */ continue;
1888 // the attack is on a lower piece, or on a pinned or blocked equal one
1889 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
1890 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
1891 // test if the victim is protected by a true protector. First make the capture.
1892 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1893 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1894 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1895 // Then test if the opponent can recapture
1896 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1897 cl.rt = chaseStack[j].rt;
1898 cl.ft = chaseStack[j].ft;
1899 if(appData.debugMode) {
1900 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1902 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
1903 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1904 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
1905 // unmake the capture
1906 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1907 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1908 // if a recapture was found, piece is protected, and we are not chasing it.
1909 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1910 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1914 // chaseStack now contains all moves that chased
1915 if(appData.debugMode) { int n;
1916 for(n=0; n<chaseStackPointer; n++)
1917 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1918 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1919 fprintf(debugFP, ": chases\n");
1921 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1922 for(j=0; j<chaseStackPointer; j++) {
1923 preyStack[j].rank = chaseStack[j].rt;
1924 preyStack[j].file = chaseStack[j].ft;
1926 preyStackPointer = chaseStackPointer;
1929 for(j=0; j<chaseStackPointer; j++) {
1930 for(k=0; k<preyStackPointer; k++) {
1931 // search the victim of each chase move on the preyStack (first occurrence)
1932 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1933 if(k < tail) break; // piece was already identified as still being chased
1934 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1935 preyStack[tail] = preyStack[k]; // by swapping
1936 preyStack[k] = preyStack[preyStackPointer];
1942 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1943 if(appData.debugMode) { int n;
1944 for(n=0; n<preyStackPointer; n++)
1945 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1946 fprintf(debugFP, "always chased upto ply %d\n", i);
1948 // now adjust the location of the chased pieces according to opponent move
1949 for(j=0; j<preyStackPointer; j++) {
1950 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1951 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1952 preyStack[j].rank = moveList[i+1][3]-ONE;
1953 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1958 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
1959 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the