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);
739 if(promo) board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
740 check = CheckTest(board, flags, rf, ff, rt, ft,
741 kind == WhiteCapturesEnPassant ||
742 kind == BlackCapturesEnPassant);
743 if(promo) board[rf][ff] = BlackLance;
746 if (flags & F_ATOMIC_CAPTURE) {
747 if (board[rt][ft] != EmptySquare ||
748 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
750 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
751 if (board[rf][ff] == king) return;
752 for (r = rt-1; r <= rt+1; r++) {
753 for (f = ft-1; f <= ft+1; f++) {
754 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
755 board[r][f] == king) return;
760 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
767 int captures; // [HGM] losers
768 } LegalityTestClosure;
771 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
772 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
773 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
774 moves that would destroy your own king. The CASTLE_OK flags are
775 true if castling is not yet ruled out by a move of the king or
776 rook. Return TRUE if the player on move is currently in check and
777 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
778 int GenLegal(board, flags, callback, closure, filter)
781 MoveCallback callback;
786 int ff, ft, k, left, right, swap;
787 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
788 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
789 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
793 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
794 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
795 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
797 if (inCheck) return TRUE;
799 /* Generate castling moves */
800 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
801 wKing = WhiteUnicorn; bKing = BlackUnicorn;
804 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
805 if ((flags & F_WHITE_ON_MOVE) &&
806 (flags & F_WHITE_KCASTLE_OK) &&
807 board[0][ff] == wKing &&
808 board[0][ff + 1] == EmptySquare &&
809 board[0][ff + 2] == EmptySquare &&
810 board[0][BOARD_RGHT-3] == EmptySquare &&
811 board[0][BOARD_RGHT-2] == EmptySquare &&
812 board[0][BOARD_RGHT-1] == WhiteRook &&
813 castlingRights[0] != NoRights && /* [HGM] check rights */
814 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
816 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
817 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
818 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
819 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
821 callback(board, flags,
822 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
823 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
825 if ((flags & F_WHITE_ON_MOVE) &&
826 (flags & F_WHITE_QCASTLE_OK) &&
827 board[0][ff] == wKing &&
828 board[0][ff - 1] == EmptySquare &&
829 board[0][ff - 2] == EmptySquare &&
830 board[0][BOARD_LEFT+2] == EmptySquare &&
831 board[0][BOARD_LEFT+1] == EmptySquare &&
832 board[0][BOARD_LEFT+0] == WhiteRook &&
833 castlingRights[1] != NoRights && /* [HGM] check rights */
834 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
836 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
837 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
838 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
840 callback(board, flags,
841 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
842 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
844 if (!(flags & F_WHITE_ON_MOVE) &&
845 (flags & F_BLACK_KCASTLE_OK) &&
846 board[BOARD_HEIGHT-1][ff] == bKing &&
847 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
848 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
849 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
850 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
851 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
852 castlingRights[3] != NoRights && /* [HGM] check rights */
853 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
855 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
856 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
857 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
858 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
860 callback(board, flags,
861 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
862 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
864 if (!(flags & F_WHITE_ON_MOVE) &&
865 (flags & F_BLACK_QCASTLE_OK) &&
866 board[BOARD_HEIGHT-1][ff] == bKing &&
867 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
868 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
869 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
870 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
871 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
872 castlingRights[4] != NoRights && /* [HGM] check rights */
873 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
875 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
876 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
877 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
879 callback(board, flags,
880 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
881 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
885 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
887 /* generate all potential FRC castling moves (KxR), ignoring flags */
888 /* [HGM] test if the Rooks we find have castling rights */
889 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
892 if ((flags & F_WHITE_ON_MOVE) != 0) {
893 ff = castlingRights[2]; /* King file if we have any rights */
894 if(ff != NoRights && board[0][ff] == WhiteKing) {
895 if (appData.debugMode) {
896 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
897 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
899 ft = castlingRights[0]; /* Rook file if we have H-side rights */
901 right = BOARD_RGHT-2;
902 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
903 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
904 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
905 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
906 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
907 if(ft != NoRights && board[0][ft] == WhiteRook)
908 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
910 ft = castlingRights[1]; /* Rook file if we have A-side rights */
913 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
914 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
915 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
916 if(ff > BOARD_LEFT+2)
917 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
918 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
919 if(ft != NoRights && board[0][ft] == WhiteRook)
920 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
923 ff = castlingRights[5]; /* King file if we have any rights */
924 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
925 ft = castlingRights[3]; /* Rook file if we have H-side rights */
927 right = BOARD_RGHT-2;
928 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
929 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
930 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
931 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
932 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
933 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
934 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
936 ft = castlingRights[4]; /* Rook file if we have A-side rights */
939 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
940 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
941 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
942 if(ff > BOARD_LEFT+2)
943 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
944 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
945 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
946 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
962 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
963 int rf, int ff, int rt, int ft,
967 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
974 register CheckTestClosure *cl = (CheckTestClosure *) closure;
976 if (rt == cl->rking && ft == cl->fking) {
977 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
979 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
984 /* If the player on move were to move from (rf, ff) to (rt, ft), would
985 he leave himself in check? Or if rf == -1, is the player on move
986 in check now? enPassant must be TRUE if the indicated move is an
987 e.p. capture. The possibility of castling out of a check along the
988 back rank is not accounted for (i.e., we still return nonzero), as
989 this is illegal anyway. Return value is the number of times the
991 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
994 int rf, ff, rt, ft, enPassant;
997 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
998 ChessSquare captured = EmptySquare;
999 /* Suppress warnings on uninitialized variables */
1001 if(gameInfo.variant == VariantXiangqi)
1002 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1003 if(gameInfo.variant == VariantKnightmate)
1004 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1008 captured = board[rf][ft];
1009 board[rf][ft] = EmptySquare;
1011 captured = board[rt][ft];
1013 board[rt][ft] = board[rf][ff];
1014 board[rf][ff] = EmptySquare;
1015 } else board[rt][ft] = ff; // [HGM] drop
1017 /* For compatibility with ICS wild 9, we scan the board in the
1018 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1019 and we test only whether that one is in check. */
1020 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1021 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1022 if (board[cl.rking][cl.fking] == king) {
1024 if(gameInfo.variant == VariantXiangqi) {
1025 /* [HGM] In Xiangqi opposing Kings means check as well */
1027 dir = (king >= BlackPawn) ? -1 : 1;
1028 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1029 board[i][cl.fking] == EmptySquare; i+=dir );
1030 if(i>=0 && i<BOARD_HEIGHT &&
1031 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1034 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1035 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1036 goto undo_move; /* 2-level break */
1043 board[rf][ff] = board[rt][ft];
1045 board[rf][ft] = captured;
1046 board[rt][ft] = EmptySquare;
1048 board[rt][ft] = captured;
1050 } else board[rt][ft] = EmptySquare; // [HGM] drop
1052 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1055 ChessMove LegalDrop(board, flags, piece, rt, ft)
1060 { // [HGM] put drop legality testing in separate routine for clarity
1062 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1063 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1064 n = PieceToNumber(piece);
1065 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1066 return ImpossibleMove; // piece not available
1067 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1068 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1069 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1070 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1071 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1072 if(piece == WhitePawn || piece == BlackPawn) {
1074 for(r=1; r<BOARD_HEIGHT-1; r++)
1075 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1076 // should still test if we mate with this Pawn
1078 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1079 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1081 if( (piece == WhitePawn || piece == BlackPawn) &&
1082 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1083 return IllegalMove; /* no pawn drops on 1st/8th */
1085 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1086 if (!(flags & F_IGNORE_CHECK) &&
1087 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1088 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1091 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1092 int rf, int ff, int rt, int ft,
1095 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1102 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1104 // if (appData.debugMode) {
1105 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1107 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1108 cl->captures++; // [HGM] losers: count legal captures
1109 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1113 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1116 int rf, ff, rt, ft, promoChar;
1118 LegalityTestClosure cl; ChessSquare piece, filterPiece, *castlingRights = board[CASTLING];
1120 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1121 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1122 piece = filterPiece = board[rf][ff];
1123 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1125 if (appData.debugMode) {
1127 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1128 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1130 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1131 /* (perhaps we should disallow moves that obviously leave us in check?) */
1132 if(piece == WhiteFalcon || piece == BlackFalcon ||
1133 piece == WhiteCobra || piece == BlackCobra)
1134 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1138 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1139 cl.ft = fFilter = ft;
1140 cl.kind = IllegalMove;
1141 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1142 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1143 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1144 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1145 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1146 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1148 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1149 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1150 if(board[rf][ff] < BlackPawn) { // white
1151 if(rf != 0) return IllegalMove; // must be on back rank
1152 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1154 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1155 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1158 if(gameInfo.variant == VariantShogi) {
1159 /* [HGM] Shogi promotions. '=' means defer */
1160 if(rf != DROP_RANK && cl.kind == NormalMove) {
1161 ChessSquare piece = board[rf][ff];
1163 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1164 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1165 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1166 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1167 promoChar = '+'; // allowed ICS notations
1168 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1169 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1170 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1171 else if(flags & F_WHITE_ON_MOVE) {
1172 if( (int) piece < (int) WhiteWazir &&
1173 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1174 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1175 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1176 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1177 else /* promotion optional, default is defer */
1178 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1179 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1181 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1182 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1183 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1184 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1185 else /* promotion optional, default is defer */
1186 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1187 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1191 if (promoChar != NULLCHAR) {
1192 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1193 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1194 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1195 if(piece == EmptySquare)
1196 cl.kind = ImpossibleMove; // non-existing piece
1197 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1198 if(promoChar != PieceToChar(BlackKing)) {
1199 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1200 if(piece == BlackLance) cl.kind = ImpossibleMove;
1201 } else { // promotion to King allowed only if we do not haave two yet
1202 int r, f, kings = 0;
1203 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1204 if(kings == 2) cl.kind = IllegalMove;
1206 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1207 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1208 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1209 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1210 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1211 cl.kind = IllegalMove; // promotion to King usually not allowed
1213 cl.kind = IllegalMove;
1223 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1224 int rf, int ff, int rt, int ft,
1227 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1234 register MateTestClosure *cl = (MateTestClosure *) closure;
1239 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1240 int MateTest(board, flags)
1245 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1246 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1248 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1249 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1250 nrKing += (board[r][f] == king); // stm has king
1251 if( board[r][f] != EmptySquare ) {
1252 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1257 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1258 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1259 case VariantShatranj:
1260 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1264 if(nrKing == 0) return MT_NOKING;
1267 if(myPieces == 1) return MT_BARE;
1270 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1271 // [HGM] 3check: yet to do!
1273 return inCheck ? MT_CHECK : MT_NONE;
1275 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1276 && gameInfo.variant != VariantGrand) { // drop game
1277 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1278 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1279 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1280 if(board[n][holdings] != EmptySquare) {
1281 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1282 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1285 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1286 return myPieces == hisPieces ? MT_STALEMATE :
1287 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1288 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1289 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1291 return inCheck ? MT_CHECKMATE
1292 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1293 MT_STAINMATE : MT_STALEMATE;
1298 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1299 int rf, int ff, int rt, int ft,
1302 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1309 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1310 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1312 // [HGM] wild: for wild-card pieces rt and rf are dummies
1313 if(piece == WhiteFalcon || piece == BlackFalcon ||
1314 piece == WhiteCobra || piece == BlackCobra)
1317 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1318 || PieceToChar(board[rf][ff]) == '~'
1319 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1321 (cl->rfIn == -1 || cl->rfIn == rf) &&
1322 (cl->ffIn == -1 || cl->ffIn == ff) &&
1323 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1324 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1327 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1328 // [HGM] oneclick: if multiple moves, be sure we remember capture
1329 cl->piece = board[rf][ff];
1332 cl->rt = wildCard ? cl->rtIn : rt;
1333 cl->ft = wildCard ? cl->ftIn : ft;
1336 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1340 void Disambiguate(board, flags, closure)
1343 DisambiguateClosure *closure;
1345 int illegal = 0; char c = closure->promoCharIn;
1347 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1348 closure->count = closure->captures = 0;
1349 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1350 closure->kind = ImpossibleMove;
1351 if (appData.debugMode) {
1352 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1353 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1354 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1356 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1357 fFilter = closure->ftIn;
1358 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1359 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1360 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1361 closure->count = closure->captures = 0;
1362 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1363 closure->kind = ImpossibleMove;
1364 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1367 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1368 if (closure->count == 0) {
1369 /* See if it's an illegal move due to check */
1371 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1372 if (closure->count == 0) {
1373 /* No, it's not even that */
1374 if (appData.debugMode) { int i, j;
1375 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1376 for(j=0; j<BOARD_WIDTH; j++)
1377 fprintf(debugFP, "%3d", (int) board[i][j]);
1378 fprintf(debugFP, "\n");
1385 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1386 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1387 if(closure->piece < BlackPawn) { // white
1388 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1389 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1391 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1392 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1395 if(gameInfo.variant == VariantShogi) {
1396 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1397 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1398 ChessSquare piece = closure->piece;
1399 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1400 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1401 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1402 c = '+'; // allowed ICS notations
1403 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1404 else if(flags & F_WHITE_ON_MOVE) {
1405 if( (int) piece < (int) WhiteWazir &&
1406 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1407 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1408 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1409 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1410 else /* promotion optional, default is defer */
1411 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1412 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1414 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1415 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1416 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1417 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1418 else /* promotion optional, default is defer */
1419 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1420 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1423 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1424 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1426 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1427 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1428 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier || gameInfo.variant == VariantMakruk)
1429 c = PieceToChar(BlackFerz);
1430 else if(gameInfo.variant == VariantGreat)
1431 c = PieceToChar(BlackMan);
1432 else if(gameInfo.variant == VariantGrand)
1433 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1435 c = PieceToChar(BlackQueen);
1436 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1437 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1439 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1440 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1441 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1442 if (closure->count > 1) {
1443 closure->kind = AmbiguousMove;
1446 /* Note: If more than one illegal move matches, but no legal
1447 moves, we return IllegalMove, not AmbiguousMove. Caller
1448 can look at closure->count to detect this.
1450 closure->kind = IllegalMove;
1452 if (appData.debugMode) {
1453 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1454 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1455 closure->promoChar >= ' ' ? closure->promoChar:'-');
1469 } CoordsToAlgebraicClosure;
1471 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1472 ChessMove kind, int rf, int ff,
1473 int rt, int ft, VOIDSTAR closure));
1475 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1482 register CoordsToAlgebraicClosure *cl =
1483 (CoordsToAlgebraicClosure *) closure;
1485 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1486 (board[rf][ff] == cl->piece
1487 || PieceToChar(board[rf][ff]) == '~' &&
1488 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1492 cl->kind = kind; /* this is the move we want */
1494 cl->file++; /* need file to rule out this move */
1498 cl->rank++; /* need rank to rule out this move */
1500 cl->either++; /* rank or file will rule out this move */
1506 /* Convert coordinates to normal algebraic notation.
1507 promoChar must be NULLCHAR or 'x' if not a promotion.
1509 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1518 char *outp = out, c;
1519 CoordsToAlgebraicClosure cl;
1521 if (rf == DROP_RANK) {
1522 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
1523 /* Bughouse piece drop */
1524 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1529 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1531 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1534 if (promoChar == 'x') promoChar = NULLCHAR;
1535 piece = board[rf][ff];
1536 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1538 if (appData.debugMode)
1539 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1543 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1544 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1545 /* Keep short notation if move is illegal only because it
1546 leaves the player in check, but still return IllegalMove */
1547 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1548 if (kind == IllegalMove) break;
1553 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1554 /* Non-capture; use style "e5" */
1557 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1559 /* Capture; use style "exd5" */
1560 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1561 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1565 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1567 /* Use promotion suffix style "=Q" */
1569 if (appData.debugMode)
1570 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1571 if (promoChar != NULLCHAR) {
1572 if(gameInfo.variant == VariantShogi) {
1573 /* [HGM] ... but not in Shogi! */
1574 *outp++ = promoChar == '=' ? '=' : '+';
1577 *outp++ = ToUpper(promoChar);
1586 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1587 /* Code added by Tord: FRC castling. */
1588 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1589 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1591 safeStrCpy(out, "O-O", MOVE_LEN);
1593 safeStrCpy(out, "O-O-O", MOVE_LEN);
1594 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1596 /* End of code added by Tord */
1597 /* Test for castling or ICS wild castling */
1598 /* Use style "O-O" (oh-oh) for PGN compatibility */
1599 else if (rf == rt &&
1600 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1601 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1602 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1603 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1604 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1605 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1607 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1609 /* This notation is always unambiguous, unless there are
1610 kings on both the d and e files, with "wild castling"
1611 possible for the king on the d file and normal castling
1612 possible for the other. ICS rules for wild 9
1613 effectively make castling illegal for either king in
1614 this situation. So I am not going to worry about it;
1615 I'll just generate an ambiguous O-O in this case.
1617 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1620 /* else fall through */
1625 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1626 cl.ft = fFilter = ft;
1628 cl.kind = IllegalMove;
1629 cl.rank = cl.file = cl.either = 0;
1630 c = PieceToChar(piece) ;
1631 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1633 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1634 /* Generate pretty moves for moving into check, but
1635 still return IllegalMove.
1637 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1638 if (cl.kind == IllegalMove) break;
1639 cl.kind = IllegalMove;
1642 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1643 else "Ngf3" or "Ngxf7",
1644 else "N1f3" or "N5xf7",
1645 else "Ng1f3" or "Ng5xf7".
1647 if( c == '~' || c == '+') {
1648 /* [HGM] print nonexistent piece as its demoted version */
1649 piece = (ChessSquare) (DEMOTED piece);
1651 if(c=='+') *outp++ = c;
1652 *outp++ = ToUpper(PieceToChar(piece));
1654 if (cl.file || (cl.either && !cl.rank)) {
1660 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1663 if(board[rt][ft] != EmptySquare)
1669 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1670 if (gameInfo.variant == VariantShogi) {
1671 /* [HGM] in Shogi non-pawns can promote */
1672 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1674 else if (gameInfo.variant != VariantSuper && promoChar &&
1675 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1677 *outp++ = ToUpper(promoChar);
1679 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1681 *outp++ = ToUpper(promoChar);
1687 /* Moving a nonexistent piece */
1691 /* Not a legal move, even ignoring check.
1692 If there was a piece on the from square,
1693 use style "Ng1g3" or "Ng1xe8";
1694 if there was a pawn or nothing (!),
1695 use style "g1g3" or "g1xe8". Use "x"
1696 if a piece was on the to square, even
1697 a piece of the same color.
1701 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1703 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1704 c += (board[r][f] == piece); // count on-board pieces of given type
1705 *outp++ = ToUpper(PieceToChar(piece));
1707 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1711 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1713 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1717 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1718 /* Use promotion suffix style "=Q" */
1719 if (promoChar != NULLCHAR && promoChar != 'x') {
1721 *outp++ = ToUpper(promoChar);
1728 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1737 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1739 int preyStackPointer, chaseStackPointer;
1742 unsigned char rf, ff, rt, ft;
1746 unsigned char rank, file;
1752 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1754 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1755 int rf, int ff, int rt, int ft,
1758 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1764 { // For adding captures that can lead to chase indictment to the chaseStack
1765 if(board[rt][ft] == EmptySquare) return; // non-capture
1766 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1767 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1768 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1769 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1770 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1771 chaseStack[chaseStackPointer].rf = rf;
1772 chaseStack[chaseStackPointer].ff = ff;
1773 chaseStack[chaseStackPointer].rt = rt;
1774 chaseStack[chaseStackPointer].ft = ft;
1775 chaseStackPointer++;
1778 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1779 int rf, int ff, int rt, int ft,
1782 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1788 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1790 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1792 if(board[rt][ft] == EmptySquare) return; // no capture
1793 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1794 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1796 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1797 for(i=0; i<chaseStackPointer; i++) {
1798 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1799 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1800 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1801 chaseStack[i] = chaseStack[--chaseStackPointer];
1807 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1808 int rf, int ff, int rt, int ft,
1811 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1817 { // for determining if a piece (given through the closure) is protected
1818 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1820 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1821 if(appData.debugMode && board[rt][ft] != EmptySquare)
1822 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1825 extern char moveList[MAX_MOVES][MOVE_LEN];
1827 int PerpetualChase(int first, int last)
1828 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1831 ChessSquare captured;
1833 preyStackPointer = 0; // clear stack of chased pieces
1834 for(i=first; i<last; i+=2) { // for all positions with same side to move
1835 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1836 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1837 // determine all captures possible after the move, and put them on chaseStack
1838 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1839 if(appData.debugMode) { int n;
1840 for(n=0; n<chaseStackPointer; n++)
1841 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1842 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1843 fprintf(debugFP, ": all capts\n");
1845 // determine all captures possible before the move, and delete them from chaseStack
1846 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1847 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1848 cl.rt = moveList[i][3]-ONE;
1849 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1850 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
1851 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1852 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
1853 if(appData.debugMode) { int n;
1854 for(n=0; n<chaseStackPointer; n++)
1855 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1856 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1857 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1859 // chaseSack now contains all captures made possible by the move
1860 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1861 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1862 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1864 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1865 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1867 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1868 continue; // C or H attack on R is always chase; leave on chaseStack
1870 if(attacker == victim) {
1871 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1872 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1873 // we can capture back with equal piece, so this is no chase but a sacrifice
1874 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1875 j--; /* ! */ continue;
1880 // the attack is on a lower piece, or on a pinned or blocked equal one
1881 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
1882 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
1883 // test if the victim is protected by a true protector. First make the capture.
1884 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1885 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1886 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1887 // Then test if the opponent can recapture
1888 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1889 cl.rt = chaseStack[j].rt;
1890 cl.ft = chaseStack[j].ft;
1891 if(appData.debugMode) {
1892 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1894 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
1895 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1896 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
1897 // unmake the capture
1898 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1899 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1900 // if a recapture was found, piece is protected, and we are not chasing it.
1901 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1902 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1906 // chaseStack now contains all moves that chased
1907 if(appData.debugMode) { int n;
1908 for(n=0; n<chaseStackPointer; n++)
1909 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1910 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1911 fprintf(debugFP, ": chases\n");
1913 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1914 for(j=0; j<chaseStackPointer; j++) {
1915 preyStack[j].rank = chaseStack[j].rt;
1916 preyStack[j].file = chaseStack[j].ft;
1918 preyStackPointer = chaseStackPointer;
1921 for(j=0; j<chaseStackPointer; j++) {
1922 for(k=0; k<preyStackPointer; k++) {
1923 // search the victim of each chase move on the preyStack (first occurrence)
1924 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1925 if(k < tail) break; // piece was already identified as still being chased
1926 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1927 preyStack[tail] = preyStack[k]; // by swapping
1928 preyStack[k] = preyStack[preyStackPointer];
1934 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1935 if(appData.debugMode) { int n;
1936 for(n=0; n<preyStackPointer; n++)
1937 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1938 fprintf(debugFP, "always chased upto ply %d\n", i);
1940 // now adjust the location of the chased pieces according to opponent move
1941 for(j=0; j<preyStackPointer; j++) {
1942 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1943 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1944 preyStack[j].rank = moveList[i+1][3]-ONE;
1945 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1950 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
1951 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the