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, 2012 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 */
76 WhitePiece (ChessSquare piece)
78 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
82 BlackPiece (ChessSquare piece)
84 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
89 SameColor (ChessSquare piece1, ChessSquare 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];
113 PieceToChar (ChessSquare p)
115 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
116 return pieceToChar[(int) p];
120 PieceToNumber (ChessSquare 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++;
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;
142 CopyBoard (Board to, Board 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
155 CompareBoards (Board board1, Board 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.
177 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
178 // speed: only do moves with this piece type
181 int i, j, d, s, fs, rs, rt, ft, m;
182 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
183 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand ? 3 : 1;
185 for (rf = 0; rf < BOARD_HEIGHT; rf++)
186 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
190 if(board[rf][ff] == EmptySquare) continue;
191 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
193 m = 0; piece = board[rf][ff];
194 if(PieceToChar(piece) == '~')
195 piece = (ChessSquare) ( DEMOTED piece );
196 if(filter != EmptySquare && piece != filter) continue;
197 if(gameInfo.variant == VariantShogi)
198 piece = (ChessSquare) ( SHOGI piece );
200 switch ((int)piece) {
201 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
203 /* can't happen ([HGM] except for faries...) */
207 if(gameInfo.variant == VariantXiangqi) {
208 /* [HGM] capture and move straight ahead in Xiangqi */
209 if (rf < BOARD_HEIGHT-1 &&
210 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
211 callback(board, flags, NormalMove,
212 rf, ff, rf + 1, ff, closure);
214 /* and move sideways when across the river */
215 for (s = -1; s <= 1; s += 2) {
216 if (rf >= BOARD_HEIGHT>>1 &&
217 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
218 !WhitePiece(board[rf][ff+s]) ) {
219 callback(board, flags, NormalMove,
220 rf, ff, rf, ff+s, closure);
225 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
226 callback(board, flags,
227 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
228 rf, ff, rf + 1, ff, closure);
230 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
231 gameInfo.variant != VariantShatranj && /* [HGM] */
232 gameInfo.variant != VariantCourier && /* [HGM] */
233 board[rf+2][ff] == EmptySquare ) {
234 callback(board, flags, NormalMove,
235 rf, ff, rf+2, ff, closure);
237 for (s = -1; s <= 1; s += 2) {
238 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
239 ((flags & F_KRIEGSPIEL_CAPTURE) ||
240 BlackPiece(board[rf + 1][ff + s]))) {
241 callback(board, flags,
242 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
243 rf, ff, rf + 1, ff + s, closure);
245 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
246 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
247 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
248 board[rf][ff + s] == BlackPawn &&
249 board[rf+1][ff + s] == EmptySquare) {
250 callback(board, flags, WhiteCapturesEnPassant,
251 rf, ff, rf+1, ff + s, closure);
258 if(gameInfo.variant == VariantXiangqi) {
259 /* [HGM] capture straight ahead in Xiangqi */
260 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
261 callback(board, flags, NormalMove,
262 rf, ff, rf - 1, ff, closure);
264 /* and move sideways when across the river */
265 for (s = -1; s <= 1; s += 2) {
266 if (rf < BOARD_HEIGHT>>1 &&
267 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
268 !BlackPiece(board[rf][ff+s]) ) {
269 callback(board, flags, NormalMove,
270 rf, ff, rf, ff+s, closure);
275 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
276 callback(board, flags,
277 rf <= promoRank ? BlackPromotion : NormalMove,
278 rf, ff, rf - 1, ff, closure);
280 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
281 gameInfo.variant != VariantShatranj && /* [HGM] */
282 gameInfo.variant != VariantCourier && /* [HGM] */
283 board[rf-2][ff] == EmptySquare) {
284 callback(board, flags, NormalMove,
285 rf, ff, rf-2, ff, closure);
287 for (s = -1; s <= 1; s += 2) {
288 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
289 ((flags & F_KRIEGSPIEL_CAPTURE) ||
290 WhitePiece(board[rf - 1][ff + s]))) {
291 callback(board, flags,
292 rf <= promoRank ? BlackPromotion : NormalMove,
293 rf, ff, rf - 1, ff + s, closure);
295 if (rf < BOARD_HEIGHT>>1) {
296 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
297 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
298 board[rf][ff + s] == WhitePawn &&
299 board[rf-1][ff + s] == EmptySquare) {
300 callback(board, flags, BlackCapturesEnPassant,
301 rf, ff, rf-1, ff + s, closure);
312 for (i = -1; i <= 1; i += 2)
313 for (j = -1; j <= 1; j += 2)
314 for (s = 1; s <= 2; s++) {
317 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
318 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
319 && !SameColor(board[rf][ff], board[rt][ft]))
320 callback(board, flags, NormalMove,
321 rf, ff, rt, ft, closure);
325 case SHOGI WhiteKnight:
326 for (s = -1; s <= 1; s += 2) {
327 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
328 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
329 callback(board, flags, NormalMove,
330 rf, ff, rf + 2, ff + s, closure);
335 case SHOGI BlackKnight:
336 for (s = -1; s <= 1; s += 2) {
337 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
338 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
339 callback(board, flags, NormalMove,
340 rf, ff, rf - 2, ff + s, closure);
347 for (d = 0; d <= 1; d++)
348 for (s = -1; s <= 1; s += 2) {
351 rt = rf + (i * s) * d;
352 ft = ff + (i * s) * (1 - d);
353 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
354 if (m == 0 && board[rt][ft] == EmptySquare)
355 callback(board, flags, NormalMove,
356 rf, ff, rt, ft, closure);
357 if (m == 1 && board[rt][ft] != EmptySquare &&
358 !SameColor(board[rf][ff], board[rt][ft]) )
359 callback(board, flags, NormalMove,
360 rf, ff, rt, ft, closure);
361 if (board[rt][ft] != EmptySquare && m++) break;
366 /* Gold General (and all its promoted versions) . First do the */
367 /* diagonal forward steps, then proceed as normal Wazir */
368 case SHOGI WhiteWazir:
369 case SHOGI (PROMOTED WhitePawn):
370 case SHOGI (PROMOTED WhiteKnight):
371 case SHOGI (PROMOTED WhiteQueen):
372 case SHOGI (PROMOTED WhiteFerz):
373 for (s = -1; s <= 1; s += 2) {
374 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
375 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
376 callback(board, flags, NormalMove,
377 rf, ff, rf + 1, ff + s, closure);
382 case SHOGI BlackWazir:
383 case SHOGI (PROMOTED BlackPawn):
384 case SHOGI (PROMOTED BlackKnight):
385 case SHOGI (PROMOTED BlackQueen):
386 case SHOGI (PROMOTED BlackFerz):
387 for (s = -1; s <= 1; s += 2) {
388 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
389 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
390 callback(board, flags, NormalMove,
391 rf, ff, rf - 1, ff + s, closure);
398 for (d = 0; d <= 1; d++)
399 for (s = -1; s <= 1; s += 2) {
401 ft = ff + s * (1 - d);
402 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
403 && !SameColor(board[rf][ff], board[rt][ft]) &&
404 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
405 callback(board, flags, NormalMove,
406 rf, ff, rt, ft, closure);
412 /* [HGM] support Shatranj pieces */
413 for (rs = -1; rs <= 1; rs += 2)
414 for (fs = -1; fs <= 1; fs += 2) {
417 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
418 && ( gameInfo.variant != VariantXiangqi ||
419 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
421 && !SameColor(board[rf][ff], board[rt][ft]))
422 callback(board, flags, NormalMove,
423 rf, ff, rt, ft, closure);
424 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier
425 || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
426 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
428 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
429 && !SameColor(board[rf][ff], board[rt][ft]))
430 callback(board, flags, NormalMove,
431 rf, ff, rt, ft, closure);
433 if(gameInfo.variant == VariantSpartan)
434 for(fs = -1; fs <= 1; fs += 2) {
436 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
437 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
441 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
444 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
445 for (s = -2; s <= 2; s += 4) {
447 ft = ff + s * (1 - d);
448 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
449 if (SameColor(board[rf][ff], board[rt][ft])) continue;
450 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
453 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
454 case SHOGI WhiteCardinal:
455 case SHOGI BlackCardinal:
458 /* Capablanca Archbishop continues as Knight */
463 /* Shogi Bishops are ordinary Bishops */
464 case SHOGI WhiteBishop:
465 case SHOGI BlackBishop:
468 for (rs = -1; rs <= 1; rs += 2)
469 for (fs = -1; fs <= 1; fs += 2)
473 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
474 if (SameColor(board[rf][ff], board[rt][ft])) break;
475 callback(board, flags, NormalMove,
476 rf, ff, rt, ft, closure);
477 if (board[rt][ft] != EmptySquare) break;
479 if(m==1) goto mounted;
480 if(m==2) goto finishGold;
481 /* Bishop falls through */
484 /* Shogi Lance is unlike anything, and asymmetric at that */
485 case SHOGI WhiteQueen:
489 if (rt >= BOARD_HEIGHT) break;
490 if (SameColor(board[rf][ff], board[rt][ft])) break;
491 callback(board, flags, NormalMove,
492 rf, ff, rt, ft, closure);
493 if (board[rt][ft] != EmptySquare) break;
497 case SHOGI BlackQueen:
502 if (SameColor(board[rf][ff], board[rt][ft])) break;
503 callback(board, flags, NormalMove,
504 rf, ff, rt, ft, closure);
505 if (board[rt][ft] != EmptySquare) break;
509 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
512 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
513 for (s = -2; s <= 2; s += 4) {
515 ft = ff + s * (1 - d);
516 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT || board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
517 if (SameColor(board[rf][ff], board[rt][ft])) continue;
518 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
520 if(gameInfo.variant == VariantSpartan) rookRange = 2; // in Spartan Chess restrict range to modern Dababba
523 /* Shogi Dragon King has to continue as Ferz after Rook moves */
524 case SHOGI WhiteDragon:
525 case SHOGI BlackDragon:
528 /* Capablanca Chancellor sets flag to continue as Knight */
532 m += (gameInfo.variant == VariantSpartan); // in Spartan Chess Chancellor is used for Dragon King.
534 /* Shogi Rooks are ordinary Rooks */
535 case SHOGI WhiteRook:
536 case SHOGI BlackRook:
540 for (d = 0; d <= 1; d++)
541 for (s = -1; s <= 1; s += 2)
543 rt = rf + (i * s) * d;
544 ft = ff + (i * s) * (1 - d);
545 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
546 if (SameColor(board[rf][ff], board[rt][ft])) break;
547 callback(board, flags, NormalMove,
548 rf, ff, rt, ft, closure);
549 if (board[rt][ft] != EmptySquare || i == rookRange) break;
551 if(m==1) goto mounted;
552 if(m==2) goto finishSilver;
557 for (rs = -1; rs <= 1; rs++)
558 for (fs = -1; fs <= 1; fs++) {
559 if (rs == 0 && fs == 0) continue;
563 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
564 if (SameColor(board[rf][ff], board[rt][ft])) break;
565 callback(board, flags, NormalMove,
566 rf, ff, rt, ft, closure);
567 if (board[rt][ft] != EmptySquare) break;
572 /* Shogi Pawn and Silver General: first the Pawn move, */
573 /* then the General continues like a Ferz */
575 if(gameInfo.variant != VariantMakruk) goto commoner;
576 case SHOGI WhitePawn:
577 case SHOGI WhiteFerz:
578 if (rf < BOARD_HEIGHT-1 &&
579 !SameColor(board[rf][ff], board[rf + 1][ff]) )
580 callback(board, flags, NormalMove,
581 rf, ff, rf + 1, ff, closure);
582 if(piece != SHOGI WhitePawn) goto finishSilver;
586 if(gameInfo.variant != VariantMakruk) goto commoner;
587 case SHOGI BlackPawn:
588 case SHOGI BlackFerz:
590 !SameColor(board[rf][ff], board[rf - 1][ff]) )
591 callback(board, flags, NormalMove,
592 rf, ff, rf - 1, ff, closure);
593 if(piece == SHOGI BlackPawn) break;
598 /* [HGM] support Shatranj pieces */
599 for (rs = -1; rs <= 1; rs += 2)
600 for (fs = -1; fs <= 1; fs += 2) {
603 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
604 if (!SameColor(board[rf][ff], board[rt][ft]) &&
605 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
606 callback(board, flags, NormalMove,
607 rf, ff, rt, ft, closure);
613 m++; // [HGM] superchess: use for Centaur
615 case SHOGI WhiteKing:
616 case SHOGI BlackKing:
620 for (i = -1; i <= 1; i++)
621 for (j = -1; j <= 1; j++) {
622 if (i == 0 && j == 0) continue;
625 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
626 if (SameColor(board[rf][ff], board[rt][ft])) continue;
627 callback(board, flags, NormalMove,
628 rf, ff, rt, ft, closure);
630 if(m==1) goto mounted;
633 case WhiteNightrider:
634 case BlackNightrider:
635 for (i = -1; i <= 1; i += 2)
636 for (j = -1; j <= 1; j += 2)
637 for (s = 1; s <= 2; s++) { int k;
641 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
642 if (SameColor(board[rf][ff], board[rt][ft])) break;
643 callback(board, flags, NormalMove,
644 rf, ff, rt, ft, closure);
645 if (board[rt][ft] != EmptySquare) break;
651 /* First do Bishop,then continue like Chancellor */
652 for (rs = -1; rs <= 1; rs += 2)
653 for (fs = -1; fs <= 1; fs += 2)
657 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
658 if (SameColor(board[rf][ff], board[rt][ft])) break;
659 callback(board, flags, NormalMove,
660 rf, ff, rt, ft, closure);
661 if (board[rt][ft] != EmptySquare) break;
666 // Use Lance as Berolina / Spartan Pawn.
668 if(gameInfo.variant == VariantSuper) goto Amazon;
669 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
670 callback(board, flags,
671 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
672 rf, ff, rf + 1, ff, closure);
673 for (s = -1; s <= 1; s += 2) {
674 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
675 callback(board, flags,
676 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
677 rf, ff, rf + 1, ff + s, closure);
678 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
679 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
684 if(gameInfo.variant == VariantSuper) goto Amazon;
685 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
686 callback(board, flags,
687 rf <= promoRank ? BlackPromotion : NormalMove,
688 rf, ff, rf - 1, ff, closure);
689 for (s = -1; s <= 1; s += 2) {
690 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
691 callback(board, flags,
692 rf <= promoRank ? BlackPromotion : NormalMove,
693 rf, ff, rf - 1, ff + s, closure);
694 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
695 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
699 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
703 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
716 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
717 Board xqCheckers, nullBoard;
719 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
720 int rf, int ff, int rt, int ft,
724 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
726 register GenLegalClosure *cl = (GenLegalClosure *) closure;
728 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
730 if (!(flags & F_IGNORE_CHECK) ) {
731 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
734 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
735 kings += (board[r][f] == BlackKing);
739 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
741 check = CheckTest(board, flags, rf, ff, rt, ft,
742 kind == WhiteCapturesEnPassant ||
743 kind == BlackCapturesEnPassant);
744 if(promo) board[rf][ff] = BlackLance;
747 if (flags & F_ATOMIC_CAPTURE) {
748 if (board[rt][ft] != EmptySquare ||
749 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
751 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
752 if (board[rf][ff] == king) return;
753 for (r = rt-1; r <= rt+1; r++) {
754 for (f = ft-1; f <= ft+1; f++) {
755 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
756 board[r][f] == king) return;
761 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
768 int captures; // [HGM] losers
769 } LegalityTestClosure;
772 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
773 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
774 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
775 moves that would destroy your own king. The CASTLE_OK flags are
776 true if castling is not yet ruled out by a move of the king or
777 rook. Return TRUE if the player on move is currently in check and
778 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
780 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
783 int ff, ft, k, left, right, swap;
784 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
785 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
786 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
790 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
791 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
792 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
794 if (inCheck) return TRUE;
796 /* Generate castling moves */
797 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
798 wKing = WhiteUnicorn; bKing = BlackUnicorn;
801 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
802 if ((flags & F_WHITE_ON_MOVE) &&
803 (flags & F_WHITE_KCASTLE_OK) &&
804 board[0][ff] == wKing &&
805 board[0][ff + 1] == EmptySquare &&
806 board[0][ff + 2] == EmptySquare &&
807 board[0][BOARD_RGHT-3] == EmptySquare &&
808 board[0][BOARD_RGHT-2] == EmptySquare &&
809 board[0][BOARD_RGHT-1] == WhiteRook &&
810 castlingRights[0] != NoRights && /* [HGM] check rights */
811 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
813 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
814 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
815 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
816 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
818 callback(board, flags,
819 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
820 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
822 if ((flags & F_WHITE_ON_MOVE) &&
823 (flags & F_WHITE_QCASTLE_OK) &&
824 board[0][ff] == wKing &&
825 board[0][ff - 1] == EmptySquare &&
826 board[0][ff - 2] == EmptySquare &&
827 board[0][BOARD_LEFT+2] == EmptySquare &&
828 board[0][BOARD_LEFT+1] == EmptySquare &&
829 board[0][BOARD_LEFT+0] == WhiteRook &&
830 castlingRights[1] != NoRights && /* [HGM] check rights */
831 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
833 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
834 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
835 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
837 callback(board, flags,
838 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
839 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
841 if (!(flags & F_WHITE_ON_MOVE) &&
842 (flags & F_BLACK_KCASTLE_OK) &&
843 board[BOARD_HEIGHT-1][ff] == bKing &&
844 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
845 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
846 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
847 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
848 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
849 castlingRights[3] != NoRights && /* [HGM] check rights */
850 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
852 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
853 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
854 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
855 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
857 callback(board, flags,
858 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
859 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
861 if (!(flags & F_WHITE_ON_MOVE) &&
862 (flags & F_BLACK_QCASTLE_OK) &&
863 board[BOARD_HEIGHT-1][ff] == bKing &&
864 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
865 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
866 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
867 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
868 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
869 castlingRights[4] != NoRights && /* [HGM] check rights */
870 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
872 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
873 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
874 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
876 callback(board, flags,
877 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
878 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
882 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
884 /* generate all potential FRC castling moves (KxR), ignoring flags */
885 /* [HGM] test if the Rooks we find have castling rights */
886 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
889 if ((flags & F_WHITE_ON_MOVE) != 0) {
890 ff = castlingRights[2]; /* King file if we have any rights */
891 if(ff != NoRights && board[0][ff] == WhiteKing) {
892 if (appData.debugMode) {
893 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
894 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
896 ft = castlingRights[0]; /* Rook file if we have H-side rights */
898 right = BOARD_RGHT-2;
899 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
900 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
901 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
902 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
903 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
904 if(ft != NoRights && board[0][ft] == WhiteRook)
905 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
907 ft = castlingRights[1]; /* Rook file if we have A-side rights */
910 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
911 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
912 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
913 if(ff > BOARD_LEFT+2)
914 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
915 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
916 if(ft != NoRights && board[0][ft] == WhiteRook)
917 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
920 ff = castlingRights[5]; /* King file if we have any rights */
921 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
922 ft = castlingRights[3]; /* Rook file if we have H-side rights */
924 right = BOARD_RGHT-2;
925 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
926 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
927 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
928 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
929 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
930 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
931 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
933 ft = castlingRights[4]; /* Rook file if we have A-side rights */
936 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
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 if(ff > BOARD_LEFT+2)
940 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
941 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
942 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
943 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
959 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
960 int rf, int ff, int rt, int ft,
965 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
967 register CheckTestClosure *cl = (CheckTestClosure *) closure;
969 if (rt == cl->rking && ft == cl->fking) {
970 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
972 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
977 /* If the player on move were to move from (rf, ff) to (rt, ft), would
978 he leave himself in check? Or if rf == -1, is the player on move
979 in check now? enPassant must be TRUE if the indicated move is an
980 e.p. capture. The possibility of castling out of a check along the
981 back rank is not accounted for (i.e., we still return nonzero), as
982 this is illegal anyway. Return value is the number of times the
985 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
988 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
989 ChessSquare captured = EmptySquare;
990 /* Suppress warnings on uninitialized variables */
992 if(gameInfo.variant == VariantXiangqi)
993 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
994 if(gameInfo.variant == VariantKnightmate)
995 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
999 captured = board[rf][ft];
1000 board[rf][ft] = EmptySquare;
1002 captured = board[rt][ft];
1004 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1005 board[rt][ft] = board[rf][ff];
1006 board[rf][ff] = EmptySquare;
1010 /* For compatibility with ICS wild 9, we scan the board in the
1011 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1012 and we test only whether that one is in check. */
1013 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1014 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1015 if (board[cl.rking][cl.fking] == king) {
1017 if(gameInfo.variant == VariantXiangqi) {
1018 /* [HGM] In Xiangqi opposing Kings means check as well */
1020 dir = (king >= BlackPawn) ? -1 : 1;
1021 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1022 board[i][cl.fking] == EmptySquare; i+=dir );
1023 if(i>=0 && i<BOARD_HEIGHT &&
1024 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1027 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1028 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1029 goto undo_move; /* 2-level break */
1036 if(rf != DROP_RANK) // [HGM] drop
1037 board[rf][ff] = board[rt][ft];
1039 board[rf][ft] = captured;
1040 board[rt][ft] = EmptySquare;
1042 board[rt][ft] = captured;
1046 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1050 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1051 { // [HGM] put drop legality testing in separate routine for clarity
1053 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1054 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1055 n = PieceToNumber(piece);
1056 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1057 return ImpossibleMove; // piece not available
1058 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1059 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1060 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1061 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1062 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1063 if(piece == WhitePawn || piece == BlackPawn) {
1065 for(r=1; r<BOARD_HEIGHT-1; r++)
1066 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1067 // should still test if we mate with this Pawn
1069 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1070 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1072 if( (piece == WhitePawn || piece == BlackPawn) &&
1073 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1074 return IllegalMove; /* no pawn drops on 1st/8th */
1076 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1077 if (!(flags & F_IGNORE_CHECK) &&
1078 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1079 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1082 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1083 int rf, int ff, int rt, int ft,
1087 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1089 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1091 // if (appData.debugMode) {
1092 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1094 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1095 cl->captures++; // [HGM] losers: count legal captures
1096 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1101 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1103 LegalityTestClosure cl; ChessSquare piece, filterPiece, *castlingRights = board[CASTLING];
1105 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1106 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1107 piece = filterPiece = board[rf][ff];
1108 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1110 if (appData.debugMode) {
1112 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1113 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1115 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1116 /* (perhaps we should disallow moves that obviously leave us in check?) */
1117 if(piece == WhiteFalcon || piece == BlackFalcon ||
1118 piece == WhiteCobra || piece == BlackCobra)
1119 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1123 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1124 cl.ft = fFilter = ft;
1125 cl.kind = IllegalMove;
1126 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1127 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1128 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1129 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1130 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1131 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1133 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1134 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1135 if(board[rf][ff] < BlackPawn) { // white
1136 if(rf != 0) return IllegalMove; // must be on back rank
1137 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1139 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1140 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1143 if(gameInfo.variant == VariantShogi) {
1144 /* [HGM] Shogi promotions. '=' means defer */
1145 if(rf != DROP_RANK && cl.kind == NormalMove) {
1146 ChessSquare piece = board[rf][ff];
1148 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1149 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1150 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1151 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1152 promoChar = '+'; // allowed ICS notations
1153 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1154 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1155 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1156 else if(flags & F_WHITE_ON_MOVE) {
1157 if( (int) piece < (int) WhiteWazir &&
1158 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1159 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1160 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1161 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1162 else /* promotion optional, default is defer */
1163 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1164 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1166 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1167 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1168 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1169 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1170 else /* promotion optional, default is defer */
1171 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1172 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1176 if (promoChar != NULLCHAR) {
1177 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1178 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1179 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1180 if(piece == EmptySquare)
1181 cl.kind = ImpossibleMove; // non-existing piece
1182 if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1183 if(promoChar != PieceToChar(BlackKing)) {
1184 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1185 if(piece == BlackLance) cl.kind = ImpossibleMove;
1186 } else { // promotion to King allowed only if we do not haave two yet
1187 int r, f, kings = 0;
1188 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1189 if(kings == 2) cl.kind = IllegalMove;
1191 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1192 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1193 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1194 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1195 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1196 cl.kind = IllegalMove; // promotion to King usually not allowed
1198 cl.kind = IllegalMove;
1208 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1209 int rf, int ff, int rt, int ft,
1213 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1215 register MateTestClosure *cl = (MateTestClosure *) closure;
1220 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1222 MateTest (Board board, int flags)
1225 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1226 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1228 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1229 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1230 nrKing += (board[r][f] == king); // stm has king
1231 if( board[r][f] != EmptySquare ) {
1232 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1237 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1238 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1239 case VariantShatranj:
1240 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1244 if(nrKing == 0) return MT_NOKING;
1247 if(myPieces == 1) return MT_BARE;
1250 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1251 // [HGM] 3check: yet to do!
1253 return inCheck ? MT_CHECK : MT_NONE;
1255 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1256 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1257 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1258 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1259 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1260 if(board[n][holdings] != EmptySquare) {
1261 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1262 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1265 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1266 return myPieces == hisPieces ? MT_STALEMATE :
1267 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1268 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1269 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1271 return inCheck ? MT_CHECKMATE
1272 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1273 MT_STAINMATE : MT_STALEMATE;
1278 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1279 int rf, int ff, int rt, int ft,
1283 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1285 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1286 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1288 // [HGM] wild: for wild-card pieces rt and rf are dummies
1289 if(piece == WhiteFalcon || piece == BlackFalcon ||
1290 piece == WhiteCobra || piece == BlackCobra)
1293 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1294 || PieceToChar(board[rf][ff]) == '~'
1295 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1297 (cl->rfIn == -1 || cl->rfIn == rf) &&
1298 (cl->ffIn == -1 || cl->ffIn == ff) &&
1299 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1300 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1303 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1304 // [HGM] oneclick: if multiple moves, be sure we remember capture
1305 cl->piece = board[rf][ff];
1308 cl->rt = wildCard ? cl->rtIn : rt;
1309 cl->ft = wildCard ? cl->ftIn : ft;
1312 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1317 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1319 int illegal = 0; char c = closure->promoCharIn;
1321 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1322 closure->count = closure->captures = 0;
1323 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1324 closure->kind = ImpossibleMove;
1325 if (appData.debugMode) {
1326 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1327 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1328 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1330 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1331 fFilter = closure->ftIn;
1332 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1333 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1334 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1335 closure->count = closure->captures = 0;
1336 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1337 closure->kind = ImpossibleMove;
1338 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1341 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1342 if (closure->count == 0) {
1343 /* See if it's an illegal move due to check */
1345 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1346 if (closure->count == 0) {
1347 /* No, it's not even that */
1348 if (appData.debugMode) { int i, j;
1349 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1350 for(j=0; j<BOARD_WIDTH; j++)
1351 fprintf(debugFP, "%3d", (int) board[i][j]);
1352 fprintf(debugFP, "\n");
1359 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1360 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1361 if(closure->piece < BlackPawn) { // white
1362 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1363 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1365 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1366 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1369 if(gameInfo.variant == VariantShogi) {
1370 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1371 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1372 ChessSquare piece = closure->piece;
1373 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1374 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1375 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1376 c = '+'; // allowed ICS notations
1377 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1378 else if(flags & F_WHITE_ON_MOVE) {
1379 if( (int) piece < (int) WhiteWazir &&
1380 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1381 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1382 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1383 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1384 else /* promotion optional, default is defer */
1385 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1386 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1388 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1389 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1390 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1391 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1392 else /* promotion optional, default is defer */
1393 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1394 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1397 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1398 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1400 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1401 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1402 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier || gameInfo.variant == VariantMakruk)
1403 c = PieceToChar(BlackFerz);
1404 else if(gameInfo.variant == VariantGreat)
1405 c = PieceToChar(BlackMan);
1406 else if(gameInfo.variant == VariantGrand)
1407 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
1409 c = PieceToChar(BlackQueen);
1410 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1411 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1413 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1414 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1415 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1416 if (closure->count > 1) {
1417 closure->kind = AmbiguousMove;
1420 /* Note: If more than one illegal move matches, but no legal
1421 moves, we return IllegalMove, not AmbiguousMove. Caller
1422 can look at closure->count to detect this.
1424 closure->kind = IllegalMove;
1426 if (appData.debugMode) {
1427 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1428 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1429 closure->promoChar >= ' ' ? closure->promoChar:'-');
1443 } CoordsToAlgebraicClosure;
1445 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1446 ChessMove kind, int rf, int ff,
1447 int rt, int ft, VOIDSTAR closure));
1450 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1452 register CoordsToAlgebraicClosure *cl =
1453 (CoordsToAlgebraicClosure *) closure;
1455 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1456 (board[rf][ff] == cl->piece
1457 || PieceToChar(board[rf][ff]) == '~' &&
1458 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1462 cl->kind = kind; /* this is the move we want */
1464 cl->file++; /* need file to rule out this move */
1468 cl->rank++; /* need rank to rule out this move */
1470 cl->either++; /* rank or file will rule out this move */
1476 /* Convert coordinates to normal algebraic notation.
1477 promoChar must be NULLCHAR or 'x' if not a promotion.
1480 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
1484 char *outp = out, c;
1485 CoordsToAlgebraicClosure cl;
1487 if (rf == DROP_RANK) {
1488 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
1489 /* Bughouse piece drop */
1490 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1495 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1497 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1500 if (promoChar == 'x') promoChar = NULLCHAR;
1501 piece = board[rf][ff];
1502 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1504 if (appData.debugMode)
1505 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1509 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1510 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1511 /* Keep short notation if move is illegal only because it
1512 leaves the player in check, but still return IllegalMove */
1513 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1514 if (kind == IllegalMove) break;
1519 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1520 /* Non-capture; use style "e5" */
1523 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1525 /* Capture; use style "exd5" */
1526 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1527 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1531 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1533 /* Use promotion suffix style "=Q" */
1535 if (appData.debugMode)
1536 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1537 if (promoChar != NULLCHAR) {
1538 if(gameInfo.variant == VariantShogi) {
1539 /* [HGM] ... but not in Shogi! */
1540 *outp++ = promoChar == '=' ? '=' : '+';
1543 *outp++ = ToUpper(promoChar);
1552 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1553 /* Code added by Tord: FRC castling. */
1554 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1555 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1557 safeStrCpy(out, "O-O", MOVE_LEN);
1559 safeStrCpy(out, "O-O-O", MOVE_LEN);
1560 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1562 /* End of code added by Tord */
1563 /* Test for castling or ICS wild castling */
1564 /* Use style "O-O" (oh-oh) for PGN compatibility */
1565 else if (rf == rt &&
1566 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1567 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1568 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1569 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1570 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1571 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1573 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1575 /* This notation is always unambiguous, unless there are
1576 kings on both the d and e files, with "wild castling"
1577 possible for the king on the d file and normal castling
1578 possible for the other. ICS rules for wild 9
1579 effectively make castling illegal for either king in
1580 this situation. So I am not going to worry about it;
1581 I'll just generate an ambiguous O-O in this case.
1583 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1586 /* else fall through */
1591 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1592 cl.ft = fFilter = ft;
1594 cl.kind = IllegalMove;
1595 cl.rank = cl.file = cl.either = 0;
1596 c = PieceToChar(piece) ;
1597 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
1599 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1600 /* Generate pretty moves for moving into check, but
1601 still return IllegalMove.
1603 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
1604 if (cl.kind == IllegalMove) break;
1605 cl.kind = IllegalMove;
1608 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1609 else "Ngf3" or "Ngxf7",
1610 else "N1f3" or "N5xf7",
1611 else "Ng1f3" or "Ng5xf7".
1613 if( c == '~' || c == '+') {
1614 /* [HGM] print nonexistent piece as its demoted version */
1615 piece = (ChessSquare) (DEMOTED piece);
1617 if(c=='+') *outp++ = c;
1618 *outp++ = ToUpper(PieceToChar(piece));
1620 if (cl.file || (cl.either && !cl.rank)) {
1626 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1629 if(board[rt][ft] != EmptySquare)
1635 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1636 if (gameInfo.variant == VariantShogi) {
1637 /* [HGM] in Shogi non-pawns can promote */
1638 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1640 else if (gameInfo.variant != VariantSuper && promoChar &&
1641 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
1643 *outp++ = ToUpper(promoChar);
1645 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1647 *outp++ = ToUpper(promoChar);
1653 /* Moving a nonexistent piece */
1657 /* Not a legal move, even ignoring check.
1658 If there was a piece on the from square,
1659 use style "Ng1g3" or "Ng1xe8";
1660 if there was a pawn or nothing (!),
1661 use style "g1g3" or "g1xe8". Use "x"
1662 if a piece was on the to square, even
1663 a piece of the same color.
1667 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1669 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1670 c += (board[r][f] == piece); // count on-board pieces of given type
1671 *outp++ = ToUpper(PieceToChar(piece));
1673 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1677 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1679 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1683 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1684 /* Use promotion suffix style "=Q" */
1685 if (promoChar != NULLCHAR && promoChar != 'x') {
1687 *outp++ = ToUpper(promoChar);
1694 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1703 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1705 int preyStackPointer, chaseStackPointer;
1708 unsigned char rf, ff, rt, ft;
1712 unsigned char rank, file;
1718 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1720 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1721 int rf, int ff, int rt, int ft,
1725 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1726 { // For adding captures that can lead to chase indictment to the chaseStack
1727 if(board[rt][ft] == EmptySquare) return; // non-capture
1728 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1729 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1730 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1731 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1732 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1733 chaseStack[chaseStackPointer].rf = rf;
1734 chaseStack[chaseStackPointer].ff = ff;
1735 chaseStack[chaseStackPointer].rt = rt;
1736 chaseStack[chaseStackPointer].ft = ft;
1737 chaseStackPointer++;
1740 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1741 int rf, int ff, int rt, int ft,
1745 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1746 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1748 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1750 if(board[rt][ft] == EmptySquare) return; // no capture
1751 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1752 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1754 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1755 for(i=0; i<chaseStackPointer; i++) {
1756 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1757 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1758 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1759 chaseStack[i] = chaseStack[--chaseStackPointer];
1765 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1766 int rf, int ff, int rt, int ft,
1770 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1771 { // for determining if a piece (given through the closure) is protected
1772 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1774 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1775 if(appData.debugMode && board[rt][ft] != EmptySquare)
1776 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1779 extern char moveList[MAX_MOVES][MOVE_LEN];
1782 PerpetualChase (int first, int last)
1783 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1786 ChessSquare captured;
1788 preyStackPointer = 0; // clear stack of chased pieces
1789 for(i=first; i<last; i+=2) { // for all positions with same side to move
1790 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1791 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1792 // determine all captures possible after the move, and put them on chaseStack
1793 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
1794 if(appData.debugMode) { int n;
1795 for(n=0; n<chaseStackPointer; n++)
1796 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1797 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1798 fprintf(debugFP, ": all capts\n");
1800 // determine all captures possible before the move, and delete them from chaseStack
1801 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1802 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1803 cl.rt = moveList[i][3]-ONE;
1804 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1805 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
1806 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
1807 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
1808 if(appData.debugMode) { int n;
1809 for(n=0; n<chaseStackPointer; n++)
1810 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1811 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1812 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1814 // chaseSack now contains all captures made possible by the move
1815 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1816 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1817 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1819 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1820 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1822 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1823 continue; // C or H attack on R is always chase; leave on chaseStack
1825 if(attacker == victim) {
1826 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1827 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1828 // we can capture back with equal piece, so this is no chase but a sacrifice
1829 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1830 j--; /* ! */ continue;
1835 // the attack is on a lower piece, or on a pinned or blocked equal one
1836 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
1837 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
1838 // test if the victim is protected by a true protector. First make the capture.
1839 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1840 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1841 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1842 // Then test if the opponent can recapture
1843 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1844 cl.rt = chaseStack[j].rt;
1845 cl.ft = chaseStack[j].ft;
1846 if(appData.debugMode) {
1847 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1849 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
1850 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
1851 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
1852 // unmake the capture
1853 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1854 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1855 // if a recapture was found, piece is protected, and we are not chasing it.
1856 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1857 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1861 // chaseStack now contains all moves that chased
1862 if(appData.debugMode) { int n;
1863 for(n=0; n<chaseStackPointer; n++)
1864 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1865 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1866 fprintf(debugFP, ": chases\n");
1868 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1869 for(j=0; j<chaseStackPointer; j++) {
1870 preyStack[j].rank = chaseStack[j].rt;
1871 preyStack[j].file = chaseStack[j].ft;
1873 preyStackPointer = chaseStackPointer;
1876 for(j=0; j<chaseStackPointer; j++) {
1877 for(k=0; k<preyStackPointer; k++) {
1878 // search the victim of each chase move on the preyStack (first occurrence)
1879 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1880 if(k < tail) break; // piece was already identified as still being chased
1881 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1882 preyStack[tail] = preyStack[k]; // by swapping
1883 preyStack[k] = preyStack[preyStackPointer];
1889 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1890 if(appData.debugMode) { int n;
1891 for(n=0; n<preyStackPointer; n++)
1892 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1893 fprintf(debugFP, "always chased upto ply %d\n", i);
1895 // now adjust the location of the chased pieces according to opponent move
1896 for(j=0; j<preyStackPointer; j++) {
1897 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1898 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1899 preyStack[j].rank = moveList[i+1][3]-ONE;
1900 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1905 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
1906 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the