2 * moves.c - Move generation and checking
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
10 * Enhancements Copyright 2005 Alessandro Scotti
12 * The following terms apply to Digital Equipment Corporation's copyright
14 * ------------------------------------------------------------------------
17 * Permission to use, copy, modify, and distribute this software and its
18 * documentation for any purpose and without fee is hereby granted,
19 * provided that the above copyright notice appear in all copies and that
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
59 #else /* not HAVE_STRING_H */
61 #endif /* not HAVE_STRING_H */
67 int WhitePiece P((ChessSquare));
68 int BlackPiece P((ChessSquare));
69 int SameColor P((ChessSquare, ChessSquare));
70 int PosFlags(int index);
72 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
78 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
84 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
87 int SameColor(piece1, piece2)
88 ChessSquare piece1, piece2;
90 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
91 (int) piece1 < (int) BlackPawn &&
92 (int) piece2 >= (int) WhitePawn &&
93 (int) piece2 < (int) BlackPawn)
94 || ((int) piece1 >= (int) BlackPawn &&
95 (int) piece1 < (int) EmptySquare &&
96 (int) piece2 >= (int) BlackPawn &&
97 (int) piece2 < (int) EmptySquare);
100 char pieceToChar[] = {
101 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
102 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
103 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
104 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
106 char pieceNickName[EmptySquare];
111 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
112 return pieceToChar[(int) p];
115 int PieceToNumber(p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
119 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
121 while(start++ != p) if(pieceToChar[(int)start-1] != '.') i++;
125 ChessSquare CharToPiece(c)
129 for(i=0; i< (int) EmptySquare; i++)
130 if(pieceNickName[i] == c) return (ChessSquare) i;
131 for(i=0; i< (int) EmptySquare; i++)
132 if(pieceToChar[i] == c) return (ChessSquare) i;
136 void CopyBoard(to, from)
141 for (i = 0; i < BOARD_HEIGHT; i++)
142 for (j = 0; j < BOARD_WIDTH; j++)
143 to[i][j] = from[i][j];
144 for (j = 0; j < BOARD_FILES-1; j++) // [HGM] gamestate: copy castling rights and ep status
145 to[CASTLING][j] = from[CASTLING][j];
146 to[HOLDINGS_SET] = 0; // flag used in ICS play
149 int CompareBoards(board1, board2)
150 Board board1, board2;
154 for (i = 0; i < BOARD_HEIGHT; i++)
155 for (j = 0; j < BOARD_WIDTH; j++) {
156 if (board1[i][j] != board2[i][j])
163 /* Call callback once for each pseudo-legal move in the given
164 position, except castling moves. A move is pseudo-legal if it is
165 legal, or if it would be legal except that it leaves the king in
166 check. In the arguments, epfile is EP_NONE if the previous move
167 was not a double pawn push, or the file 0..7 if it was, or
168 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
169 Promotion moves generated are to Queen only.
171 void GenPseudoLegal(board, flags, callback, closure)
174 MoveCallback callback;
178 int i, j, d, s, fs, rs, rt, ft, m;
179 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
180 int promoRank = gameInfo.variant == VariantMakruk ? 3 : 1;
182 for (rf = 0; rf < BOARD_HEIGHT; rf++)
183 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
186 if (flags & F_WHITE_ON_MOVE) {
187 if (!WhitePiece(board[rf][ff])) continue;
189 if (!BlackPiece(board[rf][ff])) continue;
191 m = 0; piece = board[rf][ff];
192 if(PieceToChar(piece) == '~')
193 piece = (ChessSquare) ( DEMOTED piece );
194 if(gameInfo.variant == VariantShogi)
195 piece = (ChessSquare) ( SHOGI piece );
198 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
200 /* can't happen ([HGM] except for faries...) */
204 if(gameInfo.variant == VariantXiangqi) {
205 /* [HGM] capture and move straight ahead in Xiangqi */
206 if (rf < BOARD_HEIGHT-1 &&
207 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
208 callback(board, flags, NormalMove,
209 rf, ff, rf + 1, ff, closure);
211 /* and move sideways when across the river */
212 for (s = -1; s <= 1; s += 2) {
213 if (rf >= BOARD_HEIGHT>>1 &&
214 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
215 !WhitePiece(board[rf][ff+s]) ) {
216 callback(board, flags, NormalMove,
217 rf, ff, rf, ff+s, closure);
222 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
223 callback(board, flags,
224 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
225 rf, ff, rf + 1, ff, closure);
227 if (rf == 1 && board[2][ff] == EmptySquare &&
228 gameInfo.variant != VariantShatranj && /* [HGM] */
229 gameInfo.variant != VariantCourier && /* [HGM] */
230 board[3][ff] == EmptySquare ) {
231 callback(board, flags, NormalMove,
232 rf, ff, 3, ff, closure);
234 for (s = -1; s <= 1; s += 2) {
235 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
236 ((flags & F_KRIEGSPIEL_CAPTURE) ||
237 BlackPiece(board[rf + 1][ff + s]))) {
238 callback(board, flags,
239 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
240 rf, ff, rf + 1, ff + s, closure);
242 if (rf == BOARD_HEIGHT-4) {
243 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
244 (epfile == ff + s || epfile == EP_UNKNOWN) &&
245 board[BOARD_HEIGHT-4][ff + s] == BlackPawn &&
246 board[BOARD_HEIGHT-3][ff + s] == EmptySquare) {
247 callback(board, flags, WhiteCapturesEnPassant,
248 rf, ff, 5, ff + s, closure);
255 if(gameInfo.variant == VariantXiangqi) {
256 /* [HGM] capture straight ahead in Xiangqi */
257 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
258 callback(board, flags, NormalMove,
259 rf, ff, rf - 1, ff, closure);
261 /* and move sideways when across the river */
262 for (s = -1; s <= 1; s += 2) {
263 if (rf < BOARD_HEIGHT>>1 &&
264 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
265 !BlackPiece(board[rf][ff+s]) ) {
266 callback(board, flags, NormalMove,
267 rf, ff, rf, ff+s, closure);
272 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
273 callback(board, flags,
274 rf <= promoRank ? BlackPromotion : NormalMove,
275 rf, ff, rf - 1, ff, closure);
277 if (rf == BOARD_HEIGHT-2 && board[BOARD_HEIGHT-3][ff] == EmptySquare &&
278 gameInfo.variant != VariantShatranj && /* [HGM] */
279 gameInfo.variant != VariantCourier && /* [HGM] */
280 board[BOARD_HEIGHT-4][ff] == EmptySquare) {
281 callback(board, flags, NormalMove,
282 rf, ff, BOARD_HEIGHT-4, ff, closure);
284 for (s = -1; s <= 1; s += 2) {
285 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
286 ((flags & F_KRIEGSPIEL_CAPTURE) ||
287 WhitePiece(board[rf - 1][ff + s]))) {
288 callback(board, flags,
289 rf <= promoRank ? BlackPromotion : NormalMove,
290 rf, ff, rf - 1, ff + s, closure);
293 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
294 (epfile == ff + s || epfile == EP_UNKNOWN) &&
295 board[3][ff + s] == WhitePawn &&
296 board[2][ff + s] == EmptySquare) {
297 callback(board, flags, BlackCapturesEnPassant,
298 rf, ff, 2, ff + s, closure);
309 for (i = -1; i <= 1; i += 2)
310 for (j = -1; j <= 1; j += 2)
311 for (s = 1; s <= 2; s++) {
314 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
315 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
316 && !SameColor(board[rf][ff], board[rt][ft]))
317 callback(board, flags, NormalMove,
318 rf, ff, rt, ft, closure);
322 case SHOGI WhiteKnight:
323 for (s = -1; s <= 1; s += 2) {
324 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
325 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
326 callback(board, flags, NormalMove,
327 rf, ff, rf + 2, ff + s, closure);
332 case SHOGI BlackKnight:
333 for (s = -1; s <= 1; s += 2) {
334 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
335 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
336 callback(board, flags, NormalMove,
337 rf, ff, rf - 2, ff + s, closure);
344 for (d = 0; d <= 1; d++)
345 for (s = -1; s <= 1; s += 2) {
348 rt = rf + (i * s) * d;
349 ft = ff + (i * s) * (1 - d);
350 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
351 if (m == 0 && board[rt][ft] == EmptySquare)
352 callback(board, flags, NormalMove,
353 rf, ff, rt, ft, closure);
354 if (m == 1 && board[rt][ft] != EmptySquare &&
355 !SameColor(board[rf][ff], board[rt][ft]) )
356 callback(board, flags, NormalMove,
357 rf, ff, rt, ft, closure);
358 if (board[rt][ft] != EmptySquare && m++) break;
363 /* Gold General (and all its promoted versions) . First do the */
364 /* diagonal forward steps, then proceed as normal Wazir */
365 case SHOGI WhiteWazir:
366 case SHOGI (PROMOTED WhitePawn):
367 case SHOGI (PROMOTED WhiteKnight):
368 case SHOGI (PROMOTED WhiteQueen):
369 case SHOGI (PROMOTED WhiteFerz):
370 for (s = -1; s <= 1; s += 2) {
371 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
372 !SameColor(board[rf][ff], board[rf + 1][ff + s])) {
373 callback(board, flags, NormalMove,
374 rf, ff, rf + 1, ff + s, closure);
379 case SHOGI BlackWazir:
380 case SHOGI (PROMOTED BlackPawn):
381 case SHOGI (PROMOTED BlackKnight):
382 case SHOGI (PROMOTED BlackQueen):
383 case SHOGI (PROMOTED BlackFerz):
384 for (s = -1; s <= 1; s += 2) {
385 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
386 !SameColor(board[rf][ff], board[rf - 1][ff + s])) {
387 callback(board, flags, NormalMove,
388 rf, ff, rf - 1, ff + s, closure);
395 for (d = 0; d <= 1; d++)
396 for (s = -1; s <= 1; s += 2) {
398 ft = ff + s * (1 - d);
399 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
400 && !SameColor(board[rf][ff], board[rt][ft]) &&
401 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
402 callback(board, flags, NormalMove,
403 rf, ff, rt, ft, closure);
409 /* [HGM] support Shatranj pieces */
410 for (rs = -1; rs <= 1; rs += 2)
411 for (fs = -1; fs <= 1; fs += 2) {
414 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
415 && ( gameInfo.variant != VariantXiangqi ||
416 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
418 && !SameColor(board[rf][ff], board[rt][ft]))
419 callback(board, flags, NormalMove,
420 rf, ff, rt, ft, closure);
421 if(gameInfo.variant != VariantFairy && gameInfo.variant != VariantGreat) continue;
422 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
424 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
425 && !SameColor(board[rf][ff], board[rt][ft]))
426 callback(board, flags, NormalMove,
427 rf, ff, rt, ft, closure);
431 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
432 case SHOGI WhiteCardinal:
433 case SHOGI BlackCardinal:
436 /* Capablanca Archbishop continues as Knight */
441 /* Shogi Bishops are ordinary Bishops */
442 case SHOGI WhiteBishop:
443 case SHOGI BlackBishop:
446 for (rs = -1; rs <= 1; rs += 2)
447 for (fs = -1; fs <= 1; fs += 2)
451 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
452 if (SameColor(board[rf][ff], board[rt][ft])) break;
453 callback(board, flags, NormalMove,
454 rf, ff, rt, ft, closure);
455 if (board[rt][ft] != EmptySquare) break;
457 if(m==1) goto mounted;
458 if(m==2) goto finishGold;
459 /* Bishop falls through */
462 /* Shogi Lance is unlike anything, and asymmetric at that */
463 case SHOGI WhiteQueen:
467 if (rt >= BOARD_HEIGHT) break;
468 if (SameColor(board[rf][ff], board[rt][ft])) break;
469 callback(board, flags, NormalMove,
470 rf, ff, rt, ft, closure);
471 if (board[rt][ft] != EmptySquare) break;
475 case SHOGI BlackQueen:
480 if (SameColor(board[rf][ff], board[rt][ft])) break;
481 callback(board, flags, NormalMove,
482 rf, ff, rt, ft, closure);
483 if (board[rt][ft] != EmptySquare) break;
487 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
490 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
491 for (s = -2; s <= 2; s += 4) {
493 ft = ff + s * (1 - d);
494 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT || board[rf+rt>>1][ff+ft>>1] == EmptySquare) continue;
495 if (SameColor(board[rf][ff], board[rt][ft])) continue;
496 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
500 /* Shogi Dragon King has to continue as Ferz after Rook moves */
501 case SHOGI WhiteDragon:
502 case SHOGI BlackDragon:
505 /* Capablanca Chancellor sets flag to continue as Knight */
510 /* Shogi Rooks are ordinary Rooks */
511 case SHOGI WhiteRook:
512 case SHOGI BlackRook:
516 for (d = 0; d <= 1; d++)
517 for (s = -1; s <= 1; s += 2)
519 rt = rf + (i * s) * d;
520 ft = ff + (i * s) * (1 - d);
521 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
522 if (SameColor(board[rf][ff], board[rt][ft])) break;
523 callback(board, flags, NormalMove,
524 rf, ff, rt, ft, closure);
525 if (board[rt][ft] != EmptySquare) break;
527 if(m==1) goto mounted;
528 if(m==2) goto finishSilver;
533 for (rs = -1; rs <= 1; rs++)
534 for (fs = -1; fs <= 1; fs++) {
535 if (rs == 0 && fs == 0) continue;
539 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
540 if (SameColor(board[rf][ff], board[rt][ft])) break;
541 callback(board, flags, NormalMove,
542 rf, ff, rt, ft, closure);
543 if (board[rt][ft] != EmptySquare) break;
548 /* Shogi Pawn and Silver General: first the Pawn move, */
549 /* then the General continues like a Ferz */
551 if(gameInfo.variant != VariantMakruk) goto commoner;
552 case SHOGI WhitePawn:
553 case SHOGI WhiteFerz:
554 if (rf < BOARD_HEIGHT-1 &&
555 !SameColor(board[rf][ff], board[rf + 1][ff]) )
556 callback(board, flags, NormalMove,
557 rf, ff, rf + 1, ff, closure);
558 if(piece != SHOGI WhitePawn) goto finishSilver;
562 if(gameInfo.variant != VariantMakruk) goto commoner;
563 case SHOGI BlackPawn:
564 case SHOGI BlackFerz:
566 !SameColor(board[rf][ff], board[rf - 1][ff]) )
567 callback(board, flags, NormalMove,
568 rf, ff, rf - 1, ff, closure);
569 if(piece == SHOGI BlackPawn) break;
574 /* [HGM] support Shatranj pieces */
575 for (rs = -1; rs <= 1; rs += 2)
576 for (fs = -1; fs <= 1; fs += 2) {
579 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
580 if (!SameColor(board[rf][ff], board[rt][ft]) &&
581 (gameInfo.variant != VariantXiangqi || InPalace(rt, ft) ) )
582 callback(board, flags, NormalMove,
583 rf, ff, rt, ft, closure);
589 m++; // [HGM] superchess: use for Centaur
591 case SHOGI WhiteKing:
592 case SHOGI BlackKing:
596 for (i = -1; i <= 1; i++)
597 for (j = -1; j <= 1; j++) {
598 if (i == 0 && j == 0) continue;
601 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
602 if (SameColor(board[rf][ff], board[rt][ft])) continue;
603 callback(board, flags, NormalMove,
604 rf, ff, rt, ft, closure);
606 if(m==1) goto mounted;
609 case WhiteNightrider:
610 case BlackNightrider:
611 for (i = -1; i <= 1; i += 2)
612 for (j = -1; j <= 1; j += 2)
613 for (s = 1; s <= 2; s++) { int k;
617 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
618 if (SameColor(board[rf][ff], board[rt][ft])) break;
619 callback(board, flags, NormalMove,
620 rf, ff, rt, ft, closure);
621 if (board[rt][ft] != EmptySquare) break;
626 // Use Lance as Berolina / Spartan Pawn.
628 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
629 callback(board, flags,
630 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
631 rf, ff, rf + 1, ff, closure);
632 for (s = -1; s <= 1; s += 2) {
633 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
634 callback(board, flags,
635 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
636 rf, ff, rf + 1, ff + s, closure);
637 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
638 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
643 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
644 callback(board, flags,
645 rf <= promoRank ? BlackPromotion : NormalMove,
646 rf, ff, rf - 1, ff, closure);
647 for (s = -1; s <= 1; s += 2) {
648 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
649 callback(board, flags,
650 rf <= promoRank ? BlackPromotion : NormalMove,
651 rf, ff, rf - 1, ff + s, closure);
652 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
653 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
657 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
661 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
674 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
675 int rf, int ff, int rt, int ft,
678 void GenLegalCallback(board, flags, kind, rf, ff, rt, ft, closure)
685 register GenLegalClosure *cl = (GenLegalClosure *) closure;
687 if (!(flags & F_IGNORE_CHECK) &&
688 CheckTest(board, flags, rf, ff, rt, ft,
689 kind == WhiteCapturesEnPassant ||
690 kind == BlackCapturesEnPassant)) return;
691 if (flags & F_ATOMIC_CAPTURE) {
692 if (board[rt][ft] != EmptySquare ||
693 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
695 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
696 if (board[rf][ff] == king) return;
697 for (r = rt-1; r <= rt+1; r++) {
698 for (f = ft-1; f <= ft+1; f++) {
699 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
700 board[r][f] == king) return;
705 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
712 int captures; // [HGM] losers
713 } LegalityTestClosure;
716 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
717 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
718 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
719 moves that would destroy your own king. The CASTLE_OK flags are
720 true if castling is not yet ruled out by a move of the king or
721 rook. Return TRUE if the player on move is currently in check and
722 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
723 int GenLegal(board, flags, callback, closure)
726 MoveCallback callback;
730 int ff, ft, k, left, right, swap;
731 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
732 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
736 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl);
739 CheckTest(board, flags, -1, -1, -1, -1, FALSE)) return TRUE;
741 /* Generate castling moves */
742 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
743 wKing = WhiteUnicorn; bKing = BlackUnicorn;
746 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
747 if ((flags & F_WHITE_ON_MOVE) &&
748 (flags & F_WHITE_KCASTLE_OK) &&
749 board[0][ff] == wKing &&
750 board[0][ff + 1] == EmptySquare &&
751 board[0][ff + 2] == EmptySquare &&
752 board[0][BOARD_RGHT-3] == EmptySquare &&
753 board[0][BOARD_RGHT-2] == EmptySquare &&
754 board[0][BOARD_RGHT-1] == WhiteRook &&
755 castlingRights[0] != NoRights && /* [HGM] check rights */
756 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
758 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
759 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
760 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
761 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
763 callback(board, flags,
764 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
765 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
767 if ((flags & F_WHITE_ON_MOVE) &&
768 (flags & F_WHITE_QCASTLE_OK) &&
769 board[0][ff] == wKing &&
770 board[0][ff - 1] == EmptySquare &&
771 board[0][ff - 2] == EmptySquare &&
772 board[0][BOARD_LEFT+2] == EmptySquare &&
773 board[0][BOARD_LEFT+1] == EmptySquare &&
774 board[0][BOARD_LEFT+0] == WhiteRook &&
775 castlingRights[1] != NoRights && /* [HGM] check rights */
776 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
778 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
779 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
780 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
782 callback(board, flags,
783 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
784 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
786 if (!(flags & F_WHITE_ON_MOVE) &&
787 (flags & F_BLACK_KCASTLE_OK) &&
788 board[BOARD_HEIGHT-1][ff] == bKing &&
789 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
790 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
791 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
792 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
793 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
794 castlingRights[3] != NoRights && /* [HGM] check rights */
795 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
797 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
798 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
799 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
800 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
802 callback(board, flags,
803 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
804 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
806 if (!(flags & F_WHITE_ON_MOVE) &&
807 (flags & F_BLACK_QCASTLE_OK) &&
808 board[BOARD_HEIGHT-1][ff] == bKing &&
809 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
810 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
811 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
812 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
813 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
814 castlingRights[4] != NoRights && /* [HGM] check rights */
815 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
817 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
818 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
819 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
821 callback(board, flags,
822 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
823 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
827 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
829 /* generate all potential FRC castling moves (KxR), ignoring flags */
830 /* [HGM] test if the Rooks we find have castling rights */
831 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
834 if ((flags & F_WHITE_ON_MOVE) != 0) {
835 ff = castlingRights[2]; /* King file if we have any rights */
836 if(ff != NoRights && board[0][ff] == WhiteKing) {
837 if (appData.debugMode) {
838 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
839 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
841 ft = castlingRights[0]; /* Rook file if we have H-side rights */
843 right = BOARD_RGHT-2;
844 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
845 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
846 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
847 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
848 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
849 if(ft != NoRights && board[0][ft] == WhiteRook)
850 callback(board, flags, WhiteHSideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
852 ft = castlingRights[1]; /* Rook file if we have A-side rights */
855 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
856 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
857 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
858 if(ff > BOARD_LEFT+2)
859 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
860 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
861 if(ft != NoRights && board[0][ft] == WhiteRook)
862 callback(board, flags, WhiteASideCastleFR, 0, swap ? ft : ff, 0, swap ? ff : ft, closure);
865 ff = castlingRights[5]; /* King file if we have any rights */
866 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
867 ft = castlingRights[3]; /* Rook file if we have H-side rights */
869 right = BOARD_RGHT-2;
870 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
871 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
872 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
873 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
874 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
875 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
876 callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
878 ft = castlingRights[4]; /* Rook file if we have A-side rights */
881 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
882 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
883 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
884 if(ff > BOARD_LEFT+2)
885 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
886 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
887 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook)
888 callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, swap ? ft : ff, BOARD_HEIGHT-1, swap ? ff : ft, closure);
904 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
905 int rf, int ff, int rt, int ft,
909 void CheckTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
916 register CheckTestClosure *cl = (CheckTestClosure *) closure;
918 if (rt == cl->rking && ft == cl->fking) cl->check++;
922 /* If the player on move were to move from (rf, ff) to (rt, ft), would
923 he leave himself in check? Or if rf == -1, is the player on move
924 in check now? enPassant must be TRUE if the indicated move is an
925 e.p. capture. The possibility of castling out of a check along the
926 back rank is not accounted for (i.e., we still return nonzero), as
927 this is illegal anyway. Return value is the number of times the
929 int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
932 int rf, ff, rt, ft, enPassant;
935 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
936 ChessSquare captured = EmptySquare;
937 /* Suppress warnings on uninitialized variables */
939 if(gameInfo.variant == VariantXiangqi)
940 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
941 if(gameInfo.variant == VariantKnightmate)
942 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
946 captured = board[rf][ft];
947 board[rf][ft] = EmptySquare;
949 captured = board[rt][ft];
951 board[rt][ft] = board[rf][ff];
952 board[rf][ff] = EmptySquare;
953 } else board[rt][ft] = ff; // [HGM] drop
955 /* For compatibility with ICS wild 9, we scan the board in the
956 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
957 and we test only whether that one is in check. */
959 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
960 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
961 if (board[cl.rking][cl.fking] == king) {
962 if(gameInfo.variant == VariantXiangqi) {
963 /* [HGM] In Xiangqi opposing Kings means check as well */
965 dir = (king >= BlackPawn) ? -1 : 1;
966 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
967 board[i][cl.fking] == EmptySquare; i+=dir );
968 if(i>=0 && i<BOARD_HEIGHT &&
969 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
973 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl);
974 goto undo_move; /* 2-level break */
981 board[rf][ff] = board[rt][ft];
983 board[rf][ft] = captured;
984 board[rt][ft] = EmptySquare;
986 board[rt][ft] = captured;
988 } else board[rt][ft] = EmptySquare; // [HGM] drop
990 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
993 ChessMove LegalDrop(board, flags, piece, rt, ft)
998 { // [HGM] put drop legality testing in separate routine for clarity
1000 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1001 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1002 n = PieceToNumber(piece);
1003 if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1004 return ImpossibleMove; // piece not available
1005 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1006 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1007 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1008 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1009 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1010 if(piece == WhitePawn || piece == BlackPawn) {
1012 for(r=1; r<BOARD_HEIGHT-1; r++)
1013 if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
1014 // should still test if we mate with this Pawn
1017 if( (piece == WhitePawn || piece == BlackPawn) &&
1018 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1019 return IllegalMove; /* no pawn drops on 1st/8th */
1021 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1022 if (!(flags & F_IGNORE_CHECK) &&
1023 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1024 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1027 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1028 int rf, int ff, int rt, int ft,
1031 void LegalityTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1038 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1040 // if (appData.debugMode) {
1041 // fprintf(debugFP, "Legality test: %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1043 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1044 cl->captures++; // [HGM] losers: count legal captures
1045 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1049 ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
1052 int rf, ff, rt, ft, promoChar;
1054 LegalityTestClosure cl; ChessSquare piece, *castlingRights = board[CASTLING];
1056 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1057 piece = board[rf][ff];
1059 if (appData.debugMode) {
1061 for(i=0; i<6; i++) fprintf(debugFP, "%d ", castlingRights[i]);
1062 fprintf(debugFP, "Legality test? %c%c%c%c\n", ff+AAA, rf+ONE, ft+AAA, rt+ONE);
1064 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1065 /* (perhaps we should disallow moves that obviously leave us in check?) */
1066 if(piece == WhiteFalcon || piece == BlackFalcon ||
1067 piece == WhiteCobra || piece == BlackCobra)
1068 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1074 cl.kind = IllegalMove;
1075 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1076 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl);
1077 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1078 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1079 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1081 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1082 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1083 if(board[rf][ff] < BlackPawn) { // white
1084 if(rf != 0) return IllegalMove; // must be on back rank
1085 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1087 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1088 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1091 if(gameInfo.variant == VariantShogi) {
1092 /* [HGM] Shogi promotions. '=' means defer */
1093 if(rf != DROP_RANK && cl.kind == NormalMove) {
1094 ChessSquare piece = board[rf][ff];
1096 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1097 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1098 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1099 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1100 promoChar = '+'; // allowed ICS notations
1101 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1102 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1103 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1104 else if(flags & F_WHITE_ON_MOVE) {
1105 if( (int) piece < (int) WhiteWazir &&
1106 (rf >= BOARD_HEIGHT*2/3 || rt >= BOARD_HEIGHT*2/3) ) {
1107 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1108 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1109 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1110 else /* promotion optional, default is defer */
1111 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1112 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1114 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1115 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1116 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1117 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1118 else /* promotion optional, default is defer */
1119 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1120 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1124 if (promoChar != NULLCHAR) {
1125 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1126 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1127 if(CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar)) == EmptySquare)
1128 cl.kind = ImpossibleMove; // non-existing piece
1130 cl.kind = IllegalMove;
1140 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1141 int rf, int ff, int rt, int ft,
1144 void MateTestCallback(board, flags, kind, rf, ff, rt, ft, closure)
1151 register MateTestClosure *cl = (MateTestClosure *) closure;
1156 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1157 int MateTest(board, flags)
1162 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1163 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1165 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1166 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1167 nrKing += (board[r][f] == king); // stm has king
1168 if( board[r][f] != EmptySquare ) {
1169 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1174 if(appData.debugMode) fprintf(debugFP, "MateTest: K=%d, my=%d, his=%d\n", nrKing, myPieces, hisPieces);
1175 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1176 case VariantShatranj:
1177 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1181 if(nrKing == 0) return MT_NOKING;
1184 if(myPieces == 1) return MT_BARE;
1187 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl);
1188 // [HGM] 3check: yet to do!
1190 return inCheck ? MT_CHECK : MT_NONE;
1192 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper || gameInfo.variant != VariantGreat) { // drop game
1193 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1194 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1195 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1196 if(board[n][holdings] != EmptySquare) {
1197 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1198 if(moveType == WhiteDrop || moveType == BlackDrop) return MT_CHECK; // we can resolve check by legal drop
1201 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1202 return myPieces == hisPieces ? MT_STALEMATE :
1203 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1204 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1205 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1207 return inCheck ? MT_CHECKMATE
1208 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj) ?
1209 MT_STAINMATE : MT_STALEMATE;
1214 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1215 int rf, int ff, int rt, int ft,
1218 void DisambiguateCallback(board, flags, kind, rf, ff, rt, ft, closure)
1225 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1226 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1228 // [HGM] wild: for wild-card pieces rt and rf are dummies
1229 if(piece == WhiteFalcon || piece == BlackFalcon ||
1230 piece == WhiteCobra || piece == BlackCobra)
1233 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1234 || PieceToChar(board[rf][ff]) == '~'
1235 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1237 (cl->rfIn == -1 || cl->rfIn == rf) &&
1238 (cl->ffIn == -1 || cl->ffIn == ff) &&
1239 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1240 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1243 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1244 // [HGM] oneclick: if multiple moves, be sure we remember capture
1245 cl->piece = board[rf][ff];
1248 cl->rt = wildCard ? cl->rtIn : rt;
1249 cl->ft = wildCard ? cl->ftIn : ft;
1252 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1256 void Disambiguate(board, flags, closure)
1259 DisambiguateClosure *closure;
1261 int illegal = 0; char c = closure->promoCharIn;
1263 closure->count = closure->captures = 0;
1264 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1265 closure->kind = ImpossibleMove;
1266 if (appData.debugMode) {
1267 fprintf(debugFP, "Disambiguate in: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1268 closure->pieceIn,closure->ffIn,closure->rfIn,closure->ftIn,closure->rtIn,
1269 closure->promoCharIn, closure->promoCharIn >= ' ' ? closure->promoCharIn : '-');
1271 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure);
1272 if (closure->count == 0) {
1273 /* See if it's an illegal move due to check */
1275 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure);
1276 if (closure->count == 0) {
1277 /* No, it's not even that */
1278 if (appData.debugMode) { int i, j;
1279 for(i=BOARD_HEIGHT-1; i>=0; i--) {
1280 for(j=0; j<BOARD_WIDTH; j++)
1281 fprintf(debugFP, "%3d", (int) board[i][j]);
1282 fprintf(debugFP, "\n");
1289 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
1290 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
1291 if(closure->piece < BlackPawn) { // white
1292 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
1293 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
1295 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
1296 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
1299 if(gameInfo.variant == VariantShogi) {
1300 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
1301 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
1302 ChessSquare piece = closure->piece;
1303 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1304 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1305 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1306 c = '+'; // allowed ICS notations
1307 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
1308 else if(flags & F_WHITE_ON_MOVE) {
1309 if( (int) piece < (int) WhiteWazir &&
1310 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
1311 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
1312 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
1313 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
1314 else /* promotion optional, default is defer */
1315 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
1316 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1318 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
1319 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
1320 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
1321 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
1322 else /* promotion optional, default is defer */
1323 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
1324 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
1327 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
1328 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
1330 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
1331 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
1332 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier || gameInfo.variant == VariantMakruk)
1333 c = PieceToChar(BlackFerz);
1334 else if(gameInfo.variant == VariantGreat)
1335 c = PieceToChar(BlackMan);
1337 c = PieceToChar(BlackQueen);
1338 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
1339 } else if (c != NULLCHAR) closure->kind = IllegalMove;
1341 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
1342 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
1343 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
1344 if (closure->count > 1) {
1345 closure->kind = AmbiguousMove;
1348 /* Note: If more than one illegal move matches, but no legal
1349 moves, we return IllegalMove, not AmbiguousMove. Caller
1350 can look at closure->count to detect this.
1352 closure->kind = IllegalMove;
1354 if (appData.debugMode) {
1355 fprintf(debugFP, "Disambiguate out: %d(%d,%d)-(%d,%d) = %d (%c)\n",
1356 closure->piece,closure->ff,closure->rf,closure->ft,closure->rt,closure->promoChar,
1357 closure->promoChar >= ' ' ? closure->promoChar:'-');
1371 } CoordsToAlgebraicClosure;
1373 extern void CoordsToAlgebraicCallback P((Board board, int flags,
1374 ChessMove kind, int rf, int ff,
1375 int rt, int ft, VOIDSTAR closure));
1377 void CoordsToAlgebraicCallback(board, flags, kind, rf, ff, rt, ft, closure)
1384 register CoordsToAlgebraicClosure *cl =
1385 (CoordsToAlgebraicClosure *) closure;
1387 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
1388 (board[rf][ff] == cl->piece
1389 || PieceToChar(board[rf][ff]) == '~' &&
1390 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
1394 cl->kind = kind; /* this is the move we want */
1396 cl->file++; /* need file to rule out this move */
1400 cl->rank++; /* need rank to rule out this move */
1402 cl->either++; /* rank or file will rule out this move */
1408 /* Convert coordinates to normal algebraic notation.
1409 promoChar must be NULLCHAR or 'x' if not a promotion.
1411 ChessMove CoordsToAlgebraic(board, flags, rf, ff, rt, ft, promoChar, out)
1420 char *outp = out, c;
1421 CoordsToAlgebraicClosure cl;
1423 if (rf == DROP_RANK) {
1424 /* Bughouse piece drop */
1425 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
1430 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1432 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
1435 if (promoChar == 'x') promoChar = NULLCHAR;
1436 piece = board[rf][ff];
1437 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
1439 if (appData.debugMode)
1440 fprintf(debugFP, "CoordsToAlgebraic, piece=%d (%d,%d)-(%d,%d) %c\n", (int)piece,ff,rf,ft,rt,promoChar >= ' ' ? promoChar : '-');
1444 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1445 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1446 /* Keep short notation if move is illegal only because it
1447 leaves the player in check, but still return IllegalMove */
1448 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
1449 if (kind == IllegalMove) break;
1454 if (ff == ft && board[rt][ft] == EmptySquare) { /* [HGM] Xiangqi has straight noncapts! */
1455 /* Non-capture; use style "e5" */
1458 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1460 /* Capture; use style "exd5" */
1461 if(gameInfo.variant != VariantXiangqi || board[rt][ft] != EmptySquare )
1462 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
1466 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1468 /* Use promotion suffix style "=Q" */
1470 if (appData.debugMode)
1471 fprintf(debugFP, "movetype=%d, promochar=%d=%c\n", (int)kind, promoChar, promoChar >= ' ' ? promoChar : '-');
1472 if (promoChar != NULLCHAR) {
1473 if(gameInfo.variant == VariantShogi) {
1474 /* [HGM] ... but not in Shogi! */
1475 *outp++ = promoChar == '=' ? '=' : '+';
1478 *outp++ = ToUpper(promoChar);
1487 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
1488 /* Code added by Tord: FRC castling. */
1489 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
1490 (piece == BlackKing && board[rt][ft] == BlackRook)) {
1492 safeStrCpy(out, "O-O", MOVE_LEN);
1494 safeStrCpy(out, "O-O-O", MOVE_LEN);
1495 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1497 /* End of code added by Tord */
1498 /* Test for castling or ICS wild castling */
1499 /* Use style "O-O" (oh-oh) for PGN compatibility */
1500 else if (rf == rt &&
1501 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
1502 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
1503 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
1504 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
1505 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
1506 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1508 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
1510 /* This notation is always unambiguous, unless there are
1511 kings on both the d and e files, with "wild castling"
1512 possible for the king on the d file and normal castling
1513 possible for the other. ICS rules for wild 9
1514 effectively make castling illegal for either king in
1515 this situation. So I am not going to worry about it;
1516 I'll just generate an ambiguous O-O in this case.
1518 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
1521 /* else fall through */
1529 cl.kind = IllegalMove;
1530 cl.rank = cl.file = cl.either = 0;
1531 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1533 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
1534 /* Generate pretty moves for moving into check, but
1535 still return IllegalMove.
1537 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl);
1538 if (cl.kind == IllegalMove) break;
1539 cl.kind = IllegalMove;
1542 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
1543 else "Ngf3" or "Ngxf7",
1544 else "N1f3" or "N5xf7",
1545 else "Ng1f3" or "Ng5xf7".
1547 c = PieceToChar(piece) ;
1548 if( c == '~' || c == '+') {
1549 /* [HGM] print nonexistent piece as its demoted version */
1550 piece = (ChessSquare) (DEMOTED piece);
1552 if(c=='+') *outp++ = c;
1553 *outp++ = ToUpper(PieceToChar(piece));
1555 if (cl.file || (cl.either && !cl.rank)) {
1561 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1564 if(board[rt][ft] != EmptySquare)
1570 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1571 if (gameInfo.variant == VariantShogi) {
1572 /* [HGM] in Shogi non-pawns can promote */
1573 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
1575 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
1577 *outp++ = ToUpper(promoChar);
1583 /* Moving a nonexistent piece */
1587 /* Not a legal move, even ignoring check.
1588 If there was a piece on the from square,
1589 use style "Ng1g3" or "Ng1xe8";
1590 if there was a pawn or nothing (!),
1591 use style "g1g3" or "g1xe8". Use "x"
1592 if a piece was on the to square, even
1593 a piece of the same color.
1597 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
1599 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
1600 c += (board[r][f] == piece); // count on-board pieces of given type
1601 *outp++ = ToUpper(PieceToChar(piece));
1603 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
1607 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
1609 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
1613 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
1614 /* Use promotion suffix style "=Q" */
1615 if (promoChar != NULLCHAR && promoChar != 'x') {
1617 *outp++ = ToUpper(promoChar);
1624 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
1633 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
1635 int preyStackPointer, chaseStackPointer;
1638 char rf, ff, rt, ft;
1648 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
1650 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
1651 int rf, int ff, int rt, int ft,
1654 void AttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1660 { // For adding captures that can lead to chase indictment to the chaseStack
1661 if(board[rt][ft] == EmptySquare) return; // non-capture
1662 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
1663 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
1664 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
1665 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
1666 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
1667 chaseStack[chaseStackPointer].rf = rf;
1668 chaseStack[chaseStackPointer].ff = ff;
1669 chaseStack[chaseStackPointer].rt = rt;
1670 chaseStack[chaseStackPointer].ft = ft;
1671 chaseStackPointer++;
1674 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
1675 int rf, int ff, int rt, int ft,
1678 void ExistingAttacksCallback(board, flags, kind, rf, ff, rt, ft, closure)
1684 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
1686 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
1688 if(board[rt][ft] == EmptySquare) return; // no capture
1689 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
1690 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
1692 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
1693 for(i=0; i<chaseStackPointer; i++) {
1694 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
1695 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
1696 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
1697 chaseStack[i] = chaseStack[--chaseStackPointer];
1703 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
1704 int rf, int ff, int rt, int ft,
1707 void ProtectedCallback(board, flags, kind, rf, ff, rt, ft, closure)
1713 { // for determining if a piece (given through the closure) is protected
1714 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
1716 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
1717 if(appData.debugMode && board[rt][ft] != EmptySquare)
1718 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
1721 extern char moveList[MAX_MOVES][MOVE_LEN];
1723 int PerpetualChase(int first, int last)
1724 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
1727 ChessSquare captured;
1729 preyStackPointer = 0; // clear stack of chased pieces
1730 for(i=first; i<last; i+=2) { // for all positions with same side to move
1731 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
1732 chaseStackPointer = 0; // clear stack that is going to hold possible chases
1733 // determine all captures possible after the move, and put them on chaseStack
1734 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl);
1735 if(appData.debugMode) { int n;
1736 for(n=0; n<chaseStackPointer; n++)
1737 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1738 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1739 fprintf(debugFP, ": all capts\n");
1741 // determine all captures possible before the move, and delete them from chaseStack
1742 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
1743 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
1744 cl.rt = moveList[i][3]-ONE;
1745 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
1746 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl);
1747 if(appData.debugMode) { int n;
1748 for(n=0; n<chaseStackPointer; n++)
1749 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1750 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1751 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
1753 // chaseSack now contains all captures made possible by the move
1754 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
1755 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1756 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1758 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
1759 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
1761 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
1762 continue; // C or H attack on R is always chase; leave on chaseStack
1764 if(attacker == victim) {
1765 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
1766 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
1767 // we can capture back with equal piece, so this is no chase but a sacrifice
1768 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
1769 j--; /* ! */ continue;
1774 // the attack is on a lower piece, or on a pinned or blocked equal one
1775 // test if the victim is protected by a true protector. First make the capture.
1776 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1777 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
1778 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
1779 // Then test if the opponent can recapture
1780 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
1781 cl.rt = chaseStack[j].rt;
1782 cl.ft = chaseStack[j].ft;
1783 if(appData.debugMode) {
1784 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
1786 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl); // try all moves
1787 // unmake the capture
1788 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
1789 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
1790 // if a recapture was found, piece is protected, and we are not chasing it.
1791 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
1792 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
1796 // chaseStack now contains all moves that chased
1797 if(appData.debugMode) { int n;
1798 for(n=0; n<chaseStackPointer; n++)
1799 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
1800 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
1801 fprintf(debugFP, ": chases\n");
1803 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
1804 for(j=0; j<chaseStackPointer; j++) {
1805 preyStack[j].rank = chaseStack[j].rt;
1806 preyStack[j].file = chaseStack[j].ft;
1808 preyStackPointer = chaseStackPointer;
1811 for(j=0; j<chaseStackPointer; j++) {
1812 for(k=0; k<preyStackPointer; k++) {
1813 // search the victim of each chase move on the preyStack (first occurrence)
1814 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
1815 if(k < tail) break; // piece was already identified as still being chased
1816 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
1817 preyStack[tail] = preyStack[k]; // by swapping
1818 preyStack[k] = preyStack[preyStackPointer];
1824 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
1825 if(appData.debugMode) { int n;
1826 for(n=0; n<preyStackPointer; n++)
1827 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
1828 fprintf(debugFP, "always chased upto ply %d\n", i);
1830 // now adjust the location of the chased pieces according to opponent move
1831 for(j=0; j<preyStackPointer; j++) {
1832 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
1833 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
1834 preyStack[j].rank = moveList[i+1][3]-ONE;
1835 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
1840 return preyStackPointer; // if any piece was left on preyStack, it has been perpetually chased