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, 2013, 2014 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
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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
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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. */
61 #else /* not HAVE_STRING_H */
63 #endif /* not HAVE_STRING_H */
69 int WhitePiece P((ChessSquare));
70 int BlackPiece P((ChessSquare));
71 int SameColor P((ChessSquare, ChessSquare));
72 int PosFlags(int index);
74 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
76 char *pieceDesc[EmptySquare];
77 char *defaultDesc[EmptySquare] = {
78 "fmWfceFifmnD", "N", "B", "R", "Q",
79 "F", "A", "BN", "RN", "W", "K",
80 "mRcpR", "N0", "BW", "RF", "gQ",
81 "", "", "QN", "", "N", "",
83 "", "", "", "", "", "",
85 "", "", "", "", "", "K"
89 WhitePiece (ChessSquare piece)
91 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
95 BlackPiece (ChessSquare piece)
97 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
102 SameColor (ChessSquare piece1, ChessSquare piece2)
104 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
105 (int) piece1 < (int) BlackPawn &&
106 (int) piece2 >= (int) WhitePawn &&
107 (int) piece2 < (int) BlackPawn)
108 || ((int) piece1 >= (int) BlackPawn &&
109 (int) piece1 < (int) EmptySquare &&
110 (int) piece2 >= (int) BlackPawn &&
111 (int) piece2 < (int) EmptySquare);
114 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
117 char pieceToChar[] = {
118 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
119 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
120 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
121 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
123 char pieceNickName[EmptySquare];
126 PieceToChar (ChessSquare p)
128 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
129 return pieceToChar[(int) p];
133 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
136 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
138 while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
146 if(c == '.') return EmptySquare;
147 for(i=0; i< (int) EmptySquare; i++)
148 if(pieceNickName[i] == c) return (ChessSquare) i;
149 for(i=0; i< (int) EmptySquare; i++)
150 if(pieceToChar[i] == c) return (ChessSquare) i;
155 CopyBoard (Board to, Board from)
159 for (i = 0; i < BOARD_HEIGHT; i++)
160 for (j = 0; j < BOARD_WIDTH; j++)
161 to[i][j] = from[i][j];
162 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
163 to[VIRGIN][j] = from[VIRGIN][j],
164 to[CASTLING][j] = from[CASTLING][j];
165 to[HOLDINGS_SET] = 0; // flag used in ICS play
169 CompareBoards (Board board1, Board board2)
173 for (i = 0; i < BOARD_HEIGHT; i++)
174 for (j = 0; j < BOARD_WIDTH; j++) {
175 if (board1[i][j] != board2[i][j])
181 char defaultName[] = "PNBRQ......................................K" // white
182 "pnbrq......................................k"; // black
183 char shogiName[] = "PNBRLS...G.++++++..........................K" // white
184 "pnbrls...g.++++++..........................k"; // black
185 char xqName[] = "PH.R.AE..K.C................................" // white
186 "ph.r.ae..k.c................................"; // black
189 CollectPieceDescriptors ()
190 { // make a line of piece descriptions for use in the PGN Piece tag:
191 // dump all engine defined pieces, and pieces with non-standard names,
192 // but suppress black pieces that are the same as their white counterpart
194 static char buf[MSG_SIZ];
195 char *m, c, d, *pieceName = defaultName;
198 if(!pieceDefs) return "";
199 if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
200 if(gameInfo.variant == VariantShogi) pieceName = shogiName;
201 if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
202 for(p=WhitePawn; p<EmptySquare; p++) {
203 if((c = pieceToChar[p]) == '.' || c == '~') continue; // does not participate
204 m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED p] : c);
205 if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == toupper(c)
206 && (c != '+' || pieceToChar[DEMOTED BLACK_TO_WHITE p] == d)) { // black member of normal pair
207 char *wm = pieceDesc[BLACK_TO_WHITE p];
208 if(!m && !wm || m && wm && !strcmp(wm, m)) continue; // moves as a white piece
209 } else // white or unpaired black
210 if((p < BlackPawn || CharToPiece(toupper(d)) != EmptySquare) && // white or lone black
211 !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
212 // TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
213 if(!m) m = defaultDesc[p];
215 snprintf(buf+len, MSG_SIZ-len, "%s%s%c:%s", len ? ";" : "", c == '+' ? "+" : "", d, m);
220 // [HGM] gen: configurable move generation from Betza notation sent by engine.
221 // Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
222 // square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
223 // if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
224 // target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
225 // is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
226 // user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
227 // generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
228 // can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
229 // 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
233 // alphabet "abcdefghijklmnopqrstuvwxyz"
234 char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
235 char xStep[] = "2110.130.102.10.00....0..2";
236 char yStep[] = "2132.133.313.20.11....1..3";
237 char dirType[] = "01000104000200000260050000";
238 char upgrade[] = "AFCD.BGH.JQL.NO.KW....R..Z";
239 char rotate[] = "DRCA.WHG.JKL.NO.QB....F..Z";
241 // alphabet "a b c d e f g h i j k l m n o p q r s t u v w x y z "
242 int dirs1[] = { 0,0x3C,0,0,0,0xC3,0,0, 0,0,0,0xF0,0,0,0,0,0,0x0F,0 ,0,0,0 ,0,0,0,0 };
243 int dirs2[] = { 0,0x18,0,0,0,0x81,0,0xFF,0,0,0,0x60,0,0,0,0,0,0x06,0x66,0,0,0x99,0,0,0,0 };
244 int dirs3[] = { 0,0x38,0,0,0,0x83,0,0xFF,0,0,0,0xE0,0,0,0,0,0,0x0E,0xEE,0,0,0xBB,0,0,0,0 };
245 int dirs4[] = { 0,0x10,0,0,0,0x01,0,0xFF,0,0,0,0x40,0,0,0,0,0,0x04,0x44,0,0,0x11,0,0,0,0 };
247 int rot[][4] = { // rotation matrices for each direction
259 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
265 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
267 char buf[80], *p = desc, *atom = NULL;
268 int mine, his, dir, bit, occup, i, ep, promoRank = -1;
269 ChessMove promo= NormalMove; ChessSquare pc = board[r][f];
270 if(pc == DarkSquare) return; // this is not a piece, but a 'hole' in the board
271 if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
272 if(pc == WhitePawn || pc == WhiteLance) promo = WhitePromotion, promoRank = BOARD_HEIGHT-1; else
273 if(pc == BlackPawn || pc == BlackLance) promo = BlackPromotion, promoRank = 0;
274 while(*p) { // more moves to go
275 int expo = 1, dx, dy, x, y, mode, dirSet, ds2=0, retry=0, initial=0, jump=1, skip = 0, all = 0;
277 if(*p == 'i') initial = 1, desc = ++p;
278 while(islower(*p)) p++; // skip prefixes
279 if(!isupper(*p)) return; // syntax error: no atom
280 dx = xStep[*p-'A'] - '0';// step vector of atom
281 dy = yStep[*p-'A'] - '0';
282 dirSet = 0; // build direction set based on atom symmetry
283 switch(symmetry[*p-'A']) {
284 case 'B': expo = 0; // bishop, slide
285 case 'F': all = 0xAA; // diagonal atom (degenerate 4-fold)
286 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
287 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
288 int b = dirs1[*desc-'a']; // use wide version
289 if( islower(desc[1]) &&
290 ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim)
291 b = dirs1[*desc-'a'] & dirs1[desc[1]-'a']; // intersect wide & perp wide
296 dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
298 case 'R': expo = 0; // rook, slide
299 case 'W': all = 0x55; // orthogonal atom (non-deg 4-fold)
300 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
301 while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
302 dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
303 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
305 case 'N': all = 0xFF; // oblique atom (degenerate 8-fold)
306 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
307 if(*desc == 'h') { // chiral direction sets 'hr' and 'hl'
308 dirSet = (desc[1] == 'r' ? 0x55 : 0xAA); desc += 2;
310 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
311 int b = dirs2[*desc-'a']; // when alone, use narrow version
312 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
313 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
314 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
315 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
320 if(!dirSet) dirSet = 0xFF;
322 case 'Q': expo = 0; // queen, slide
323 case 'K': all = 0xFF; // non-deg (pseudo) 8-fold
325 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
326 int b = dirs4[*desc-'a']; // when alone, use narrow version
327 if(desc[1] == *desc) desc++; // doubling forces alone
328 else if(islower(desc[1]) && i < '4'
329 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
330 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
335 if(!dirSet) dirSet = (tx < 0 ? 0xFF // default is all directions, but in continuation leg
336 : all == 0xFF ? 0xEF : 0x45); // omits backward, and for 4-fold atoms also diags
337 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
338 ds2 = dirSet & 0xAA; // extract diagonal directions
339 if(dirSet &= 0x55) // start with orthogonal moves, if present
340 retry = 1, dx = 0; // and schedule the diagonal moves for later
341 else dx = dy, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
342 break; // should not have direction indicators
343 default: return; // syntax error: invalid atom
345 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
346 mode = 0; // build mode mask
347 if(*desc == 'm') mode |= 4, desc++; // move to empty
348 if(*desc == 'c') mode |= his, desc++; // capture foe
349 if(*desc == 'd') mode |= mine, desc++; // destroy (capture friend)
350 if(*desc == 'e') mode |= 8, desc++; // e.p. capture last mover
351 if(*desc == 't') mode |= 16, desc++; // exclude enemies as hop platform ('test')
352 if(*desc == 'p') mode |= 32, desc++; // hop over occupied
353 if(*desc == 'g') mode |= 64, desc++; // hop and toggle range
354 if(*desc == 'o') mode |= 128, desc++; // wrap around cylinder board
355 if(*desc == 'y') mode |= 512, desc++; // toggle range on empty square
356 if(*desc == 'n') jump = 0, desc++; // non-jumping
357 while(*desc == 'j') jump++, desc++; // must jump (on B,R,Q: skip first square)
358 if(*desc == 'a') cont = ++desc; // move again after doing what preceded it
359 if(isdigit(*++p)) expo = atoi(p++); // read exponent
360 if(expo > 9) p++; // allow double-digit
361 desc = p; // this is start of next move
362 if(initial && (board[r][f] != initialPosition[r][f] ||
363 r == 0 && board[TOUCHED_W] & 1<<f ||
364 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
365 if(expo > 1 && dx == 0 && dy == 0) { // castling indicated by O + number
366 mode |= 1024; dy = 1;
369 if(!(mode & 15)) mode |= his + 4; // no mode spec, use default = mc
371 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
372 atom = buf; while(islower(*atom)) atom++; // skip to atom
373 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
374 if(mode & 64 + 512) {
375 mode |= 256; // and 'g' too, but converts leaper <-> slider
376 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
377 *atom = upgrade[*atom-'A']; // replace atom, BRQ <-> FWK
378 atom[1] = atom[2] = '\0'; // make sure any old range is stripped off
379 if(expo == 1) atom[1] = '0'; // turn other leapers into riders
381 if(!(mode & 0x30F)) mode |= 4; // and default of this leg = m
383 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
385 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
386 int i = expo, j = skip, hop = mode, vx, vy, loop = 0;
387 if(!(bit & dirSet)) continue; // does not move in this direction
388 if(dy != 1) j = 0; //
389 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
390 vy = dx*rot[dir][2] + dy*rot[dir][3];
391 if(tx < 0) x = f, y = r; // start square
392 else x = tx, y = ty; // from previous to-square if continuation
394 x += vx; y += vy; // step to next square
395 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
396 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT, loop++; else break; }
397 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT, loop++; else break; }
398 if(board[y][x] == DarkSquare) break; // black squares are supposed to be off board
399 if(j) { j--; continue; } // skip irrespective of occupation
400 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
401 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
402 if(x == f && y == r && !loop) occup = 4; else // start square counts as empty (if not around cylinder!)
403 if(board[y][x] < BlackPawn) occup = 0x101; else
404 if(board[y][x] < EmptySquare) occup = 0x102; else
406 if(cont) { // non-final leg
407 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
408 if(occup & mode) { // valid intermediate square, do continuation
409 char origAtom = *atom;
410 if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
411 if(occup & mode & 0x104) // no side effects, merge legs to one move
412 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
413 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
415 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
416 if(cnt) { // and if there are
417 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
419 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
423 *atom = origAtom; // undo any interconversion
425 if(occup != 4) break; // occupied squares always terminate the leg
428 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
430 if(mode & 8 && occup == 4 && board[EP_FILE] == x && (y == (ep & 127) || y - vy == ep - 128)) { // to e.p. square (or 2nd e.p. square)
431 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
433 if(mode & 1024) { // castling
434 i = 2; // kludge to elongate move indefinitely
435 if(occup == 4) continue; // skip empty squares
436 if((x == BOARD_LEFT || vx < 0 && board[y][x-1] == DarkSquare) && board[y][x] == initialPosition[y][x]) { // reached initial corner piece
437 if(pc != WhiteKing && pc != BlackKing) { // non-royal castling (to be entered as two-leg move via 'Rook')
438 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); if(killX < f)
439 legNr <<= 1, cb(board, flags, NormalMove, r, f, y, f - expo, cl), legNr >>= 1;
441 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
443 if((x == BOARD_RGHT-1 || vx > 0 && board[y][x+1] == DarkSquare) && board[y][x] == initialPosition[y][x]) {
444 if(pc != WhiteKing && pc != BlackKing) {
445 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); if(killX > f)
446 legNr <<= 1, cb(board, flags, NormalMove, r, f, y, f + expo, cl), legNr >>= 1;
448 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
452 if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
453 if(occup & mode) cb(board, flags, y == promoRank ? promo : NormalMove, r, f, y, x, cl); // allowed, generate
454 if(occup != 4) break; // not valid transit square
457 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
458 } while(retry-- && ds2); // and start doing them
459 if(tx >= 0) break; // don't do other atoms in continuation legs
463 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
466 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
471 if (rt >= BOARD_HEIGHT) break;
472 if (SameColor(board[rf][ff], board[rt][ft])) break;
473 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
474 if (board[rt][ft] != EmptySquare) break;
479 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
485 if (SameColor(board[rf][ff], board[rt][ft])) break;
486 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
487 if (board[rt][ft] != EmptySquare) break;
492 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
494 SlideForward(board, flags, rf, ff, callback, closure);
495 SlideBackward(board, flags, rf, ff, callback, closure);
499 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
501 int i, s, rt = rf, ft;
502 for(s = -1; s <= 1; s+= 2) {
505 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
506 if (SameColor(board[rf][ff], board[rt][ft])) break;
507 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
508 if (board[rt][ft] != EmptySquare) break;
514 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
517 for(s = -1; s <= 1; s+= 2) {
521 if (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, rf, ff, rt, ft, closure);
524 if (board[rt][ft] != EmptySquare) break;
530 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
533 for(s = -1; s <= 1; s+= 2) {
537 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
538 if (SameColor(board[rf][ff], board[rt][ft])) break;
539 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
540 if (board[rt][ft] != EmptySquare) break;
546 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
548 SlideVertical(board, flags, rf, ff, callback, closure);
549 SlideSideways(board, flags, rf, ff, callback, closure);
553 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
555 SlideDiagForward(board, flags, rf, ff, callback, closure);
556 SlideDiagBackward(board, flags, rf, ff, callback, closure);
560 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
561 { // Lion-like move of Horned Falcon and Souring Eagle
562 int ft = ff + dx, rt = rf + dy;
563 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
565 if (!SameColor(board[rf][ff], board[rt][ft]))
566 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
569 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
571 if (!SameColor(board[rf][ff], board[rt][ft]))
572 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
573 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
574 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
579 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
581 int ft = ff, rt = rf + 1;
582 if (rt >= BOARD_HEIGHT) return;
583 if (SameColor(board[rf][ff], board[rt][ft])) return;
584 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
588 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
590 int ft = ff, rt = rf - 1;
592 if (SameColor(board[rf][ff], board[rt][ft])) return;
593 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
597 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
601 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
602 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
604 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
605 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
609 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
612 if (rt >= BOARD_HEIGHT) return;
614 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
615 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
617 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
618 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
622 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
627 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
628 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
630 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
631 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
635 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
637 StepForward(board, flags, rf, ff, callback, closure);
638 StepBackward(board, flags, rf, ff, callback, closure);
642 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
644 StepDiagForward(board, flags, rf, ff, callback, closure);
645 StepDiagBackward(board, flags, rf, ff, callback, closure);
649 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
651 StepVertical(board, flags, rf, ff, callback, closure);
652 StepSideways(board, flags, rf, ff, callback, closure);
656 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
659 for (i = -1; i <= 1; i += 2)
660 for (j = -1; j <= 1; j += 2)
661 for (s = 1; s <= 2; s++) {
664 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
665 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
666 && !SameColor(board[rf][ff], board[rt][ft]))
667 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
671 /* Call callback once for each pseudo-legal move in the given
672 position, except castling moves. A move is pseudo-legal if it is
673 legal, or if it would be legal except that it leaves the king in
674 check. In the arguments, epfile is EP_NONE if the previous move
675 was not a double pawn push, or the file 0..7 if it was, or
676 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
677 Promotion moves generated are to Queen only.
680 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
681 // speed: only do moves with this piece type
684 int i, j, d, s, fs, rs, rt, ft, m;
685 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
686 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
688 for (rf = 0; rf < BOARD_HEIGHT; rf++)
689 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
692 if(board[rf][ff] == EmptySquare) continue;
693 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
694 m = 0; piece = board[rf][ff];
695 if(PieceToChar(piece) == '~')
696 piece = (ChessSquare) ( DEMOTED piece );
697 if(filter != EmptySquare && piece != filter) continue;
698 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
699 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
702 if(IS_SHOGI(gameInfo.variant))
703 piece = (ChessSquare) ( SHOGI piece );
705 switch ((int)piece) {
706 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
708 /* can't happen ([HGM] except for faries...) */
712 if(gameInfo.variant == VariantXiangqi) {
713 /* [HGM] capture and move straight ahead in Xiangqi */
714 if (rf < BOARD_HEIGHT-1 &&
715 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
716 callback(board, flags, NormalMove,
717 rf, ff, rf + 1, ff, closure);
719 /* and move sideways when across the river */
720 for (s = -1; s <= 1; s += 2) {
721 if (rf >= BOARD_HEIGHT>>1 &&
722 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
723 !WhitePiece(board[rf][ff+s]) ) {
724 callback(board, flags, NormalMove,
725 rf, ff, rf, ff+s, closure);
730 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
731 callback(board, flags,
732 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
733 rf, ff, rf + 1, ff, closure);
735 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
736 gameInfo.variant != VariantShatranj && /* [HGM] */
737 gameInfo.variant != VariantCourier && /* [HGM] */
738 board[rf+2][ff] == EmptySquare ) {
739 callback(board, flags, NormalMove,
740 rf, ff, rf+2, ff, closure);
742 for (s = -1; s <= 1; s += 2) {
743 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
744 ((flags & F_KRIEGSPIEL_CAPTURE) ||
745 BlackPiece(board[rf + 1][ff + s]))) {
746 callback(board, flags,
747 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
748 rf, ff, rf + 1, ff + s, closure);
750 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
751 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
752 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
753 board[rf][ff + s] == BlackPawn &&
754 board[rf+1][ff + s] == EmptySquare) {
755 callback(board, flags, WhiteCapturesEnPassant,
756 rf, ff, rf+1, ff + s, closure);
763 if(gameInfo.variant == VariantXiangqi) {
764 /* [HGM] capture straight ahead in Xiangqi */
765 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
766 callback(board, flags, NormalMove,
767 rf, ff, rf - 1, ff, closure);
769 /* and move sideways when across the river */
770 for (s = -1; s <= 1; s += 2) {
771 if (rf < BOARD_HEIGHT>>1 &&
772 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
773 !BlackPiece(board[rf][ff+s]) ) {
774 callback(board, flags, NormalMove,
775 rf, ff, rf, ff+s, closure);
780 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
781 callback(board, flags,
782 rf <= promoRank ? BlackPromotion : NormalMove,
783 rf, ff, rf - 1, ff, closure);
785 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
786 gameInfo.variant != VariantShatranj && /* [HGM] */
787 gameInfo.variant != VariantCourier && /* [HGM] */
788 board[rf-2][ff] == EmptySquare) {
789 callback(board, flags, NormalMove,
790 rf, ff, rf-2, ff, closure);
792 for (s = -1; s <= 1; s += 2) {
793 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
794 ((flags & F_KRIEGSPIEL_CAPTURE) ||
795 WhitePiece(board[rf - 1][ff + s]))) {
796 callback(board, flags,
797 rf <= promoRank ? BlackPromotion : NormalMove,
798 rf, ff, rf - 1, ff + s, closure);
800 if (rf < BOARD_HEIGHT>>1) {
801 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
802 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
803 board[rf][ff + s] == WhitePawn &&
804 board[rf-1][ff + s] == EmptySquare) {
805 callback(board, flags, BlackCapturesEnPassant,
806 rf, ff, rf-1, ff + s, closure);
816 for (i = -1; i <= 1; i += 2)
817 for (j = -1; j <= 1; j += 2)
818 for (s = 1; s <= 2; s++) {
821 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
822 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
823 && !SameColor(board[rf][ff], board[rt][ft]))
824 callback(board, flags, NormalMove,
825 rf, ff, rt, ft, closure);
829 case SHOGI WhiteKnight:
830 for (s = -1; s <= 1; s += 2) {
831 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
832 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
833 callback(board, flags, NormalMove,
834 rf, ff, rf + 2, ff + s, closure);
839 case SHOGI BlackKnight:
840 for (s = -1; s <= 1; s += 2) {
841 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
842 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
843 callback(board, flags, NormalMove,
844 rf, ff, rf - 2, ff + s, closure);
851 for (d = 0; d <= 1; d++)
852 for (s = -1; s <= 1; s += 2) {
855 rt = rf + (i * s) * d;
856 ft = ff + (i * s) * (1 - d);
857 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
858 if (m == 0 && board[rt][ft] == EmptySquare)
859 callback(board, flags, NormalMove,
860 rf, ff, rt, ft, closure);
861 if (m == 1 && board[rt][ft] != EmptySquare &&
862 !SameColor(board[rf][ff], board[rt][ft]) )
863 callback(board, flags, NormalMove,
864 rf, ff, rt, ft, closure);
865 if (board[rt][ft] != EmptySquare && m++) break;
870 /* Gold General (and all its promoted versions) . First do the */
871 /* diagonal forward steps, then proceed as normal Wazir */
872 case SHOGI (PROMOTED WhitePawn):
873 if(gameInfo.variant == VariantShogi) goto WhiteGold;
874 case SHOGI (PROMOTED BlackPawn):
875 if(gameInfo.variant == VariantShogi) goto BlackGold;
876 SlideVertical(board, flags, rf, ff, callback, closure);
879 case SHOGI (PROMOTED WhiteKnight):
880 if(gameInfo.variant == VariantShogi) goto WhiteGold;
881 case SHOGI BlackDrunk:
882 case SHOGI BlackAlfil:
883 Ferz(board, flags, rf, ff, callback, closure);
884 StepSideways(board, flags, rf, ff, callback, closure);
885 StepBackward(board, flags, rf, ff, callback, closure);
888 case SHOGI (PROMOTED BlackKnight):
889 if(gameInfo.variant == VariantShogi) goto BlackGold;
890 case SHOGI WhiteDrunk:
891 case SHOGI WhiteAlfil:
892 Ferz(board, flags, rf, ff, callback, closure);
893 StepSideways(board, flags, rf, ff, callback, closure);
894 StepForward(board, flags, rf, ff, callback, closure);
898 case SHOGI WhiteStag:
899 case SHOGI BlackStag:
900 if(gameInfo.variant == VariantShogi) goto BlackGold;
901 SlideVertical(board, flags, rf, ff, callback, closure);
902 Ferz(board, flags, rf, ff, callback, closure);
903 StepSideways(board, flags, rf, ff, callback, closure);
906 case SHOGI (PROMOTED WhiteQueen):
907 case SHOGI WhiteTokin:
908 case SHOGI WhiteWazir:
910 StepDiagForward(board, flags, rf, ff, callback, closure);
911 Wazir(board, flags, rf, ff, callback, closure);
914 case SHOGI (PROMOTED BlackQueen):
915 case SHOGI BlackTokin:
916 case SHOGI BlackWazir:
918 StepDiagBackward(board, flags, rf, ff, callback, closure);
919 Wazir(board, flags, rf, ff, callback, closure);
924 Wazir(board, flags, rf, ff, callback, closure);
927 case SHOGI WhiteMarshall:
928 case SHOGI BlackMarshall:
929 Ferz(board, flags, rf, ff, callback, closure);
930 for (d = 0; d <= 1; d++)
931 for (s = -2; s <= 2; s += 4) {
933 ft = ff + s * (1 - d);
934 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
935 if (!SameColor(board[rf][ff], board[rt][ft]) )
936 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
940 case SHOGI WhiteAngel:
941 case SHOGI BlackAngel:
942 Wazir(board, flags, rf, ff, callback, closure);
946 /* [HGM] support Shatranj pieces */
947 for (rs = -1; rs <= 1; rs += 2)
948 for (fs = -1; fs <= 1; fs += 2) {
951 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
952 && ( gameInfo.variant != VariantXiangqi ||
953 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
955 && !SameColor(board[rf][ff], board[rt][ft]))
956 callback(board, flags, NormalMove,
957 rf, ff, rt, ft, closure);
958 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
959 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
960 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
962 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
963 && !SameColor(board[rf][ff], board[rt][ft]))
964 callback(board, flags, NormalMove,
965 rf, ff, rt, ft, closure);
967 if(gameInfo.variant == VariantSpartan)
968 for(fs = -1; fs <= 1; fs += 2) {
970 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
971 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
975 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
978 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
979 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
980 for (s = -2; s <= 2; s += 4) {
982 ft = ff + s * (1 - d);
983 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
984 if (SameColor(board[rf][ff], board[rt][ft])) continue;
985 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
988 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
989 case SHOGI WhiteCardinal:
990 case SHOGI BlackCardinal:
991 case SHOGI WhitePCardinal:
992 case SHOGI BlackPCardinal:
994 Bishop(board, flags, rf, ff, callback, closure);
995 Wazir(board, flags, rf, ff, callback, closure);
998 /* Capablanca Archbishop continues as Knight */
1001 Knight(board, flags, rf, ff, callback, closure);
1003 /* Shogi Bishops are ordinary Bishops */
1004 case SHOGI WhiteBishop:
1005 case SHOGI BlackBishop:
1006 case SHOGI WhitePBishop:
1007 case SHOGI BlackPBishop:
1010 Bishop(board, flags, rf, ff, callback, closure);
1013 /* Shogi Lance is unlike anything, and asymmetric at that */
1014 case SHOGI WhiteQueen:
1015 if(gameInfo.variant == VariantChu) goto doQueen;
1019 if (rt >= BOARD_HEIGHT) break;
1020 if (SameColor(board[rf][ff], board[rt][ft])) break;
1021 callback(board, flags, NormalMove,
1022 rf, ff, rt, ft, closure);
1023 if (board[rt][ft] != EmptySquare) break;
1027 case SHOGI BlackQueen:
1028 if(gameInfo.variant == VariantChu) goto doQueen;
1033 if (SameColor(board[rf][ff], board[rt][ft])) break;
1034 callback(board, flags, NormalMove,
1035 rf, ff, rt, ft, closure);
1036 if (board[rt][ft] != EmptySquare) break;
1040 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1043 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1044 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1045 for (s = -2; s <= 2; s += 4) {
1047 ft = ff + s * (1 - d);
1048 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1049 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1050 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1051 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1053 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1054 Wazir(board, flags, rf, ff, callback, closure);
1056 Rook(board, flags, rf, ff, callback, closure);
1059 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1060 case SHOGI WhiteDragon:
1061 case SHOGI BlackDragon:
1062 case SHOGI WhitePDragon:
1063 case SHOGI BlackPDragon:
1065 Rook(board, flags, rf, ff, callback, closure);
1066 Ferz(board, flags, rf, ff, callback, closure);
1070 /* Capablanca Chancellor sets flag to continue as Knight */
1073 Rook(board, flags, rf, ff, callback, closure);
1074 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1075 Ferz(board, flags, rf, ff, callback, closure);
1077 Knight(board, flags, rf, ff, callback, closure);
1080 /* Shogi Rooks are ordinary Rooks */
1081 case SHOGI WhiteRook:
1082 case SHOGI BlackRook:
1083 case SHOGI WhitePRook:
1084 case SHOGI BlackPRook:
1087 Rook(board, flags, rf, ff, callback, closure);
1092 case SHOGI WhiteMother:
1093 case SHOGI BlackMother:
1095 Rook(board, flags, rf, ff, callback, closure);
1096 Bishop(board, flags, rf, ff, callback, closure);
1099 case SHOGI WhitePawn:
1100 StepForward(board, flags, rf, ff, callback, closure);
1103 case SHOGI BlackPawn:
1104 StepBackward(board, flags, rf, ff, callback, closure);
1108 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1109 case SHOGI WhiteFerz:
1110 Ferz(board, flags, rf, ff, callback, closure);
1111 StepForward(board, flags, rf, ff, callback, closure);
1115 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1116 case SHOGI BlackFerz:
1117 StepBackward(board, flags, rf, ff, callback, closure);
1121 /* [HGM] support Shatranj pieces */
1122 Ferz(board, flags, rf, ff, callback, closure);
1127 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1130 case SHOGI WhiteMonarch:
1131 case SHOGI BlackMonarch:
1132 case SHOGI WhiteKing:
1133 case SHOGI BlackKing:
1136 Ferz(board, flags, rf, ff, callback, closure);
1137 Wazir(board, flags, rf, ff, callback, closure);
1140 case WhiteNightrider:
1141 case BlackNightrider:
1142 for (i = -1; i <= 1; i += 2)
1143 for (j = -1; j <= 1; j += 2)
1144 for (s = 1; s <= 2; s++) { int k;
1147 ft = ff + k*j*(3-s);
1148 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1149 if (SameColor(board[rf][ff], board[rt][ft])) break;
1150 callback(board, flags, NormalMove,
1151 rf, ff, rt, ft, closure);
1152 if (board[rt][ft] != EmptySquare) break;
1158 Bishop(board, flags, rf, ff, callback, closure);
1159 Rook(board, flags, rf, ff, callback, closure);
1160 Knight(board, flags, rf, ff, callback, closure);
1163 // Use Lance as Berolina / Spartan Pawn.
1165 if(gameInfo.variant == VariantSuper) goto Amazon;
1166 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1167 callback(board, flags,
1168 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1169 rf, ff, rf + 1, ff, closure);
1170 for (s = -1; s <= 1; s += 2) {
1171 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1172 callback(board, flags,
1173 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1174 rf, ff, rf + 1, ff + s, closure);
1175 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1176 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1181 if(gameInfo.variant == VariantSuper) goto Amazon;
1182 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1183 callback(board, flags,
1184 rf <= promoRank ? BlackPromotion : NormalMove,
1185 rf, ff, rf - 1, ff, closure);
1186 for (s = -1; s <= 1; s += 2) {
1187 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1188 callback(board, flags,
1189 rf <= promoRank ? BlackPromotion : NormalMove,
1190 rf, ff, rf - 1, ff + s, closure);
1191 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1192 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1196 case SHOGI WhiteNothing:
1197 case SHOGI BlackNothing:
1198 case SHOGI WhiteLion:
1199 case SHOGI BlackLion:
1202 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1203 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1204 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1205 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1206 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1207 rf, ff, rt, ft, closure);
1212 case SHOGI WhiteFalcon:
1213 case SHOGI BlackFalcon:
1214 case SHOGI WhitePDagger:
1215 case SHOGI BlackPDagger:
1216 SlideSideways(board, flags, rf, ff, callback, closure);
1217 StepVertical(board, flags, rf, ff, callback, closure);
1220 case SHOGI WhiteCobra:
1221 case SHOGI BlackCobra:
1222 StepVertical(board, flags, rf, ff, callback, closure);
1225 case SHOGI (PROMOTED WhiteFerz):
1226 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1227 case SHOGI (PROMOTED BlackFerz):
1228 if(gameInfo.variant == VariantShogi) goto BlackGold;
1229 case SHOGI WhitePSword:
1230 case SHOGI BlackPSword:
1231 SlideVertical(board, flags, rf, ff, callback, closure);
1232 StepSideways(board, flags, rf, ff, callback, closure);
1235 case SHOGI WhiteUnicorn:
1236 case SHOGI BlackUnicorn:
1237 Ferz(board, flags, rf, ff, callback, closure);
1238 StepVertical(board, flags, rf, ff, callback, closure);
1241 case SHOGI WhiteMan:
1242 StepDiagForward(board, flags, rf, ff, callback, closure);
1243 StepVertical(board, flags, rf, ff, callback, closure);
1246 case SHOGI BlackMan:
1247 StepDiagBackward(board, flags, rf, ff, callback, closure);
1248 StepVertical(board, flags, rf, ff, callback, closure);
1251 case SHOGI WhiteHCrown:
1252 case SHOGI BlackHCrown:
1253 Bishop(board, flags, rf, ff, callback, closure);
1254 SlideSideways(board, flags, rf, ff, callback, closure);
1257 case SHOGI WhiteCrown:
1258 case SHOGI BlackCrown:
1259 Bishop(board, flags, rf, ff, callback, closure);
1260 SlideVertical(board, flags, rf, ff, callback, closure);
1263 case SHOGI WhiteHorned:
1264 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1265 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1266 if(killX >= 0) break;
1267 Bishop(board, flags, rf, ff, callback, closure);
1268 SlideSideways(board, flags, rf, ff, callback, closure);
1269 SlideBackward(board, flags, rf, ff, callback, closure);
1272 case SHOGI BlackHorned:
1273 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1274 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1275 if(killX >= 0) break;
1276 Bishop(board, flags, rf, ff, callback, closure);
1277 SlideSideways(board, flags, rf, ff, callback, closure);
1278 SlideForward(board, flags, rf, ff, callback, closure);
1281 case SHOGI WhiteEagle:
1282 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1283 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1284 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1285 if(killX >= 0) break;
1286 Rook(board, flags, rf, ff, callback, closure);
1287 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1290 case SHOGI BlackEagle:
1291 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1292 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1293 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1294 if(killX >= 0) break;
1295 Rook(board, flags, rf, ff, callback, closure);
1296 SlideDiagForward(board, flags, rf, ff, callback, closure);
1299 case SHOGI WhiteDolphin:
1300 case SHOGI BlackHorse:
1301 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1302 SlideVertical(board, flags, rf, ff, callback, closure);
1305 case SHOGI BlackDolphin:
1306 case SHOGI WhiteHorse:
1307 SlideDiagForward(board, flags, rf, ff, callback, closure);
1308 SlideVertical(board, flags, rf, ff, callback, closure);
1311 case SHOGI WhiteLance:
1312 SlideForward(board, flags, rf, ff, callback, closure);
1315 case SHOGI BlackLance:
1316 SlideBackward(board, flags, rf, ff, callback, closure);
1319 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1323 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1336 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1337 Board xqCheckers, nullBoard;
1339 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1340 int rf, int ff, int rt, int ft,
1344 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1346 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1348 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1350 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1352 if (!(flags & F_IGNORE_CHECK) ) {
1353 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1356 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1357 kings += (board[r][f] == BlackKing);
1361 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1363 check = CheckTest(board, flags, rf, ff, rt, ft,
1364 kind == WhiteCapturesEnPassant ||
1365 kind == BlackCapturesEnPassant);
1366 if(promo) board[rf][ff] = BlackLance;
1369 if (flags & F_ATOMIC_CAPTURE) {
1370 if (board[rt][ft] != EmptySquare ||
1371 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1373 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1374 if (board[rf][ff] == king) return;
1375 for (r = rt-1; r <= rt+1; r++) {
1376 for (f = ft-1; f <= ft+1; f++) {
1377 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1378 board[r][f] == king) return;
1383 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1390 int captures; // [HGM] losers
1391 } LegalityTestClosure;
1394 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1395 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1396 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1397 moves that would destroy your own king. The CASTLE_OK flags are
1398 true if castling is not yet ruled out by a move of the king or
1399 rook. Return TRUE if the player on move is currently in check and
1400 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1402 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1405 int ff, ft, k, left, right, swap;
1406 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1407 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1408 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1413 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1414 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1415 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1417 if (inCheck) return TRUE;
1419 /* Generate castling moves */
1420 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1421 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1424 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1425 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1427 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1428 if ((flags & F_WHITE_ON_MOVE) &&
1429 (flags & F_WHITE_KCASTLE_OK) &&
1430 board[0][ff] == wKing &&
1431 board[0][ff + 1] == EmptySquare &&
1432 board[0][ff + 2] == EmptySquare &&
1433 board[0][BOARD_RGHT-3] == EmptySquare &&
1434 board[0][BOARD_RGHT-2] == EmptySquare &&
1435 board[0][BOARD_RGHT-1] == WhiteRook &&
1436 castlingRights[0] != NoRights && /* [HGM] check rights */
1437 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1439 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1440 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1441 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1442 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1444 callback(board, flags,
1445 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1446 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1448 if ((flags & F_WHITE_ON_MOVE) &&
1449 (flags & F_WHITE_QCASTLE_OK) &&
1450 board[0][ff] == wKing &&
1451 board[0][ff - 1] == EmptySquare &&
1452 board[0][ff - 2] == EmptySquare &&
1453 board[0][BOARD_LEFT+2] == EmptySquare &&
1454 board[0][BOARD_LEFT+1] == EmptySquare &&
1455 board[0][BOARD_LEFT+0] == WhiteRook &&
1456 castlingRights[1] != NoRights && /* [HGM] check rights */
1457 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1459 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1460 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1461 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1463 callback(board, flags,
1464 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1465 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1467 if (!(flags & F_WHITE_ON_MOVE) &&
1468 (flags & F_BLACK_KCASTLE_OK) &&
1469 board[BOARD_HEIGHT-1][ff] == bKing &&
1470 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1471 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1472 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1473 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1474 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1475 castlingRights[3] != NoRights && /* [HGM] check rights */
1476 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1478 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1479 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1480 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1481 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1483 callback(board, flags,
1484 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1485 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1487 if (!(flags & F_WHITE_ON_MOVE) &&
1488 (flags & F_BLACK_QCASTLE_OK) &&
1489 board[BOARD_HEIGHT-1][ff] == bKing &&
1490 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1491 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1492 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1493 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1494 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1495 castlingRights[4] != NoRights && /* [HGM] check rights */
1496 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1498 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1499 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1500 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1502 callback(board, flags,
1503 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1504 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1508 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1510 /* generate all potential FRC castling moves (KxR), ignoring flags */
1511 /* [HGM] test if the Rooks we find have castling rights */
1512 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1515 if ((flags & F_WHITE_ON_MOVE) != 0) {
1516 ff = castlingRights[2]; /* King file if we have any rights */
1517 if(ff != NoRights && board[0][ff] == WhiteKing) {
1518 if (appData.debugMode) {
1519 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1520 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1522 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1524 right = BOARD_RGHT-2;
1525 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1526 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1527 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1528 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1529 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1530 if(ft != NoRights && board[0][ft] == WhiteRook) {
1531 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1532 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1535 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1536 left = BOARD_LEFT+2;
1538 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1539 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1540 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1541 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1542 if(ff > BOARD_LEFT+2)
1543 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1544 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1545 if(ft != NoRights && board[0][ft] == WhiteRook) {
1546 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1547 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1551 ff = castlingRights[5]; /* King file if we have any rights */
1552 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1553 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1555 right = BOARD_RGHT-2;
1556 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1557 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1558 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1559 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1560 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1561 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1562 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1563 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1566 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1567 left = BOARD_LEFT+2;
1569 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1570 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1571 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1572 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1573 if(ff > BOARD_LEFT+2)
1574 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1575 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1576 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1577 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1578 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1595 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1596 int rf, int ff, int rt, int ft,
1601 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1603 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1605 if (rt == cl->rking && ft == cl->fking) {
1606 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1608 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1610 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1611 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1612 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1616 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1617 he leave himself in check? Or if rf == -1, is the player on move
1618 in check now? enPassant must be TRUE if the indicated move is an
1619 e.p. capture. The possibility of castling out of a check along the
1620 back rank is not accounted for (i.e., we still return nonzero), as
1621 this is illegal anyway. Return value is the number of times the
1622 king is in check. */
1624 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1626 CheckTestClosure cl;
1627 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1628 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1629 int saveKill = killX;
1630 /* Suppress warnings on uninitialized variables */
1632 if(gameInfo.variant == VariantXiangqi)
1633 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1634 if(gameInfo.variant == VariantKnightmate)
1635 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1636 if(gameInfo.variant == VariantChu || gameInfo.variant == VariantShogi) { // strictly speaking this is not needed, as Chu officially has no check
1637 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1638 if(gameInfo.variant == VariantShogi) prince -= 11; // White/BlackFalcon
1639 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1640 if(board[r][f] == k || board[r][f] == prince) {
1641 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1642 king = board[r][f]; // remember hich one we had
1649 captured = board[rf][ft];
1650 board[rf][ft] = EmptySquare;
1652 captured = board[rt][ft];
1653 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; }
1655 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1656 board[rt][ft] = board[rf][ff];
1657 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1659 ep = board[EP_STATUS];
1660 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1661 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1662 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1663 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1664 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1665 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1669 /* For compatibility with ICS wild 9, we scan the board in the
1670 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1671 and we test only whether that one is in check. */
1672 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1673 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1674 if (board[cl.rking][cl.fking] == king) {
1676 if(gameInfo.variant == VariantXiangqi) {
1677 /* [HGM] In Xiangqi opposing Kings means check as well */
1679 dir = (king >= BlackPawn) ? -1 : 1;
1680 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1681 board[i][cl.fking] == EmptySquare; i+=dir );
1682 if(i>=0 && i<BOARD_HEIGHT &&
1683 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1686 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1687 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1688 goto undo_move; /* 2-level break */
1695 if(rf != DROP_RANK) // [HGM] drop
1696 board[rf][ff] = board[rt][ft];
1698 board[rf][ft] = captured;
1699 board[rt][ft] = EmptySquare;
1701 if(saveKill >= 0) board[killY][killX = saveKill] = trampled;
1702 board[rt][ft] = captured;
1704 board[EP_STATUS] = ep;
1707 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1711 HasLion (Board board, int flags)
1713 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1715 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1716 if(board[r][f] == lion) return 1;
1721 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1722 { // [HGM] put drop legality testing in separate routine for clarity
1724 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1725 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1726 n = PieceToNumber(piece);
1727 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1728 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1729 return ImpossibleMove; // piece not available
1730 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1731 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1732 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1733 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1734 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1735 if(piece == WhitePawn || piece == BlackPawn) {
1736 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1737 for(r=1; r<BOARD_HEIGHT-1; r++)
1738 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1739 // should still test if we mate with this Pawn
1741 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1742 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1744 if( (piece == WhitePawn || piece == BlackPawn) &&
1745 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1746 return IllegalMove; /* no pawn drops on 1st/8th */
1748 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1749 if (!(flags & F_IGNORE_CHECK) &&
1750 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1751 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1754 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1755 int rf, int ff, int rt, int ft,
1759 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1761 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1763 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1764 cl->captures++; // [HGM] losers: count legal captures
1765 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1770 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1772 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1774 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1775 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1776 piece = filterPiece = board[rf][ff];
1777 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1779 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1780 /* (perhaps we should disallow moves that obviously leave us in check?) */
1781 if((piece == WhiteFalcon || piece == BlackFalcon ||
1782 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1783 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1787 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1788 cl.ft = fFilter = ft;
1789 cl.kind = IllegalMove;
1790 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1791 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1792 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1793 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1794 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1795 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1797 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1798 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1799 if(board[rf][ff] < BlackPawn) { // white
1800 if(rf != 0) return IllegalMove; // must be on back rank
1801 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1802 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1803 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1804 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1806 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1807 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1808 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1809 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1810 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1813 if(gameInfo.variant == VariantChu) {
1814 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1815 if(promoChar != '+')
1816 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1817 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1818 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1820 if(gameInfo.variant == VariantShogi) {
1821 /* [HGM] Shogi promotions. '=' means defer */
1822 if(rf != DROP_RANK && cl.kind == NormalMove) {
1823 ChessSquare piece = board[rf][ff];
1825 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1826 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1827 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1828 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1829 promoChar = '+'; // allowed ICS notations
1830 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1831 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1832 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1833 else if(flags & F_WHITE_ON_MOVE) {
1834 if( (int) piece < (int) WhiteWazir &&
1835 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1836 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1837 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1838 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1839 else /* promotion optional, default is defer */
1840 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1841 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1843 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1844 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1845 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1846 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1847 else /* promotion optional, default is defer */
1848 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1849 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1853 if (promoChar != NULLCHAR) {
1854 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1855 ChessSquare piece = board[rf][ff];
1856 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1857 // should test if in zone, really
1858 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1860 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1862 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1863 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1864 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1865 if(piece == EmptySquare)
1866 cl.kind = ImpossibleMove; // non-existing piece
1867 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1868 cl.kind = IllegalMove; // no two Lions
1869 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1870 if(promoChar != PieceToChar(BlackKing)) {
1871 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1872 if(piece == BlackLance) cl.kind = ImpossibleMove;
1873 } else { // promotion to King allowed only if we do not have two yet
1874 int r, f, kings = 0;
1875 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1876 if(kings == 2) cl.kind = IllegalMove;
1878 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1879 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1880 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1881 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1882 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1883 cl.kind = IllegalMove; // promotion to King usually not allowed
1885 cl.kind = IllegalMove;
1895 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1896 int rf, int ff, int rt, int ft,
1900 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1902 register MateTestClosure *cl = (MateTestClosure *) closure;
1907 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1909 MateTest (Board board, int flags)
1912 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1913 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1915 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1916 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1917 nrKing += (board[r][f] == king); // stm has king
1918 if( board[r][f] != EmptySquare ) {
1919 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1924 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1925 case VariantShatranj:
1926 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1930 if(nrKing == 0) return MT_NOKING;
1933 if(myPieces == 1) return MT_BARE;
1936 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1937 // [HGM] 3check: yet to do!
1939 return inCheck ? MT_CHECK : MT_NONE;
1941 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1942 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1943 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1944 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1945 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1946 if(board[n][holdings] != EmptySquare) {
1947 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1948 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1951 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1952 return myPieces == hisPieces ? MT_STALEMATE :
1953 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1954 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1955 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1957 return inCheck ? MT_CHECKMATE
1958 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1959 MT_STAINMATE : MT_STALEMATE;
1964 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1965 int rf, int ff, int rt, int ft,
1969 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1971 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1972 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1974 // [HGM] wild: for wild-card pieces rt and rf are dummies
1975 if(piece == WhiteFalcon || piece == BlackFalcon ||
1976 piece == WhiteCobra || piece == BlackCobra)
1979 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1980 || PieceToChar(board[rf][ff]) == '~'
1981 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1983 (cl->rfIn == -1 || cl->rfIn == rf) &&
1984 (cl->ffIn == -1 || cl->ffIn == ff) &&
1985 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1986 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1988 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1991 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1992 // [HGM] oneclick: if multiple moves, be sure we remember capture
1993 cl->piece = board[rf][ff];
1996 cl->rt = wildCard ? cl->rtIn : rt;
1997 cl->ft = wildCard ? cl->ftIn : ft;
2000 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
2005 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
2007 int illegal = 0; char c = closure->promoCharIn;
2009 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
2010 closure->count = closure->captures = 0;
2011 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2012 closure->kind = ImpossibleMove;
2013 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
2014 fFilter = closure->ftIn;
2015 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
2016 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2017 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
2018 closure->count = closure->captures = 0;
2019 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2020 closure->kind = ImpossibleMove;
2021 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2024 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2025 if (closure->count == 0) {
2026 /* See if it's an illegal move due to check */
2028 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2029 if (closure->count == 0) {
2030 /* No, it's not even that */
2031 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2032 int f, r; // if there is only a single piece of the requested type on the board, use that
2033 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2034 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2035 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2036 if(closure->count > 1) illegal = 0; // ambiguous
2038 if(closure->count == 0) {
2039 if (appData.debugMode) { int i, j;
2040 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2041 for(j=0; j<BOARD_WIDTH; j++)
2042 fprintf(debugFP, "%3d", (int) board[i][j]);
2043 fprintf(debugFP, "\n");
2049 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2050 DisambiguateClosure spare = *closure;
2051 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2052 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2053 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2057 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2058 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2059 if(closure->piece < BlackPawn) { // white
2060 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2061 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2062 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2063 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2064 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2066 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2067 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2068 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2069 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2070 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2073 if(gameInfo.variant == VariantChu) {
2074 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2076 if(gameInfo.variant == VariantShogi) {
2077 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2078 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2079 ChessSquare piece = closure->piece;
2080 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2081 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2082 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2083 c = '+'; // allowed ICS notations
2084 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2085 else if(flags & F_WHITE_ON_MOVE) {
2086 if( (int) piece < (int) WhiteWazir &&
2087 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2088 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2089 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2090 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2091 else /* promotion optional, default is defer */
2092 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2093 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2095 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2096 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2097 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2098 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2099 else /* promotion optional, default is defer */
2100 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2101 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2104 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2105 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2107 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2108 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2109 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2110 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2111 c = PieceToChar(BlackFerz);
2112 else if(gameInfo.variant == VariantGreat)
2113 c = PieceToChar(BlackMan);
2114 else if(gameInfo.variant == VariantGrand)
2115 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2117 c = PieceToChar(BlackQueen);
2118 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2119 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2120 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2121 ChessSquare p = closure->piece;
2122 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2123 closure->kind = ImpossibleMove; // used on non-promotable piece
2124 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2125 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2127 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2128 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2129 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2130 if (closure->count > 1) {
2131 closure->kind = AmbiguousMove;
2134 /* Note: If more than one illegal move matches, but no legal
2135 moves, we return IllegalMove, not AmbiguousMove. Caller
2136 can look at closure->count to detect this.
2138 closure->kind = IllegalMove;
2152 } CoordsToAlgebraicClosure;
2154 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2155 ChessMove kind, int rf, int ff,
2156 int rt, int ft, VOIDSTAR closure));
2159 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2161 register CoordsToAlgebraicClosure *cl =
2162 (CoordsToAlgebraicClosure *) closure;
2164 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2165 (board[rf][ff] == cl->piece
2166 || PieceToChar(board[rf][ff]) == '~' &&
2167 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2171 cl->kind = kind; /* this is the move we want */
2173 cl->file++; /* need file to rule out this move */
2177 cl->rank++; /* need rank to rule out this move */
2179 cl->either++; /* rank or file will rule out this move */
2185 /* Convert coordinates to normal algebraic notation.
2186 promoChar must be NULLCHAR or 'x' if not a promotion.
2189 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2193 char *outp = out, c, capture;
2194 CoordsToAlgebraicClosure cl;
2196 if (rf == DROP_RANK) {
2197 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2198 /* Bughouse piece drop */
2199 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2204 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2206 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2209 if (promoChar == 'x') promoChar = NULLCHAR;
2210 piece = board[rf][ff];
2211 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2216 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2217 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2218 /* Keep short notation if move is illegal only because it
2219 leaves the player in check, but still return IllegalMove */
2220 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2221 if (kind == IllegalMove) break;
2226 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2227 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2228 /* Non-capture; use style "e5" */
2231 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2233 /* Capture; use style "exd5" */
2235 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2239 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2241 /* Use promotion suffix style "=Q" */
2243 if (promoChar != NULLCHAR) {
2244 if(IS_SHOGI(gameInfo.variant)) {
2245 /* [HGM] ... but not in Shogi! */
2246 *outp++ = promoChar == '=' ? '=' : '+';
2249 *outp++ = ToUpper(promoChar);
2258 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2259 /* Code added by Tord: FRC castling. */
2260 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2261 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2263 safeStrCpy(out, "O-O", MOVE_LEN);
2265 safeStrCpy(out, "O-O-O", MOVE_LEN);
2266 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2268 /* End of code added by Tord */
2269 /* Test for castling or ICS wild castling */
2270 /* Use style "O-O" (oh-oh) for PGN compatibility */
2271 else if (rf == rt &&
2272 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2273 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2274 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2275 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2276 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2277 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2279 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2281 /* This notation is always unambiguous, unless there are
2282 kings on both the d and e files, with "wild castling"
2283 possible for the king on the d file and normal castling
2284 possible for the other. ICS rules for wild 9
2285 effectively make castling illegal for either king in
2286 this situation. So I am not going to worry about it;
2287 I'll just generate an ambiguous O-O in this case.
2289 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2292 /* else fall through */
2297 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2298 cl.ft = fFilter = ft;
2300 cl.kind = IllegalMove;
2301 cl.rank = cl.file = cl.either = 0;
2302 c = PieceToChar(piece) ;
2303 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2305 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2306 /* Generate pretty moves for moving into check, but
2307 still return IllegalMove.
2309 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2310 if (cl.kind == IllegalMove) break;
2311 cl.kind = IllegalMove;
2314 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2315 else "Ngf3" or "Ngxf7",
2316 else "N1f3" or "N5xf7",
2317 else "Ng1f3" or "Ng5xf7".
2319 if( c == '~' || c == '+') {
2320 /* [HGM] print nonexistent piece as its demoted version */
2321 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2323 if(c=='+') *outp++ = c;
2324 *outp++ = ToUpper(PieceToChar(piece));
2326 if (cl.file || (cl.either && !cl.rank)) {
2332 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2335 if(board[rt][ft] != EmptySquare)
2341 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2342 if (IS_SHOGI(gameInfo.variant)) {
2343 /* [HGM] in Shogi non-pawns can promote */
2344 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2346 else if (gameInfo.variant == VariantChuChess && promoChar ||
2347 gameInfo.variant != VariantSuper && promoChar &&
2348 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2350 *outp++ = ToUpper(promoChar);
2352 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2354 *outp++ = ToUpper(promoChar);
2360 /* Moving a nonexistent piece */
2364 /* Not a legal move, even ignoring check.
2365 If there was a piece on the from square,
2366 use style "Ng1g3" or "Ng1xe8";
2367 if there was a pawn or nothing (!),
2368 use style "g1g3" or "g1xe8". Use "x"
2369 if a piece was on the to square, even
2370 a piece of the same color.
2374 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2376 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2377 c += (board[r][f] == piece); // count on-board pieces of given type
2378 *outp++ = ToUpper(PieceToChar(piece));
2380 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2384 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2386 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2390 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2391 /* Use promotion suffix style "=Q" */
2392 if (promoChar != NULLCHAR && promoChar != 'x') {
2394 *outp++ = ToUpper(promoChar);
2401 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2410 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2412 int preyStackPointer, chaseStackPointer;
2415 unsigned char rf, ff, rt, ft;
2419 unsigned char rank, file;
2425 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2427 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2428 int rf, int ff, int rt, int ft,
2432 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2433 { // For adding captures that can lead to chase indictment to the chaseStack
2434 if(board[rt][ft] == EmptySquare) return; // non-capture
2435 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2436 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2437 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2438 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2439 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2440 chaseStack[chaseStackPointer].rf = rf;
2441 chaseStack[chaseStackPointer].ff = ff;
2442 chaseStack[chaseStackPointer].rt = rt;
2443 chaseStack[chaseStackPointer].ft = ft;
2444 chaseStackPointer++;
2447 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2448 int rf, int ff, int rt, int ft,
2452 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2453 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2455 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2457 if(board[rt][ft] == EmptySquare) return; // no capture
2458 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2459 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2461 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2462 for(i=0; i<chaseStackPointer; i++) {
2463 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2464 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2465 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2466 chaseStack[i] = chaseStack[--chaseStackPointer];
2472 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2473 int rf, int ff, int rt, int ft,
2477 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2478 { // for determining if a piece (given through the closure) is protected
2479 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2481 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2482 if(appData.debugMode && board[rt][ft] != EmptySquare)
2483 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2486 extern char moveList[MAX_MOVES][MOVE_LEN];
2489 PerpetualChase (int first, int last)
2490 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2493 ChessSquare captured;
2495 preyStackPointer = 0; // clear stack of chased pieces
2496 for(i=first; i<last; i+=2) { // for all positions with same side to move
2497 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2498 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2499 // determine all captures possible after the move, and put them on chaseStack
2500 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2501 if(appData.debugMode) { int n;
2502 for(n=0; n<chaseStackPointer; n++)
2503 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2504 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2505 fprintf(debugFP, ": all capts\n");
2507 // determine all captures possible before the move, and delete them from chaseStack
2508 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2509 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2510 cl.rt = moveList[i][3]-ONE;
2511 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2512 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2513 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2514 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2515 if(appData.debugMode) { int n;
2516 for(n=0; n<chaseStackPointer; n++)
2517 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2518 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2519 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2521 // chaseSack now contains all captures made possible by the move
2522 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2523 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2524 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2526 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2527 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2529 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2530 continue; // C or H attack on R is always chase; leave on chaseStack
2532 if(attacker == victim) {
2533 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2534 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2535 // we can capture back with equal piece, so this is no chase but a sacrifice
2536 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2537 j--; /* ! */ continue;
2542 // the attack is on a lower piece, or on a pinned or blocked equal one
2543 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2544 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2545 // test if the victim is protected by a true protector. First make the capture.
2546 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2547 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2548 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2549 // Then test if the opponent can recapture
2550 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2551 cl.rt = chaseStack[j].rt;
2552 cl.ft = chaseStack[j].ft;
2553 if(appData.debugMode) {
2554 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2556 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2557 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2558 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2559 // unmake the capture
2560 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2561 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2562 // if a recapture was found, piece is protected, and we are not chasing it.
2563 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2564 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2568 // chaseStack now contains all moves that chased
2569 if(appData.debugMode) { int n;
2570 for(n=0; n<chaseStackPointer; n++)
2571 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2572 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2573 fprintf(debugFP, ": chases\n");
2575 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2576 for(j=0; j<chaseStackPointer; j++) {
2577 preyStack[j].rank = chaseStack[j].rt;
2578 preyStack[j].file = chaseStack[j].ft;
2580 preyStackPointer = chaseStackPointer;
2583 for(j=0; j<chaseStackPointer; j++) {
2584 for(k=0; k<preyStackPointer; k++) {
2585 // search the victim of each chase move on the preyStack (first occurrence)
2586 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2587 if(k < tail) break; // piece was already identified as still being chased
2588 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2589 preyStack[tail] = preyStack[k]; // by swapping
2590 preyStack[k] = preyStack[preyStackPointer];
2596 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2597 if(appData.debugMode) { int n;
2598 for(n=0; n<preyStackPointer; n++)
2599 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2600 fprintf(debugFP, "always chased upto ply %d\n", i);
2602 // now adjust the location of the chased pieces according to opponent move
2603 for(j=0; j<preyStackPointer; j++) {
2604 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2605 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2606 preyStack[j].rank = moveList[i+1][3]-ONE;
2607 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2612 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2613 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the