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
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
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 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
438 if((x == BOARD_RGHT-1 || vx > 0 && board[y][x+1] == DarkSquare) && board[y][x] == initialPosition[y][x])
439 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
442 if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
443 if(occup & mode) cb(board, flags, y == promoRank ? promo : NormalMove, r, f, y, x, cl); // allowed, generate
444 if(occup != 4) break; // not valid transit square
447 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
448 } while(retry-- && ds2); // and start doing them
449 if(tx >= 0) break; // don't do other atoms in continuation legs
453 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
456 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
461 if (rt >= BOARD_HEIGHT) break;
462 if (SameColor(board[rf][ff], board[rt][ft])) break;
463 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
464 if (board[rt][ft] != EmptySquare) break;
469 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
475 if (SameColor(board[rf][ff], board[rt][ft])) break;
476 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
477 if (board[rt][ft] != EmptySquare) break;
482 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
484 SlideForward(board, flags, rf, ff, callback, closure);
485 SlideBackward(board, flags, rf, ff, callback, closure);
489 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
491 int i, s, rt = rf, ft;
492 for(s = -1; s <= 1; s+= 2) {
495 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
496 if (SameColor(board[rf][ff], board[rt][ft])) break;
497 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
498 if (board[rt][ft] != EmptySquare) break;
504 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
507 for(s = -1; s <= 1; s+= 2) {
511 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
512 if (SameColor(board[rf][ff], board[rt][ft])) break;
513 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
514 if (board[rt][ft] != EmptySquare) break;
520 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
523 for(s = -1; s <= 1; s+= 2) {
527 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
528 if (SameColor(board[rf][ff], board[rt][ft])) break;
529 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
530 if (board[rt][ft] != EmptySquare) break;
536 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
538 SlideVertical(board, flags, rf, ff, callback, closure);
539 SlideSideways(board, flags, rf, ff, callback, closure);
543 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
545 SlideDiagForward(board, flags, rf, ff, callback, closure);
546 SlideDiagBackward(board, flags, rf, ff, callback, closure);
550 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
551 { // Lion-like move of Horned Falcon and Souring Eagle
552 int ft = ff + dx, rt = rf + dy;
553 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
555 if (!SameColor(board[rf][ff], board[rt][ft]))
556 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
559 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
561 if (!SameColor(board[rf][ff], board[rt][ft]))
562 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
563 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
564 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
569 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
571 int ft = ff, rt = rf + 1;
572 if (rt >= BOARD_HEIGHT) return;
573 if (SameColor(board[rf][ff], board[rt][ft])) return;
574 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
578 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
580 int ft = ff, rt = rf - 1;
582 if (SameColor(board[rf][ff], board[rt][ft])) return;
583 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
587 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
591 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
592 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
594 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
595 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
599 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
602 if (rt >= BOARD_HEIGHT) return;
604 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
605 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
607 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
608 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
612 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
617 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
618 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
620 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
621 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
625 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
627 StepForward(board, flags, rf, ff, callback, closure);
628 StepBackward(board, flags, rf, ff, callback, closure);
632 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
634 StepDiagForward(board, flags, rf, ff, callback, closure);
635 StepDiagBackward(board, flags, rf, ff, callback, closure);
639 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
641 StepVertical(board, flags, rf, ff, callback, closure);
642 StepSideways(board, flags, rf, ff, callback, closure);
646 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
649 for (i = -1; i <= 1; i += 2)
650 for (j = -1; j <= 1; j += 2)
651 for (s = 1; s <= 2; s++) {
654 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
655 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
656 && !SameColor(board[rf][ff], board[rt][ft]))
657 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
661 /* Call callback once for each pseudo-legal move in the given
662 position, except castling moves. A move is pseudo-legal if it is
663 legal, or if it would be legal except that it leaves the king in
664 check. In the arguments, epfile is EP_NONE if the previous move
665 was not a double pawn push, or the file 0..7 if it was, or
666 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
667 Promotion moves generated are to Queen only.
670 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
671 // speed: only do moves with this piece type
674 int i, j, d, s, fs, rs, rt, ft, m;
675 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
676 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
678 for (rf = 0; rf < BOARD_HEIGHT; rf++)
679 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
682 if(board[rf][ff] == EmptySquare) continue;
683 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
684 m = 0; piece = board[rf][ff];
685 if(PieceToChar(piece) == '~')
686 piece = (ChessSquare) ( DEMOTED piece );
687 if(filter != EmptySquare && piece != filter) continue;
688 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
689 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
692 if(IS_SHOGI(gameInfo.variant))
693 piece = (ChessSquare) ( SHOGI piece );
695 switch ((int)piece) {
696 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
698 /* can't happen ([HGM] except for faries...) */
702 if(gameInfo.variant == VariantXiangqi) {
703 /* [HGM] capture and move straight ahead in Xiangqi */
704 if (rf < BOARD_HEIGHT-1 &&
705 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
706 callback(board, flags, NormalMove,
707 rf, ff, rf + 1, ff, closure);
709 /* and move sideways when across the river */
710 for (s = -1; s <= 1; s += 2) {
711 if (rf >= BOARD_HEIGHT>>1 &&
712 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
713 !WhitePiece(board[rf][ff+s]) ) {
714 callback(board, flags, NormalMove,
715 rf, ff, rf, ff+s, closure);
720 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
721 callback(board, flags,
722 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
723 rf, ff, rf + 1, ff, closure);
725 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
726 gameInfo.variant != VariantShatranj && /* [HGM] */
727 gameInfo.variant != VariantCourier && /* [HGM] */
728 board[rf+2][ff] == EmptySquare ) {
729 callback(board, flags, NormalMove,
730 rf, ff, rf+2, ff, closure);
732 for (s = -1; s <= 1; s += 2) {
733 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
734 ((flags & F_KRIEGSPIEL_CAPTURE) ||
735 BlackPiece(board[rf + 1][ff + s]))) {
736 callback(board, flags,
737 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
738 rf, ff, rf + 1, ff + s, closure);
740 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
741 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
742 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
743 board[rf][ff + s] == BlackPawn &&
744 board[rf+1][ff + s] == EmptySquare) {
745 callback(board, flags, WhiteCapturesEnPassant,
746 rf, ff, rf+1, ff + s, closure);
753 if(gameInfo.variant == VariantXiangqi) {
754 /* [HGM] capture straight ahead in Xiangqi */
755 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
756 callback(board, flags, NormalMove,
757 rf, ff, rf - 1, ff, closure);
759 /* and move sideways when across the river */
760 for (s = -1; s <= 1; s += 2) {
761 if (rf < BOARD_HEIGHT>>1 &&
762 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
763 !BlackPiece(board[rf][ff+s]) ) {
764 callback(board, flags, NormalMove,
765 rf, ff, rf, ff+s, closure);
770 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
771 callback(board, flags,
772 rf <= promoRank ? BlackPromotion : NormalMove,
773 rf, ff, rf - 1, ff, closure);
775 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
776 gameInfo.variant != VariantShatranj && /* [HGM] */
777 gameInfo.variant != VariantCourier && /* [HGM] */
778 board[rf-2][ff] == EmptySquare) {
779 callback(board, flags, NormalMove,
780 rf, ff, rf-2, ff, closure);
782 for (s = -1; s <= 1; s += 2) {
783 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
784 ((flags & F_KRIEGSPIEL_CAPTURE) ||
785 WhitePiece(board[rf - 1][ff + s]))) {
786 callback(board, flags,
787 rf <= promoRank ? BlackPromotion : NormalMove,
788 rf, ff, rf - 1, ff + s, closure);
790 if (rf < BOARD_HEIGHT>>1) {
791 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
792 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
793 board[rf][ff + s] == WhitePawn &&
794 board[rf-1][ff + s] == EmptySquare) {
795 callback(board, flags, BlackCapturesEnPassant,
796 rf, ff, rf-1, ff + s, closure);
806 for (i = -1; i <= 1; i += 2)
807 for (j = -1; j <= 1; j += 2)
808 for (s = 1; s <= 2; s++) {
811 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
812 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
813 && !SameColor(board[rf][ff], board[rt][ft]))
814 callback(board, flags, NormalMove,
815 rf, ff, rt, ft, closure);
819 case SHOGI WhiteKnight:
820 for (s = -1; s <= 1; s += 2) {
821 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
822 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
823 callback(board, flags, NormalMove,
824 rf, ff, rf + 2, ff + s, closure);
829 case SHOGI BlackKnight:
830 for (s = -1; s <= 1; s += 2) {
831 if (rf > 1 && 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);
841 for (d = 0; d <= 1; d++)
842 for (s = -1; s <= 1; s += 2) {
845 rt = rf + (i * s) * d;
846 ft = ff + (i * s) * (1 - d);
847 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
848 if (m == 0 && board[rt][ft] == EmptySquare)
849 callback(board, flags, NormalMove,
850 rf, ff, rt, ft, closure);
851 if (m == 1 && board[rt][ft] != EmptySquare &&
852 !SameColor(board[rf][ff], board[rt][ft]) )
853 callback(board, flags, NormalMove,
854 rf, ff, rt, ft, closure);
855 if (board[rt][ft] != EmptySquare && m++) break;
860 /* Gold General (and all its promoted versions) . First do the */
861 /* diagonal forward steps, then proceed as normal Wazir */
862 case SHOGI (PROMOTED WhitePawn):
863 if(gameInfo.variant == VariantShogi) goto WhiteGold;
864 case SHOGI (PROMOTED BlackPawn):
865 if(gameInfo.variant == VariantShogi) goto BlackGold;
866 SlideVertical(board, flags, rf, ff, callback, closure);
869 case SHOGI (PROMOTED WhiteKnight):
870 if(gameInfo.variant == VariantShogi) goto WhiteGold;
871 case SHOGI BlackDrunk:
872 case SHOGI BlackAlfil:
873 Ferz(board, flags, rf, ff, callback, closure);
874 StepSideways(board, flags, rf, ff, callback, closure);
875 StepBackward(board, flags, rf, ff, callback, closure);
878 case SHOGI (PROMOTED BlackKnight):
879 if(gameInfo.variant == VariantShogi) goto BlackGold;
880 case SHOGI WhiteDrunk:
881 case SHOGI WhiteAlfil:
882 Ferz(board, flags, rf, ff, callback, closure);
883 StepSideways(board, flags, rf, ff, callback, closure);
884 StepForward(board, flags, rf, ff, callback, closure);
888 case SHOGI WhiteStag:
889 case SHOGI BlackStag:
890 if(gameInfo.variant == VariantShogi) goto BlackGold;
891 SlideVertical(board, flags, rf, ff, callback, closure);
892 Ferz(board, flags, rf, ff, callback, closure);
893 StepSideways(board, flags, rf, ff, callback, closure);
896 case SHOGI (PROMOTED WhiteQueen):
897 case SHOGI WhiteTokin:
898 case SHOGI WhiteWazir:
900 StepDiagForward(board, flags, rf, ff, callback, closure);
901 Wazir(board, flags, rf, ff, callback, closure);
904 case SHOGI (PROMOTED BlackQueen):
905 case SHOGI BlackTokin:
906 case SHOGI BlackWazir:
908 StepDiagBackward(board, flags, rf, ff, callback, closure);
909 Wazir(board, flags, rf, ff, callback, closure);
914 Wazir(board, flags, rf, ff, callback, closure);
917 case SHOGI WhiteMarshall:
918 case SHOGI BlackMarshall:
919 Ferz(board, flags, rf, ff, callback, closure);
920 for (d = 0; d <= 1; d++)
921 for (s = -2; s <= 2; s += 4) {
923 ft = ff + s * (1 - d);
924 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
925 if (!SameColor(board[rf][ff], board[rt][ft]) )
926 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
930 case SHOGI WhiteAngel:
931 case SHOGI BlackAngel:
932 Wazir(board, flags, rf, ff, callback, closure);
936 /* [HGM] support Shatranj pieces */
937 for (rs = -1; rs <= 1; rs += 2)
938 for (fs = -1; fs <= 1; fs += 2) {
941 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
942 && ( gameInfo.variant != VariantXiangqi ||
943 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
945 && !SameColor(board[rf][ff], board[rt][ft]))
946 callback(board, flags, NormalMove,
947 rf, ff, rt, ft, closure);
948 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
949 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
950 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
952 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
953 && !SameColor(board[rf][ff], board[rt][ft]))
954 callback(board, flags, NormalMove,
955 rf, ff, rt, ft, closure);
957 if(gameInfo.variant == VariantSpartan)
958 for(fs = -1; fs <= 1; fs += 2) {
960 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
961 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
965 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
968 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
969 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
970 for (s = -2; s <= 2; s += 4) {
972 ft = ff + s * (1 - d);
973 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
974 if (SameColor(board[rf][ff], board[rt][ft])) continue;
975 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
978 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
979 case SHOGI WhiteCardinal:
980 case SHOGI BlackCardinal:
981 case SHOGI WhitePCardinal:
982 case SHOGI BlackPCardinal:
984 Bishop(board, flags, rf, ff, callback, closure);
985 Wazir(board, flags, rf, ff, callback, closure);
988 /* Capablanca Archbishop continues as Knight */
991 Knight(board, flags, rf, ff, callback, closure);
993 /* Shogi Bishops are ordinary Bishops */
994 case SHOGI WhiteBishop:
995 case SHOGI BlackBishop:
996 case SHOGI WhitePBishop:
997 case SHOGI BlackPBishop:
1000 Bishop(board, flags, rf, ff, callback, closure);
1003 /* Shogi Lance is unlike anything, and asymmetric at that */
1004 case SHOGI WhiteQueen:
1005 if(gameInfo.variant == VariantChu) goto doQueen;
1009 if (rt >= BOARD_HEIGHT) break;
1010 if (SameColor(board[rf][ff], board[rt][ft])) break;
1011 callback(board, flags, NormalMove,
1012 rf, ff, rt, ft, closure);
1013 if (board[rt][ft] != EmptySquare) break;
1017 case SHOGI BlackQueen:
1018 if(gameInfo.variant == VariantChu) goto doQueen;
1023 if (SameColor(board[rf][ff], board[rt][ft])) break;
1024 callback(board, flags, NormalMove,
1025 rf, ff, rt, ft, closure);
1026 if (board[rt][ft] != EmptySquare) break;
1030 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1033 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1034 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1035 for (s = -2; s <= 2; s += 4) {
1037 ft = ff + s * (1 - d);
1038 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1039 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1040 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1041 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1043 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1044 Wazir(board, flags, rf, ff, callback, closure);
1046 Rook(board, flags, rf, ff, callback, closure);
1049 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1050 case SHOGI WhiteDragon:
1051 case SHOGI BlackDragon:
1052 case SHOGI WhitePDragon:
1053 case SHOGI BlackPDragon:
1055 Rook(board, flags, rf, ff, callback, closure);
1056 Ferz(board, flags, rf, ff, callback, closure);
1060 /* Capablanca Chancellor sets flag to continue as Knight */
1063 Rook(board, flags, rf, ff, callback, closure);
1064 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1065 Ferz(board, flags, rf, ff, callback, closure);
1067 Knight(board, flags, rf, ff, callback, closure);
1070 /* Shogi Rooks are ordinary Rooks */
1071 case SHOGI WhiteRook:
1072 case SHOGI BlackRook:
1073 case SHOGI WhitePRook:
1074 case SHOGI BlackPRook:
1077 Rook(board, flags, rf, ff, callback, closure);
1082 case SHOGI WhiteMother:
1083 case SHOGI BlackMother:
1085 Rook(board, flags, rf, ff, callback, closure);
1086 Bishop(board, flags, rf, ff, callback, closure);
1089 case SHOGI WhitePawn:
1090 StepForward(board, flags, rf, ff, callback, closure);
1093 case SHOGI BlackPawn:
1094 StepBackward(board, flags, rf, ff, callback, closure);
1098 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1099 case SHOGI WhiteFerz:
1100 Ferz(board, flags, rf, ff, callback, closure);
1101 StepForward(board, flags, rf, ff, callback, closure);
1105 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1106 case SHOGI BlackFerz:
1107 StepBackward(board, flags, rf, ff, callback, closure);
1111 /* [HGM] support Shatranj pieces */
1112 Ferz(board, flags, rf, ff, callback, closure);
1117 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1120 case SHOGI WhiteMonarch:
1121 case SHOGI BlackMonarch:
1122 case SHOGI WhiteKing:
1123 case SHOGI BlackKing:
1126 Ferz(board, flags, rf, ff, callback, closure);
1127 Wazir(board, flags, rf, ff, callback, closure);
1130 case WhiteNightrider:
1131 case BlackNightrider:
1132 for (i = -1; i <= 1; i += 2)
1133 for (j = -1; j <= 1; j += 2)
1134 for (s = 1; s <= 2; s++) { int k;
1137 ft = ff + k*j*(3-s);
1138 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1139 if (SameColor(board[rf][ff], board[rt][ft])) break;
1140 callback(board, flags, NormalMove,
1141 rf, ff, rt, ft, closure);
1142 if (board[rt][ft] != EmptySquare) break;
1148 Bishop(board, flags, rf, ff, callback, closure);
1149 Rook(board, flags, rf, ff, callback, closure);
1150 Knight(board, flags, rf, ff, callback, closure);
1153 // Use Lance as Berolina / Spartan Pawn.
1155 if(gameInfo.variant == VariantSuper) goto Amazon;
1156 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1157 callback(board, flags,
1158 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1159 rf, ff, rf + 1, ff, closure);
1160 for (s = -1; s <= 1; s += 2) {
1161 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1162 callback(board, flags,
1163 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1164 rf, ff, rf + 1, ff + s, closure);
1165 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1166 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1171 if(gameInfo.variant == VariantSuper) goto Amazon;
1172 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1173 callback(board, flags,
1174 rf <= promoRank ? BlackPromotion : NormalMove,
1175 rf, ff, rf - 1, ff, closure);
1176 for (s = -1; s <= 1; s += 2) {
1177 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1178 callback(board, flags,
1179 rf <= promoRank ? BlackPromotion : NormalMove,
1180 rf, ff, rf - 1, ff + s, closure);
1181 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1182 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1186 case SHOGI WhiteNothing:
1187 case SHOGI BlackNothing:
1188 case SHOGI WhiteLion:
1189 case SHOGI BlackLion:
1192 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1193 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1194 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1195 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1196 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1197 rf, ff, rt, ft, closure);
1202 case SHOGI WhiteFalcon:
1203 case SHOGI BlackFalcon:
1204 case SHOGI WhitePDagger:
1205 case SHOGI BlackPDagger:
1206 SlideSideways(board, flags, rf, ff, callback, closure);
1207 StepVertical(board, flags, rf, ff, callback, closure);
1210 case SHOGI WhiteCobra:
1211 case SHOGI BlackCobra:
1212 StepVertical(board, flags, rf, ff, callback, closure);
1215 case SHOGI (PROMOTED WhiteFerz):
1216 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1217 case SHOGI (PROMOTED BlackFerz):
1218 if(gameInfo.variant == VariantShogi) goto BlackGold;
1219 case SHOGI WhitePSword:
1220 case SHOGI BlackPSword:
1221 SlideVertical(board, flags, rf, ff, callback, closure);
1222 StepSideways(board, flags, rf, ff, callback, closure);
1225 case SHOGI WhiteUnicorn:
1226 case SHOGI BlackUnicorn:
1227 Ferz(board, flags, rf, ff, callback, closure);
1228 StepVertical(board, flags, rf, ff, callback, closure);
1231 case SHOGI WhiteMan:
1232 StepDiagForward(board, flags, rf, ff, callback, closure);
1233 StepVertical(board, flags, rf, ff, callback, closure);
1236 case SHOGI BlackMan:
1237 StepDiagBackward(board, flags, rf, ff, callback, closure);
1238 StepVertical(board, flags, rf, ff, callback, closure);
1241 case SHOGI WhiteHCrown:
1242 case SHOGI BlackHCrown:
1243 Bishop(board, flags, rf, ff, callback, closure);
1244 SlideSideways(board, flags, rf, ff, callback, closure);
1247 case SHOGI WhiteCrown:
1248 case SHOGI BlackCrown:
1249 Bishop(board, flags, rf, ff, callback, closure);
1250 SlideVertical(board, flags, rf, ff, callback, closure);
1253 case SHOGI WhiteHorned:
1254 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1255 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1256 if(killX >= 0) break;
1257 Bishop(board, flags, rf, ff, callback, closure);
1258 SlideSideways(board, flags, rf, ff, callback, closure);
1259 SlideBackward(board, flags, rf, ff, callback, closure);
1262 case SHOGI BlackHorned:
1263 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1264 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1265 if(killX >= 0) break;
1266 Bishop(board, flags, rf, ff, callback, closure);
1267 SlideSideways(board, flags, rf, ff, callback, closure);
1268 SlideForward(board, flags, rf, ff, callback, closure);
1271 case SHOGI WhiteEagle:
1272 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1273 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1274 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1275 if(killX >= 0) break;
1276 Rook(board, flags, rf, ff, callback, closure);
1277 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1280 case SHOGI BlackEagle:
1281 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1282 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1283 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1284 if(killX >= 0) break;
1285 Rook(board, flags, rf, ff, callback, closure);
1286 SlideDiagForward(board, flags, rf, ff, callback, closure);
1289 case SHOGI WhiteDolphin:
1290 case SHOGI BlackHorse:
1291 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1292 SlideVertical(board, flags, rf, ff, callback, closure);
1295 case SHOGI BlackDolphin:
1296 case SHOGI WhiteHorse:
1297 SlideDiagForward(board, flags, rf, ff, callback, closure);
1298 SlideVertical(board, flags, rf, ff, callback, closure);
1301 case SHOGI WhiteLance:
1302 SlideForward(board, flags, rf, ff, callback, closure);
1305 case SHOGI BlackLance:
1306 SlideBackward(board, flags, rf, ff, callback, closure);
1309 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1313 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1326 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1327 Board xqCheckers, nullBoard;
1329 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1330 int rf, int ff, int rt, int ft,
1334 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1336 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1338 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1340 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1342 if (!(flags & F_IGNORE_CHECK) ) {
1343 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1346 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1347 kings += (board[r][f] == BlackKing);
1351 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1353 check = CheckTest(board, flags, rf, ff, rt, ft,
1354 kind == WhiteCapturesEnPassant ||
1355 kind == BlackCapturesEnPassant);
1356 if(promo) board[rf][ff] = BlackLance;
1359 if (flags & F_ATOMIC_CAPTURE) {
1360 if (board[rt][ft] != EmptySquare ||
1361 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1363 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1364 if (board[rf][ff] == king) return;
1365 for (r = rt-1; r <= rt+1; r++) {
1366 for (f = ft-1; f <= ft+1; f++) {
1367 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1368 board[r][f] == king) return;
1373 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1380 int captures; // [HGM] losers
1381 } LegalityTestClosure;
1384 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1385 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1386 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1387 moves that would destroy your own king. The CASTLE_OK flags are
1388 true if castling is not yet ruled out by a move of the king or
1389 rook. Return TRUE if the player on move is currently in check and
1390 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1392 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1395 int ff, ft, k, left, right, swap;
1396 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1397 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1398 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1403 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1404 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1405 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1407 if (inCheck) return TRUE;
1409 /* Generate castling moves */
1410 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1411 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1414 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1415 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1417 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1418 if ((flags & F_WHITE_ON_MOVE) &&
1419 (flags & F_WHITE_KCASTLE_OK) &&
1420 board[0][ff] == wKing &&
1421 board[0][ff + 1] == EmptySquare &&
1422 board[0][ff + 2] == EmptySquare &&
1423 board[0][BOARD_RGHT-3] == EmptySquare &&
1424 board[0][BOARD_RGHT-2] == EmptySquare &&
1425 board[0][BOARD_RGHT-1] == WhiteRook &&
1426 castlingRights[0] != NoRights && /* [HGM] check rights */
1427 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1429 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1430 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1431 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1432 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1434 callback(board, flags,
1435 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1436 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1438 if ((flags & F_WHITE_ON_MOVE) &&
1439 (flags & F_WHITE_QCASTLE_OK) &&
1440 board[0][ff] == wKing &&
1441 board[0][ff - 1] == EmptySquare &&
1442 board[0][ff - 2] == EmptySquare &&
1443 board[0][BOARD_LEFT+2] == EmptySquare &&
1444 board[0][BOARD_LEFT+1] == EmptySquare &&
1445 board[0][BOARD_LEFT+0] == WhiteRook &&
1446 castlingRights[1] != NoRights && /* [HGM] check rights */
1447 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1449 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1450 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1451 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1453 callback(board, flags,
1454 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1455 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1457 if (!(flags & F_WHITE_ON_MOVE) &&
1458 (flags & F_BLACK_KCASTLE_OK) &&
1459 board[BOARD_HEIGHT-1][ff] == bKing &&
1460 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1461 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1462 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1463 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1464 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1465 castlingRights[3] != NoRights && /* [HGM] check rights */
1466 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1468 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1469 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1470 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1471 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1473 callback(board, flags,
1474 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1475 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1477 if (!(flags & F_WHITE_ON_MOVE) &&
1478 (flags & F_BLACK_QCASTLE_OK) &&
1479 board[BOARD_HEIGHT-1][ff] == bKing &&
1480 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1481 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1482 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1483 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1484 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1485 castlingRights[4] != NoRights && /* [HGM] check rights */
1486 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1488 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1489 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1490 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1492 callback(board, flags,
1493 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1494 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1498 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1500 /* generate all potential FRC castling moves (KxR), ignoring flags */
1501 /* [HGM] test if the Rooks we find have castling rights */
1502 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1505 if ((flags & F_WHITE_ON_MOVE) != 0) {
1506 ff = castlingRights[2]; /* King file if we have any rights */
1507 if(ff != NoRights && board[0][ff] == WhiteKing) {
1508 if (appData.debugMode) {
1509 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1510 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1512 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1514 right = BOARD_RGHT-2;
1515 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1516 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1517 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1518 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1519 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1520 if(ft != NoRights && board[0][ft] == WhiteRook) {
1521 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1522 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1525 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1526 left = BOARD_LEFT+2;
1528 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1529 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1530 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1531 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1532 if(ff > BOARD_LEFT+2)
1533 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1534 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1535 if(ft != NoRights && board[0][ft] == WhiteRook) {
1536 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1537 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1541 ff = castlingRights[5]; /* King file if we have any rights */
1542 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1543 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1545 right = BOARD_RGHT-2;
1546 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1547 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1548 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1549 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1550 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1551 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1552 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1553 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1556 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1557 left = BOARD_LEFT+2;
1559 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1560 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1561 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1562 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1563 if(ff > BOARD_LEFT+2)
1564 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1565 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1566 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1567 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1568 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1585 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1586 int rf, int ff, int rt, int ft,
1591 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1593 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1595 if (rt == cl->rking && ft == cl->fking) {
1596 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1598 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1600 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1601 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1602 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1606 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1607 he leave himself in check? Or if rf == -1, is the player on move
1608 in check now? enPassant must be TRUE if the indicated move is an
1609 e.p. capture. The possibility of castling out of a check along the
1610 back rank is not accounted for (i.e., we still return nonzero), as
1611 this is illegal anyway. Return value is the number of times the
1612 king is in check. */
1614 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1616 CheckTestClosure cl;
1617 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1618 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1619 int saveKill = killX;
1620 /* Suppress warnings on uninitialized variables */
1622 if(gameInfo.variant == VariantXiangqi)
1623 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1624 if(gameInfo.variant == VariantKnightmate)
1625 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1626 if(gameInfo.variant == VariantChu || gameInfo.variant == VariantShogi) { // strictly speaking this is not needed, as Chu officially has no check
1627 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1628 if(gameInfo.variant == VariantShogi) prince -= 11; // White/BlackFalcon
1629 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1630 if(board[r][f] == k || board[r][f] == prince) {
1631 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1632 king = board[r][f]; // remember hich one we had
1639 captured = board[rf][ft];
1640 board[rf][ft] = EmptySquare;
1642 captured = board[rt][ft];
1643 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; }
1645 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1646 board[rt][ft] = board[rf][ff];
1647 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1649 ep = board[EP_STATUS];
1650 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1651 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1652 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1653 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1654 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1655 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1659 /* For compatibility with ICS wild 9, we scan the board in the
1660 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1661 and we test only whether that one is in check. */
1662 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1663 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1664 if (board[cl.rking][cl.fking] == king) {
1666 if(gameInfo.variant == VariantXiangqi) {
1667 /* [HGM] In Xiangqi opposing Kings means check as well */
1669 dir = (king >= BlackPawn) ? -1 : 1;
1670 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1671 board[i][cl.fking] == EmptySquare; i+=dir );
1672 if(i>=0 && i<BOARD_HEIGHT &&
1673 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1676 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1677 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1678 goto undo_move; /* 2-level break */
1685 if(rf != DROP_RANK) // [HGM] drop
1686 board[rf][ff] = board[rt][ft];
1688 board[rf][ft] = captured;
1689 board[rt][ft] = EmptySquare;
1691 if(saveKill >= 0) board[killY][killX] = trampled, killX = saveKill;
1692 board[rt][ft] = captured;
1694 board[EP_STATUS] = ep;
1697 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1701 HasLion (Board board, int flags)
1703 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1705 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1706 if(board[r][f] == lion) return 1;
1711 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1712 { // [HGM] put drop legality testing in separate routine for clarity
1714 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1715 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1716 n = PieceToNumber(piece);
1717 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1718 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1719 return ImpossibleMove; // piece not available
1720 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1721 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1722 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1723 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1724 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1725 if(piece == WhitePawn || piece == BlackPawn) {
1726 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1727 for(r=1; r<BOARD_HEIGHT-1; r++)
1728 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1729 // should still test if we mate with this Pawn
1731 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1732 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1734 if( (piece == WhitePawn || piece == BlackPawn) &&
1735 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1736 return IllegalMove; /* no pawn drops on 1st/8th */
1738 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1739 if (!(flags & F_IGNORE_CHECK) &&
1740 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1741 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1744 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1745 int rf, int ff, int rt, int ft,
1749 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1751 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1753 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1754 cl->captures++; // [HGM] losers: count legal captures
1755 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1760 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1762 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1764 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1765 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1766 piece = filterPiece = board[rf][ff];
1767 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1769 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1770 /* (perhaps we should disallow moves that obviously leave us in check?) */
1771 if((piece == WhiteFalcon || piece == BlackFalcon ||
1772 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1773 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1777 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1778 cl.ft = fFilter = ft;
1779 cl.kind = IllegalMove;
1780 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1781 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1782 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1783 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1784 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1785 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1787 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1788 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1789 if(board[rf][ff] < BlackPawn) { // white
1790 if(rf != 0) return IllegalMove; // must be on back rank
1791 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1792 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1793 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1794 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1796 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1797 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1798 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1799 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1800 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1803 if(gameInfo.variant == VariantChu) {
1804 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1805 if(promoChar != '+')
1806 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1807 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1808 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1810 if(gameInfo.variant == VariantShogi) {
1811 /* [HGM] Shogi promotions. '=' means defer */
1812 if(rf != DROP_RANK && cl.kind == NormalMove) {
1813 ChessSquare piece = board[rf][ff];
1815 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1816 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1817 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1818 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1819 promoChar = '+'; // allowed ICS notations
1820 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1821 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1822 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1823 else if(flags & F_WHITE_ON_MOVE) {
1824 if( (int) piece < (int) WhiteWazir &&
1825 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1826 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1827 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1828 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1829 else /* promotion optional, default is defer */
1830 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1831 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1833 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1834 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1835 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1836 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1837 else /* promotion optional, default is defer */
1838 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1839 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1843 if (promoChar != NULLCHAR) {
1844 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1845 ChessSquare piece = board[rf][ff];
1846 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1847 // should test if in zone, really
1848 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1850 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1852 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1853 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1854 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1855 if(piece == EmptySquare)
1856 cl.kind = ImpossibleMove; // non-existing piece
1857 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1858 cl.kind = IllegalMove; // no two Lions
1859 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1860 if(promoChar != PieceToChar(BlackKing)) {
1861 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1862 if(piece == BlackLance) cl.kind = ImpossibleMove;
1863 } else { // promotion to King allowed only if we do not have two yet
1864 int r, f, kings = 0;
1865 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1866 if(kings == 2) cl.kind = IllegalMove;
1868 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1869 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1870 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1871 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1872 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1873 cl.kind = IllegalMove; // promotion to King usually not allowed
1875 cl.kind = IllegalMove;
1885 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1886 int rf, int ff, int rt, int ft,
1890 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1892 register MateTestClosure *cl = (MateTestClosure *) closure;
1897 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1899 MateTest (Board board, int flags)
1902 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1903 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1905 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1906 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1907 nrKing += (board[r][f] == king); // stm has king
1908 if( board[r][f] != EmptySquare ) {
1909 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1914 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1915 case VariantShatranj:
1916 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1920 if(nrKing == 0) return MT_NOKING;
1923 if(myPieces == 1) return MT_BARE;
1926 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1927 // [HGM] 3check: yet to do!
1929 return inCheck ? MT_CHECK : MT_NONE;
1931 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1932 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1933 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1934 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1935 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1936 if(board[n][holdings] != EmptySquare) {
1937 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1938 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1941 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1942 return myPieces == hisPieces ? MT_STALEMATE :
1943 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1944 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1945 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1947 return inCheck ? MT_CHECKMATE
1948 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1949 MT_STAINMATE : MT_STALEMATE;
1954 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1955 int rf, int ff, int rt, int ft,
1959 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1961 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1962 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1964 // [HGM] wild: for wild-card pieces rt and rf are dummies
1965 if(piece == WhiteFalcon || piece == BlackFalcon ||
1966 piece == WhiteCobra || piece == BlackCobra)
1969 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1970 || PieceToChar(board[rf][ff]) == '~'
1971 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1973 (cl->rfIn == -1 || cl->rfIn == rf) &&
1974 (cl->ffIn == -1 || cl->ffIn == ff) &&
1975 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1976 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1978 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1981 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1982 // [HGM] oneclick: if multiple moves, be sure we remember capture
1983 cl->piece = board[rf][ff];
1986 cl->rt = wildCard ? cl->rtIn : rt;
1987 cl->ft = wildCard ? cl->ftIn : ft;
1990 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1995 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1997 int illegal = 0; char c = closure->promoCharIn;
1999 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
2000 closure->count = closure->captures = 0;
2001 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2002 closure->kind = ImpossibleMove;
2003 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
2004 fFilter = closure->ftIn;
2005 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
2006 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2007 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
2008 closure->count = closure->captures = 0;
2009 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2010 closure->kind = ImpossibleMove;
2011 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2014 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2015 if (closure->count == 0) {
2016 /* See if it's an illegal move due to check */
2018 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2019 if (closure->count == 0) {
2020 /* No, it's not even that */
2021 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2022 int f, r; // if there is only a single piece of the requested type on the board, use that
2023 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2024 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2025 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2026 if(closure->count > 1) illegal = 0; // ambiguous
2028 if(closure->count == 0) {
2029 if (appData.debugMode) { int i, j;
2030 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2031 for(j=0; j<BOARD_WIDTH; j++)
2032 fprintf(debugFP, "%3d", (int) board[i][j]);
2033 fprintf(debugFP, "\n");
2039 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2040 DisambiguateClosure spare = *closure;
2041 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2042 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2043 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2047 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2048 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2049 if(closure->piece < BlackPawn) { // white
2050 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2051 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2052 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2053 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2054 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2056 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2057 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2058 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2059 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2060 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2063 if(gameInfo.variant == VariantChu) {
2064 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2066 if(gameInfo.variant == VariantShogi) {
2067 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2068 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2069 ChessSquare piece = closure->piece;
2070 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2071 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2072 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2073 c = '+'; // allowed ICS notations
2074 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2075 else if(flags & F_WHITE_ON_MOVE) {
2076 if( (int) piece < (int) WhiteWazir &&
2077 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2078 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2079 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2080 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2081 else /* promotion optional, default is defer */
2082 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2083 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2085 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2086 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2087 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2088 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2089 else /* promotion optional, default is defer */
2090 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2091 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2094 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2095 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2097 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2098 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2099 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2100 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2101 c = PieceToChar(BlackFerz);
2102 else if(gameInfo.variant == VariantGreat)
2103 c = PieceToChar(BlackMan);
2104 else if(gameInfo.variant == VariantGrand)
2105 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2107 c = PieceToChar(BlackQueen);
2108 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2109 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2110 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2111 ChessSquare p = closure->piece;
2112 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2113 closure->kind = ImpossibleMove; // used on non-promotable piece
2114 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2115 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2117 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2118 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2119 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2120 if (closure->count > 1) {
2121 closure->kind = AmbiguousMove;
2124 /* Note: If more than one illegal move matches, but no legal
2125 moves, we return IllegalMove, not AmbiguousMove. Caller
2126 can look at closure->count to detect this.
2128 closure->kind = IllegalMove;
2142 } CoordsToAlgebraicClosure;
2144 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2145 ChessMove kind, int rf, int ff,
2146 int rt, int ft, VOIDSTAR closure));
2149 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2151 register CoordsToAlgebraicClosure *cl =
2152 (CoordsToAlgebraicClosure *) closure;
2154 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2155 (board[rf][ff] == cl->piece
2156 || PieceToChar(board[rf][ff]) == '~' &&
2157 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2161 cl->kind = kind; /* this is the move we want */
2163 cl->file++; /* need file to rule out this move */
2167 cl->rank++; /* need rank to rule out this move */
2169 cl->either++; /* rank or file will rule out this move */
2175 /* Convert coordinates to normal algebraic notation.
2176 promoChar must be NULLCHAR or 'x' if not a promotion.
2179 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2183 char *outp = out, c, capture;
2184 CoordsToAlgebraicClosure cl;
2186 if (rf == DROP_RANK) {
2187 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2188 /* Bughouse piece drop */
2189 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2194 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2196 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2199 if (promoChar == 'x') promoChar = NULLCHAR;
2200 piece = board[rf][ff];
2201 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2206 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2207 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2208 /* Keep short notation if move is illegal only because it
2209 leaves the player in check, but still return IllegalMove */
2210 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2211 if (kind == IllegalMove) break;
2216 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2217 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2218 /* Non-capture; use style "e5" */
2221 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2223 /* Capture; use style "exd5" */
2225 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2229 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2231 /* Use promotion suffix style "=Q" */
2233 if (promoChar != NULLCHAR) {
2234 if(IS_SHOGI(gameInfo.variant)) {
2235 /* [HGM] ... but not in Shogi! */
2236 *outp++ = promoChar == '=' ? '=' : '+';
2239 *outp++ = ToUpper(promoChar);
2248 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2249 /* Code added by Tord: FRC castling. */
2250 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2251 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2253 safeStrCpy(out, "O-O", MOVE_LEN);
2255 safeStrCpy(out, "O-O-O", MOVE_LEN);
2256 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2258 /* End of code added by Tord */
2259 /* Test for castling or ICS wild castling */
2260 /* Use style "O-O" (oh-oh) for PGN compatibility */
2261 else if (rf == rt &&
2262 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2263 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2264 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2265 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2266 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2267 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2269 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2271 /* This notation is always unambiguous, unless there are
2272 kings on both the d and e files, with "wild castling"
2273 possible for the king on the d file and normal castling
2274 possible for the other. ICS rules for wild 9
2275 effectively make castling illegal for either king in
2276 this situation. So I am not going to worry about it;
2277 I'll just generate an ambiguous O-O in this case.
2279 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2282 /* else fall through */
2287 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2288 cl.ft = fFilter = ft;
2290 cl.kind = IllegalMove;
2291 cl.rank = cl.file = cl.either = 0;
2292 c = PieceToChar(piece) ;
2293 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2295 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2296 /* Generate pretty moves for moving into check, but
2297 still return IllegalMove.
2299 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2300 if (cl.kind == IllegalMove) break;
2301 cl.kind = IllegalMove;
2304 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2305 else "Ngf3" or "Ngxf7",
2306 else "N1f3" or "N5xf7",
2307 else "Ng1f3" or "Ng5xf7".
2309 if( c == '~' || c == '+') {
2310 /* [HGM] print nonexistent piece as its demoted version */
2311 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2313 if(c=='+') *outp++ = c;
2314 *outp++ = ToUpper(PieceToChar(piece));
2316 if (cl.file || (cl.either && !cl.rank)) {
2322 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2325 if(board[rt][ft] != EmptySquare)
2331 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2332 if (IS_SHOGI(gameInfo.variant)) {
2333 /* [HGM] in Shogi non-pawns can promote */
2334 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2336 else if (gameInfo.variant == VariantChuChess && promoChar ||
2337 gameInfo.variant != VariantSuper && promoChar &&
2338 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2340 *outp++ = ToUpper(promoChar);
2342 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2344 *outp++ = ToUpper(promoChar);
2350 /* Moving a nonexistent piece */
2354 /* Not a legal move, even ignoring check.
2355 If there was a piece on the from square,
2356 use style "Ng1g3" or "Ng1xe8";
2357 if there was a pawn or nothing (!),
2358 use style "g1g3" or "g1xe8". Use "x"
2359 if a piece was on the to square, even
2360 a piece of the same color.
2364 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2366 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2367 c += (board[r][f] == piece); // count on-board pieces of given type
2368 *outp++ = ToUpper(PieceToChar(piece));
2370 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2374 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2376 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2380 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2381 /* Use promotion suffix style "=Q" */
2382 if (promoChar != NULLCHAR && promoChar != 'x') {
2384 *outp++ = ToUpper(promoChar);
2391 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2400 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2402 int preyStackPointer, chaseStackPointer;
2405 unsigned char rf, ff, rt, ft;
2409 unsigned char rank, file;
2415 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2417 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2418 int rf, int ff, int rt, int ft,
2422 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2423 { // For adding captures that can lead to chase indictment to the chaseStack
2424 if(board[rt][ft] == EmptySquare) return; // non-capture
2425 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2426 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2427 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2428 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2429 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2430 chaseStack[chaseStackPointer].rf = rf;
2431 chaseStack[chaseStackPointer].ff = ff;
2432 chaseStack[chaseStackPointer].rt = rt;
2433 chaseStack[chaseStackPointer].ft = ft;
2434 chaseStackPointer++;
2437 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2438 int rf, int ff, int rt, int ft,
2442 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2443 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2445 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2447 if(board[rt][ft] == EmptySquare) return; // no capture
2448 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2449 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2451 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2452 for(i=0; i<chaseStackPointer; i++) {
2453 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2454 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2455 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2456 chaseStack[i] = chaseStack[--chaseStackPointer];
2462 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2463 int rf, int ff, int rt, int ft,
2467 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2468 { // for determining if a piece (given through the closure) is protected
2469 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2471 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2472 if(appData.debugMode && board[rt][ft] != EmptySquare)
2473 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2476 extern char moveList[MAX_MOVES][MOVE_LEN];
2479 PerpetualChase (int first, int last)
2480 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2483 ChessSquare captured;
2485 preyStackPointer = 0; // clear stack of chased pieces
2486 for(i=first; i<last; i+=2) { // for all positions with same side to move
2487 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2488 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2489 // determine all captures possible after the move, and put them on chaseStack
2490 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2491 if(appData.debugMode) { int n;
2492 for(n=0; n<chaseStackPointer; n++)
2493 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2494 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2495 fprintf(debugFP, ": all capts\n");
2497 // determine all captures possible before the move, and delete them from chaseStack
2498 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2499 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2500 cl.rt = moveList[i][3]-ONE;
2501 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2502 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2503 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2504 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2505 if(appData.debugMode) { int n;
2506 for(n=0; n<chaseStackPointer; n++)
2507 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2508 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2509 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2511 // chaseSack now contains all captures made possible by the move
2512 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2513 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2514 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2516 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2517 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2519 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2520 continue; // C or H attack on R is always chase; leave on chaseStack
2522 if(attacker == victim) {
2523 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2524 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2525 // we can capture back with equal piece, so this is no chase but a sacrifice
2526 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2527 j--; /* ! */ continue;
2532 // the attack is on a lower piece, or on a pinned or blocked equal one
2533 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2534 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2535 // test if the victim is protected by a true protector. First make the capture.
2536 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2537 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2538 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2539 // Then test if the opponent can recapture
2540 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2541 cl.rt = chaseStack[j].rt;
2542 cl.ft = chaseStack[j].ft;
2543 if(appData.debugMode) {
2544 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2546 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2547 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2548 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2549 // unmake the capture
2550 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2551 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2552 // if a recapture was found, piece is protected, and we are not chasing it.
2553 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2554 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2558 // chaseStack now contains all moves that chased
2559 if(appData.debugMode) { int n;
2560 for(n=0; n<chaseStackPointer; n++)
2561 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2562 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2563 fprintf(debugFP, ": chases\n");
2565 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2566 for(j=0; j<chaseStackPointer; j++) {
2567 preyStack[j].rank = chaseStack[j].rt;
2568 preyStack[j].file = chaseStack[j].ft;
2570 preyStackPointer = chaseStackPointer;
2573 for(j=0; j<chaseStackPointer; j++) {
2574 for(k=0; k<preyStackPointer; k++) {
2575 // search the victim of each chase move on the preyStack (first occurrence)
2576 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2577 if(k < tail) break; // piece was already identified as still being chased
2578 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2579 preyStack[tail] = preyStack[k]; // by swapping
2580 preyStack[k] = preyStack[preyStackPointer];
2586 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2587 if(appData.debugMode) { int n;
2588 for(n=0; n<preyStackPointer; n++)
2589 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2590 fprintf(debugFP, "always chased upto ply %d\n", i);
2592 // now adjust the location of the chased pieces according to opponent move
2593 for(j=0; j<preyStackPointer; j++) {
2594 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2595 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2596 preyStack[j].rank = moveList[i+1][3]-ONE;
2597 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2602 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2603 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the