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
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22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
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29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
61 #else /* not HAVE_STRING_H */
63 #endif /* not HAVE_STRING_H */
69 int WhitePiece P((ChessSquare));
70 int BlackPiece P((ChessSquare));
71 int SameColor P((ChessSquare, ChessSquare));
72 int PosFlags(int index);
74 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
76 char *pieceDesc[EmptySquare];
77 char *defaultDesc[EmptySquare] = {
78 "fmWfceFifmnD", "N", "B", "R", "Q",
79 "F", "A", "BN", "RN", "W", "K",
80 "mRcpR", "N0", "BW", "RF", "gQ",
81 "", "", "QN", "", "N", "",
83 "", "", "", "", "", "",
85 "", "", "", "", "", "K"
89 WhitePiece (ChessSquare piece)
91 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
95 BlackPiece (ChessSquare piece)
97 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
102 SameColor (ChessSquare piece1, ChessSquare piece2)
104 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
105 (int) piece1 < (int) BlackPawn &&
106 (int) piece2 >= (int) WhitePawn &&
107 (int) piece2 < (int) BlackPawn)
108 || ((int) piece1 >= (int) BlackPawn &&
109 (int) piece1 < (int) EmptySquare &&
110 (int) piece2 >= (int) BlackPawn &&
111 (int) piece2 < (int) EmptySquare);
114 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
117 char pieceToChar[] = {
118 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
119 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
120 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
121 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
123 char pieceNickName[EmptySquare];
126 PieceToChar (ChessSquare p)
128 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
129 return pieceToChar[(int) p];
133 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
136 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
138 while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
146 if(c == '.') return EmptySquare;
147 for(i=0; i< (int) EmptySquare; i++)
148 if(pieceNickName[i] == c) return (ChessSquare) i;
149 for(i=0; i< (int) EmptySquare; i++)
150 if(pieceToChar[i] == c) return (ChessSquare) i;
155 CopyBoard (Board to, Board from)
159 for (i = 0; i < BOARD_HEIGHT; i++)
160 for (j = 0; j < BOARD_WIDTH; j++)
161 to[i][j] = from[i][j];
162 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
163 to[VIRGIN][j] = from[VIRGIN][j],
164 to[CASTLING][j] = from[CASTLING][j];
165 to[HOLDINGS_SET] = 0; // flag used in ICS play
169 CompareBoards (Board board1, Board board2)
173 for (i = 0; i < BOARD_HEIGHT; i++)
174 for (j = 0; j < BOARD_WIDTH; j++) {
175 if (board1[i][j] != board2[i][j])
181 char defaultName[] = "PNBRQ......................................K" // white
182 "pnbrq......................................k"; // black
183 char shogiName[] = "PNBRLS...G.++++++..........................K" // white
184 "pnbrls...g.++++++..........................k"; // black
185 char xqName[] = "PH.R.AE..K.C................................" // white
186 "ph.r.ae..k.c................................"; // black
189 CollectPieceDescriptors ()
190 { // make a line of piece descriptions for use in the PGN Piece tag:
191 // dump all engine defined pieces, and pieces with non-standard names,
192 // but suppress black pieces that are the same as their white counterpart
194 static char buf[MSG_SIZ];
195 char *m, c, d, *pieceName = defaultName;
198 if(!pieceDefs) return "";
199 if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
200 if(gameInfo.variant == VariantShogi) pieceName = shogiName;
201 if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
202 for(p=WhitePawn; p<EmptySquare; p++) {
203 if((c = pieceToChar[p]) == '.' || c == '~') continue; // does not participate
204 m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED p] : c);
205 if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == toupper(c)
206 && (c != '+' || pieceToChar[DEMOTED BLACK_TO_WHITE p] == d)) { // black member of normal pair
207 char *wm = pieceDesc[BLACK_TO_WHITE p];
208 if(!m && !wm || m && wm && !strcmp(wm, m)) continue; // moves as a white piece
209 } else // white or unpaired black
210 if((p < BlackPawn || CharToPiece(toupper(d)) != EmptySquare) && // white or lone black
211 !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
212 // TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
213 if(!m) m = defaultDesc[p];
215 snprintf(buf+len, MSG_SIZ-len, "%s%s%c:%s", len ? ";" : "", c == '+' ? "+" : "", d, m);
220 // [HGM] gen: configurable move generation from Betza notation sent by engine.
221 // Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
222 // square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
223 // if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
224 // target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
225 // is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
226 // user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
227 // generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
228 // can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
229 // 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
233 // alphabet "abcdefghijklmnopqrstuvwxyz"
234 char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
235 char xStep[] = "2110.130.102.10.00....0..2";
236 char yStep[] = "2132.133.313.20.11....1..3";
237 char dirType[] = "01000104000200000260050000";
238 char upgrade[] = "AFCD.BGH.JQL.NO.KW....R..Z";
239 char rotate[] = "DRCA.WHG.JKL.NO.QB....F..Z";
241 // alphabet "a b c d e f g h i j k l m n o p q r s t u v w x y z "
242 int dirs1[] = { 0,0x3C,0,0,0,0xC3,0,0, 0,0,0,0xF0,0,0,0,0,0,0x0F,0 ,0,0,0 ,0,0,0,0 };
243 int dirs2[] = { 0,0x18,0,0,0,0x81,0,0xFF,0,0,0,0x60,0,0,0,0,0,0x06,0x66,0,0,0x99,0,0,0,0 };
244 int dirs3[] = { 0,0x38,0,0,0,0x83,0,0xFF,0,0,0,0xE0,0,0,0,0,0,0x0E,0xEE,0,0,0xBB,0,0,0,0 };
245 int dirs4[] = { 0,0x10,0,0,0,0x01,0,0xFF,0,0,0,0x40,0,0,0,0,0,0x04,0x44,0,0,0x11,0,0,0,0 };
247 int rot[][4] = { // rotation matrices for each direction
259 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
265 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
267 char buf[80], *p = desc, *atom = NULL;
268 int mine, his, dir, bit, occup, i, 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
429 if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
430 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
432 if(mode & 1024) { // castling
433 i = 2; // kludge to elongate move indefinitely
434 if(occup == 4) continue; // skip empty squares
435 if(x == BOARD_LEFT && board[y][x] == initialPosition[y][x]) // reached initial corner piece
436 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
437 if(x == BOARD_RGHT-1 && board[y][x] == initialPosition[y][x])
438 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
441 if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
442 if(occup & mode) cb(board, flags, y == promoRank ? promo : NormalMove, r, f, y, x, cl); // allowed, generate
443 if(occup != 4) break; // not valid transit square
446 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
447 } while(retry-- && ds2); // and start doing them
448 if(tx >= 0) break; // don't do other atoms in continuation legs
452 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
455 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
460 if (rt >= BOARD_HEIGHT) break;
461 if (SameColor(board[rf][ff], board[rt][ft])) break;
462 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
463 if (board[rt][ft] != EmptySquare) break;
468 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
474 if (SameColor(board[rf][ff], board[rt][ft])) break;
475 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
476 if (board[rt][ft] != EmptySquare) break;
481 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
483 SlideForward(board, flags, rf, ff, callback, closure);
484 SlideBackward(board, flags, rf, ff, callback, closure);
488 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
490 int i, s, rt = rf, ft;
491 for(s = -1; s <= 1; s+= 2) {
494 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
495 if (SameColor(board[rf][ff], board[rt][ft])) break;
496 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
497 if (board[rt][ft] != EmptySquare) break;
503 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
506 for(s = -1; s <= 1; s+= 2) {
510 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
511 if (SameColor(board[rf][ff], board[rt][ft])) break;
512 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
513 if (board[rt][ft] != EmptySquare) break;
519 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
522 for(s = -1; s <= 1; s+= 2) {
526 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
527 if (SameColor(board[rf][ff], board[rt][ft])) break;
528 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
529 if (board[rt][ft] != EmptySquare) break;
535 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
537 SlideVertical(board, flags, rf, ff, callback, closure);
538 SlideSideways(board, flags, rf, ff, callback, closure);
542 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
544 SlideDiagForward(board, flags, rf, ff, callback, closure);
545 SlideDiagBackward(board, flags, rf, ff, callback, closure);
549 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
550 { // Lion-like move of Horned Falcon and Souring Eagle
551 int ft = ff + dx, rt = rf + dy;
552 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
554 if (!SameColor(board[rf][ff], board[rt][ft]))
555 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
558 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
560 if (!SameColor(board[rf][ff], board[rt][ft]))
561 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
562 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
563 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
568 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
570 int ft = ff, rt = rf + 1;
571 if (rt >= BOARD_HEIGHT) return;
572 if (SameColor(board[rf][ff], board[rt][ft])) return;
573 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
577 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
579 int ft = ff, rt = rf - 1;
581 if (SameColor(board[rf][ff], board[rt][ft])) return;
582 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
586 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
590 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
591 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
593 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
594 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
598 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
601 if (rt >= BOARD_HEIGHT) return;
603 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
604 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
606 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
607 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
611 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
616 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
617 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
619 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
620 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
624 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
626 StepForward(board, flags, rf, ff, callback, closure);
627 StepBackward(board, flags, rf, ff, callback, closure);
631 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
633 StepDiagForward(board, flags, rf, ff, callback, closure);
634 StepDiagBackward(board, flags, rf, ff, callback, closure);
638 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
640 StepVertical(board, flags, rf, ff, callback, closure);
641 StepSideways(board, flags, rf, ff, callback, closure);
645 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
648 for (i = -1; i <= 1; i += 2)
649 for (j = -1; j <= 1; j += 2)
650 for (s = 1; s <= 2; s++) {
653 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
654 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
655 && !SameColor(board[rf][ff], board[rt][ft]))
656 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
660 /* Call callback once for each pseudo-legal move in the given
661 position, except castling moves. A move is pseudo-legal if it is
662 legal, or if it would be legal except that it leaves the king in
663 check. In the arguments, epfile is EP_NONE if the previous move
664 was not a double pawn push, or the file 0..7 if it was, or
665 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
666 Promotion moves generated are to Queen only.
669 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
670 // speed: only do moves with this piece type
673 int i, j, d, s, fs, rs, rt, ft, m;
674 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
675 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
677 for (rf = 0; rf < BOARD_HEIGHT; rf++)
678 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
681 if(board[rf][ff] == EmptySquare) continue;
682 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
683 m = 0; piece = board[rf][ff];
684 if(PieceToChar(piece) == '~')
685 piece = (ChessSquare) ( DEMOTED piece );
686 if(filter != EmptySquare && piece != filter) continue;
687 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
688 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
691 if(IS_SHOGI(gameInfo.variant))
692 piece = (ChessSquare) ( SHOGI piece );
694 switch ((int)piece) {
695 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
697 /* can't happen ([HGM] except for faries...) */
701 if(gameInfo.variant == VariantXiangqi) {
702 /* [HGM] capture and move straight ahead in Xiangqi */
703 if (rf < BOARD_HEIGHT-1 &&
704 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
705 callback(board, flags, NormalMove,
706 rf, ff, rf + 1, ff, closure);
708 /* and move sideways when across the river */
709 for (s = -1; s <= 1; s += 2) {
710 if (rf >= BOARD_HEIGHT>>1 &&
711 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
712 !WhitePiece(board[rf][ff+s]) ) {
713 callback(board, flags, NormalMove,
714 rf, ff, rf, ff+s, closure);
719 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
720 callback(board, flags,
721 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
722 rf, ff, rf + 1, ff, closure);
724 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
725 gameInfo.variant != VariantShatranj && /* [HGM] */
726 gameInfo.variant != VariantCourier && /* [HGM] */
727 board[rf+2][ff] == EmptySquare ) {
728 callback(board, flags, NormalMove,
729 rf, ff, rf+2, ff, closure);
731 for (s = -1; s <= 1; s += 2) {
732 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
733 ((flags & F_KRIEGSPIEL_CAPTURE) ||
734 BlackPiece(board[rf + 1][ff + s]))) {
735 callback(board, flags,
736 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
737 rf, ff, rf + 1, ff + s, closure);
739 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
740 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
741 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
742 board[rf][ff + s] == BlackPawn &&
743 board[rf+1][ff + s] == EmptySquare) {
744 callback(board, flags, WhiteCapturesEnPassant,
745 rf, ff, rf+1, ff + s, closure);
752 if(gameInfo.variant == VariantXiangqi) {
753 /* [HGM] capture straight ahead in Xiangqi */
754 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
755 callback(board, flags, NormalMove,
756 rf, ff, rf - 1, ff, closure);
758 /* and move sideways when across the river */
759 for (s = -1; s <= 1; s += 2) {
760 if (rf < BOARD_HEIGHT>>1 &&
761 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
762 !BlackPiece(board[rf][ff+s]) ) {
763 callback(board, flags, NormalMove,
764 rf, ff, rf, ff+s, closure);
769 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
770 callback(board, flags,
771 rf <= promoRank ? BlackPromotion : NormalMove,
772 rf, ff, rf - 1, ff, closure);
774 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
775 gameInfo.variant != VariantShatranj && /* [HGM] */
776 gameInfo.variant != VariantCourier && /* [HGM] */
777 board[rf-2][ff] == EmptySquare) {
778 callback(board, flags, NormalMove,
779 rf, ff, rf-2, ff, closure);
781 for (s = -1; s <= 1; s += 2) {
782 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
783 ((flags & F_KRIEGSPIEL_CAPTURE) ||
784 WhitePiece(board[rf - 1][ff + s]))) {
785 callback(board, flags,
786 rf <= promoRank ? BlackPromotion : NormalMove,
787 rf, ff, rf - 1, ff + s, closure);
789 if (rf < BOARD_HEIGHT>>1) {
790 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
791 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
792 board[rf][ff + s] == WhitePawn &&
793 board[rf-1][ff + s] == EmptySquare) {
794 callback(board, flags, BlackCapturesEnPassant,
795 rf, ff, rf-1, ff + s, closure);
805 for (i = -1; i <= 1; i += 2)
806 for (j = -1; j <= 1; j += 2)
807 for (s = 1; s <= 2; s++) {
810 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
811 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
812 && !SameColor(board[rf][ff], board[rt][ft]))
813 callback(board, flags, NormalMove,
814 rf, ff, rt, ft, closure);
818 case SHOGI WhiteKnight:
819 for (s = -1; s <= 1; s += 2) {
820 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
821 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
822 callback(board, flags, NormalMove,
823 rf, ff, rf + 2, ff + s, closure);
828 case SHOGI BlackKnight:
829 for (s = -1; s <= 1; s += 2) {
830 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
831 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
832 callback(board, flags, NormalMove,
833 rf, ff, rf - 2, ff + s, closure);
840 for (d = 0; d <= 1; d++)
841 for (s = -1; s <= 1; s += 2) {
844 rt = rf + (i * s) * d;
845 ft = ff + (i * s) * (1 - d);
846 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
847 if (m == 0 && board[rt][ft] == EmptySquare)
848 callback(board, flags, NormalMove,
849 rf, ff, rt, ft, closure);
850 if (m == 1 && board[rt][ft] != EmptySquare &&
851 !SameColor(board[rf][ff], board[rt][ft]) )
852 callback(board, flags, NormalMove,
853 rf, ff, rt, ft, closure);
854 if (board[rt][ft] != EmptySquare && m++) break;
859 /* Gold General (and all its promoted versions) . First do the */
860 /* diagonal forward steps, then proceed as normal Wazir */
861 case SHOGI (PROMOTED WhitePawn):
862 if(gameInfo.variant == VariantShogi) goto WhiteGold;
863 case SHOGI (PROMOTED BlackPawn):
864 if(gameInfo.variant == VariantShogi) goto BlackGold;
865 SlideVertical(board, flags, rf, ff, callback, closure);
868 case SHOGI (PROMOTED WhiteKnight):
869 if(gameInfo.variant == VariantShogi) goto WhiteGold;
870 case SHOGI BlackDrunk:
871 case SHOGI BlackAlfil:
872 Ferz(board, flags, rf, ff, callback, closure);
873 StepSideways(board, flags, rf, ff, callback, closure);
874 StepBackward(board, flags, rf, ff, callback, closure);
877 case SHOGI (PROMOTED BlackKnight):
878 if(gameInfo.variant == VariantShogi) goto BlackGold;
879 case SHOGI WhiteDrunk:
880 case SHOGI WhiteAlfil:
881 Ferz(board, flags, rf, ff, callback, closure);
882 StepSideways(board, flags, rf, ff, callback, closure);
883 StepForward(board, flags, rf, ff, callback, closure);
887 case SHOGI WhiteStag:
888 case SHOGI BlackStag:
889 if(gameInfo.variant == VariantShogi) goto BlackGold;
890 SlideVertical(board, flags, rf, ff, callback, closure);
891 Ferz(board, flags, rf, ff, callback, closure);
892 StepSideways(board, flags, rf, ff, callback, closure);
895 case SHOGI (PROMOTED WhiteQueen):
896 case SHOGI WhiteTokin:
897 case SHOGI WhiteWazir:
899 StepDiagForward(board, flags, rf, ff, callback, closure);
900 Wazir(board, flags, rf, ff, callback, closure);
903 case SHOGI (PROMOTED BlackQueen):
904 case SHOGI BlackTokin:
905 case SHOGI BlackWazir:
907 StepDiagBackward(board, flags, rf, ff, callback, closure);
908 Wazir(board, flags, rf, ff, callback, closure);
913 Wazir(board, flags, rf, ff, callback, closure);
916 case SHOGI WhiteMarshall:
917 case SHOGI BlackMarshall:
918 Ferz(board, flags, rf, ff, callback, closure);
919 for (d = 0; d <= 1; d++)
920 for (s = -2; s <= 2; s += 4) {
922 ft = ff + s * (1 - d);
923 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
924 if (!SameColor(board[rf][ff], board[rt][ft]) )
925 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
929 case SHOGI WhiteAngel:
930 case SHOGI BlackAngel:
931 Wazir(board, flags, rf, ff, callback, closure);
935 /* [HGM] support Shatranj pieces */
936 for (rs = -1; rs <= 1; rs += 2)
937 for (fs = -1; fs <= 1; fs += 2) {
940 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
941 && ( gameInfo.variant != VariantXiangqi ||
942 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
944 && !SameColor(board[rf][ff], board[rt][ft]))
945 callback(board, flags, NormalMove,
946 rf, ff, rt, ft, closure);
947 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
948 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
949 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
951 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
952 && !SameColor(board[rf][ff], board[rt][ft]))
953 callback(board, flags, NormalMove,
954 rf, ff, rt, ft, closure);
956 if(gameInfo.variant == VariantSpartan)
957 for(fs = -1; fs <= 1; fs += 2) {
959 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
960 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
964 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
967 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
968 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
969 for (s = -2; s <= 2; s += 4) {
971 ft = ff + s * (1 - d);
972 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
973 if (SameColor(board[rf][ff], board[rt][ft])) continue;
974 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
977 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
978 case SHOGI WhiteCardinal:
979 case SHOGI BlackCardinal:
980 case SHOGI WhitePCardinal:
981 case SHOGI BlackPCardinal:
983 Bishop(board, flags, rf, ff, callback, closure);
984 Wazir(board, flags, rf, ff, callback, closure);
987 /* Capablanca Archbishop continues as Knight */
990 Knight(board, flags, rf, ff, callback, closure);
992 /* Shogi Bishops are ordinary Bishops */
993 case SHOGI WhiteBishop:
994 case SHOGI BlackBishop:
995 case SHOGI WhitePBishop:
996 case SHOGI BlackPBishop:
999 Bishop(board, flags, rf, ff, callback, closure);
1002 /* Shogi Lance is unlike anything, and asymmetric at that */
1003 case SHOGI WhiteQueen:
1004 if(gameInfo.variant == VariantChu) goto doQueen;
1008 if (rt >= BOARD_HEIGHT) break;
1009 if (SameColor(board[rf][ff], board[rt][ft])) break;
1010 callback(board, flags, NormalMove,
1011 rf, ff, rt, ft, closure);
1012 if (board[rt][ft] != EmptySquare) break;
1016 case SHOGI BlackQueen:
1017 if(gameInfo.variant == VariantChu) goto doQueen;
1022 if (SameColor(board[rf][ff], board[rt][ft])) break;
1023 callback(board, flags, NormalMove,
1024 rf, ff, rt, ft, closure);
1025 if (board[rt][ft] != EmptySquare) break;
1029 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1032 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1033 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1034 for (s = -2; s <= 2; s += 4) {
1036 ft = ff + s * (1 - d);
1037 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1038 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1039 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1040 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1042 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1043 Wazir(board, flags, rf, ff, callback, closure);
1045 Rook(board, flags, rf, ff, callback, closure);
1048 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1049 case SHOGI WhiteDragon:
1050 case SHOGI BlackDragon:
1051 case SHOGI WhitePDragon:
1052 case SHOGI BlackPDragon:
1054 Rook(board, flags, rf, ff, callback, closure);
1055 Ferz(board, flags, rf, ff, callback, closure);
1059 /* Capablanca Chancellor sets flag to continue as Knight */
1062 Rook(board, flags, rf, ff, callback, closure);
1063 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1064 Ferz(board, flags, rf, ff, callback, closure);
1066 Knight(board, flags, rf, ff, callback, closure);
1069 /* Shogi Rooks are ordinary Rooks */
1070 case SHOGI WhiteRook:
1071 case SHOGI BlackRook:
1072 case SHOGI WhitePRook:
1073 case SHOGI BlackPRook:
1076 Rook(board, flags, rf, ff, callback, closure);
1081 case SHOGI WhiteMother:
1082 case SHOGI BlackMother:
1084 Rook(board, flags, rf, ff, callback, closure);
1085 Bishop(board, flags, rf, ff, callback, closure);
1088 case SHOGI WhitePawn:
1089 StepForward(board, flags, rf, ff, callback, closure);
1092 case SHOGI BlackPawn:
1093 StepBackward(board, flags, rf, ff, callback, closure);
1097 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1098 case SHOGI WhiteFerz:
1099 Ferz(board, flags, rf, ff, callback, closure);
1100 StepForward(board, flags, rf, ff, callback, closure);
1104 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1105 case SHOGI BlackFerz:
1106 StepBackward(board, flags, rf, ff, callback, closure);
1110 /* [HGM] support Shatranj pieces */
1111 Ferz(board, flags, rf, ff, callback, closure);
1116 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1119 case SHOGI WhiteMonarch:
1120 case SHOGI BlackMonarch:
1121 case SHOGI WhiteKing:
1122 case SHOGI BlackKing:
1125 Ferz(board, flags, rf, ff, callback, closure);
1126 Wazir(board, flags, rf, ff, callback, closure);
1129 case WhiteNightrider:
1130 case BlackNightrider:
1131 for (i = -1; i <= 1; i += 2)
1132 for (j = -1; j <= 1; j += 2)
1133 for (s = 1; s <= 2; s++) { int k;
1136 ft = ff + k*j*(3-s);
1137 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1138 if (SameColor(board[rf][ff], board[rt][ft])) break;
1139 callback(board, flags, NormalMove,
1140 rf, ff, rt, ft, closure);
1141 if (board[rt][ft] != EmptySquare) break;
1147 Bishop(board, flags, rf, ff, callback, closure);
1148 Rook(board, flags, rf, ff, callback, closure);
1149 Knight(board, flags, rf, ff, callback, closure);
1152 // Use Lance as Berolina / Spartan Pawn.
1154 if(gameInfo.variant == VariantSuper) goto Amazon;
1155 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1156 callback(board, flags,
1157 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1158 rf, ff, rf + 1, ff, closure);
1159 for (s = -1; s <= 1; s += 2) {
1160 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1161 callback(board, flags,
1162 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1163 rf, ff, rf + 1, ff + s, closure);
1164 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1165 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1170 if(gameInfo.variant == VariantSuper) goto Amazon;
1171 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1172 callback(board, flags,
1173 rf <= promoRank ? BlackPromotion : NormalMove,
1174 rf, ff, rf - 1, ff, closure);
1175 for (s = -1; s <= 1; s += 2) {
1176 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1177 callback(board, flags,
1178 rf <= promoRank ? BlackPromotion : NormalMove,
1179 rf, ff, rf - 1, ff + s, closure);
1180 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1181 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1185 case SHOGI WhiteNothing:
1186 case SHOGI BlackNothing:
1187 case SHOGI WhiteLion:
1188 case SHOGI BlackLion:
1191 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1192 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1193 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1194 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1195 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1196 rf, ff, rt, ft, closure);
1201 case SHOGI WhiteFalcon:
1202 case SHOGI BlackFalcon:
1203 case SHOGI WhitePDagger:
1204 case SHOGI BlackPDagger:
1205 SlideSideways(board, flags, rf, ff, callback, closure);
1206 StepVertical(board, flags, rf, ff, callback, closure);
1209 case SHOGI WhiteCobra:
1210 case SHOGI BlackCobra:
1211 StepVertical(board, flags, rf, ff, callback, closure);
1214 case SHOGI (PROMOTED WhiteFerz):
1215 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1216 case SHOGI (PROMOTED BlackFerz):
1217 if(gameInfo.variant == VariantShogi) goto BlackGold;
1218 case SHOGI WhitePSword:
1219 case SHOGI BlackPSword:
1220 SlideVertical(board, flags, rf, ff, callback, closure);
1221 StepSideways(board, flags, rf, ff, callback, closure);
1224 case SHOGI WhiteUnicorn:
1225 case SHOGI BlackUnicorn:
1226 Ferz(board, flags, rf, ff, callback, closure);
1227 StepVertical(board, flags, rf, ff, callback, closure);
1230 case SHOGI WhiteMan:
1231 StepDiagForward(board, flags, rf, ff, callback, closure);
1232 StepVertical(board, flags, rf, ff, callback, closure);
1235 case SHOGI BlackMan:
1236 StepDiagBackward(board, flags, rf, ff, callback, closure);
1237 StepVertical(board, flags, rf, ff, callback, closure);
1240 case SHOGI WhiteHCrown:
1241 case SHOGI BlackHCrown:
1242 Bishop(board, flags, rf, ff, callback, closure);
1243 SlideSideways(board, flags, rf, ff, callback, closure);
1246 case SHOGI WhiteCrown:
1247 case SHOGI BlackCrown:
1248 Bishop(board, flags, rf, ff, callback, closure);
1249 SlideVertical(board, flags, rf, ff, callback, closure);
1252 case SHOGI WhiteHorned:
1253 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1254 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1255 if(killX >= 0) break;
1256 Bishop(board, flags, rf, ff, callback, closure);
1257 SlideSideways(board, flags, rf, ff, callback, closure);
1258 SlideBackward(board, flags, rf, ff, callback, closure);
1261 case SHOGI BlackHorned:
1262 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1263 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1264 if(killX >= 0) break;
1265 Bishop(board, flags, rf, ff, callback, closure);
1266 SlideSideways(board, flags, rf, ff, callback, closure);
1267 SlideForward(board, flags, rf, ff, callback, closure);
1270 case SHOGI WhiteEagle:
1271 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1272 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1273 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1274 if(killX >= 0) break;
1275 Rook(board, flags, rf, ff, callback, closure);
1276 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1279 case SHOGI BlackEagle:
1280 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1281 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1282 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1283 if(killX >= 0) break;
1284 Rook(board, flags, rf, ff, callback, closure);
1285 SlideDiagForward(board, flags, rf, ff, callback, closure);
1288 case SHOGI WhiteDolphin:
1289 case SHOGI BlackHorse:
1290 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1291 SlideVertical(board, flags, rf, ff, callback, closure);
1294 case SHOGI BlackDolphin:
1295 case SHOGI WhiteHorse:
1296 SlideDiagForward(board, flags, rf, ff, callback, closure);
1297 SlideVertical(board, flags, rf, ff, callback, closure);
1300 case SHOGI WhiteLance:
1301 SlideForward(board, flags, rf, ff, callback, closure);
1304 case SHOGI BlackLance:
1305 SlideBackward(board, flags, rf, ff, callback, closure);
1308 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1312 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1325 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1326 Board xqCheckers, nullBoard;
1328 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1329 int rf, int ff, int rt, int ft,
1333 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1335 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1337 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1339 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1341 if (!(flags & F_IGNORE_CHECK) ) {
1342 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1345 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1346 kings += (board[r][f] == BlackKing);
1350 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1352 check = CheckTest(board, flags, rf, ff, rt, ft,
1353 kind == WhiteCapturesEnPassant ||
1354 kind == BlackCapturesEnPassant);
1355 if(promo) board[rf][ff] = BlackLance;
1358 if (flags & F_ATOMIC_CAPTURE) {
1359 if (board[rt][ft] != EmptySquare ||
1360 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1362 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1363 if (board[rf][ff] == king) return;
1364 for (r = rt-1; r <= rt+1; r++) {
1365 for (f = ft-1; f <= ft+1; f++) {
1366 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1367 board[r][f] == king) return;
1372 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1379 int captures; // [HGM] losers
1380 } LegalityTestClosure;
1383 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1384 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1385 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1386 moves that would destroy your own king. The CASTLE_OK flags are
1387 true if castling is not yet ruled out by a move of the king or
1388 rook. Return TRUE if the player on move is currently in check and
1389 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1391 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1394 int ff, ft, k, left, right, swap;
1395 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1396 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1397 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1402 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1403 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1404 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1406 if (inCheck) return TRUE;
1408 /* Generate castling moves */
1409 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1410 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1413 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1414 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1416 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1417 if ((flags & F_WHITE_ON_MOVE) &&
1418 (flags & F_WHITE_KCASTLE_OK) &&
1419 board[0][ff] == wKing &&
1420 board[0][ff + 1] == EmptySquare &&
1421 board[0][ff + 2] == EmptySquare &&
1422 board[0][BOARD_RGHT-3] == EmptySquare &&
1423 board[0][BOARD_RGHT-2] == EmptySquare &&
1424 board[0][BOARD_RGHT-1] == WhiteRook &&
1425 castlingRights[0] != NoRights && /* [HGM] check rights */
1426 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1428 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1429 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1430 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1431 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1433 callback(board, flags,
1434 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1435 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1437 if ((flags & F_WHITE_ON_MOVE) &&
1438 (flags & F_WHITE_QCASTLE_OK) &&
1439 board[0][ff] == wKing &&
1440 board[0][ff - 1] == EmptySquare &&
1441 board[0][ff - 2] == EmptySquare &&
1442 board[0][BOARD_LEFT+2] == EmptySquare &&
1443 board[0][BOARD_LEFT+1] == EmptySquare &&
1444 board[0][BOARD_LEFT+0] == WhiteRook &&
1445 castlingRights[1] != NoRights && /* [HGM] check rights */
1446 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1448 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1449 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1450 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1452 callback(board, flags,
1453 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1454 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1456 if (!(flags & F_WHITE_ON_MOVE) &&
1457 (flags & F_BLACK_KCASTLE_OK) &&
1458 board[BOARD_HEIGHT-1][ff] == bKing &&
1459 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1460 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1461 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1462 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1463 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1464 castlingRights[3] != NoRights && /* [HGM] check rights */
1465 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1467 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1468 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1469 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1470 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1472 callback(board, flags,
1473 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1474 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1476 if (!(flags & F_WHITE_ON_MOVE) &&
1477 (flags & F_BLACK_QCASTLE_OK) &&
1478 board[BOARD_HEIGHT-1][ff] == bKing &&
1479 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1480 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1481 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1482 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1483 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1484 castlingRights[4] != NoRights && /* [HGM] check rights */
1485 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1487 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1488 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1489 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1491 callback(board, flags,
1492 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1493 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1497 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1499 /* generate all potential FRC castling moves (KxR), ignoring flags */
1500 /* [HGM] test if the Rooks we find have castling rights */
1501 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1504 if ((flags & F_WHITE_ON_MOVE) != 0) {
1505 ff = castlingRights[2]; /* King file if we have any rights */
1506 if(ff != NoRights && board[0][ff] == WhiteKing) {
1507 if (appData.debugMode) {
1508 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1509 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1511 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1513 right = BOARD_RGHT-2;
1514 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1515 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1516 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1517 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1518 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1519 if(ft != NoRights && board[0][ft] == WhiteRook) {
1520 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1521 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1524 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1525 left = BOARD_LEFT+2;
1527 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1528 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1529 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1530 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1531 if(ff > BOARD_LEFT+2)
1532 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1533 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1534 if(ft != NoRights && board[0][ft] == WhiteRook) {
1535 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1536 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1540 ff = castlingRights[5]; /* King file if we have any rights */
1541 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1542 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1544 right = BOARD_RGHT-2;
1545 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1546 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1547 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1548 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1549 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1550 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1551 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1552 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1555 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1556 left = BOARD_LEFT+2;
1558 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1559 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1560 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1561 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1562 if(ff > BOARD_LEFT+2)
1563 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1564 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1565 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1566 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1567 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1584 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1585 int rf, int ff, int rt, int ft,
1590 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1592 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1594 if (rt == cl->rking && ft == cl->fking) {
1595 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1597 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1599 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1600 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1601 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1605 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1606 he leave himself in check? Or if rf == -1, is the player on move
1607 in check now? enPassant must be TRUE if the indicated move is an
1608 e.p. capture. The possibility of castling out of a check along the
1609 back rank is not accounted for (i.e., we still return nonzero), as
1610 this is illegal anyway. Return value is the number of times the
1611 king is in check. */
1613 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1615 CheckTestClosure cl;
1616 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1617 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1618 int saveKill = killX;
1619 /* Suppress warnings on uninitialized variables */
1621 if(gameInfo.variant == VariantXiangqi)
1622 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1623 if(gameInfo.variant == VariantKnightmate)
1624 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1625 if(gameInfo.variant == VariantChu || gameInfo.variant == VariantShogi) { // strictly speaking this is not needed, as Chu officially has no check
1626 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1627 if(gameInfo.variant == VariantShogi) prince -= 11; // White/BlackFalcon
1628 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1629 if(board[r][f] == k || board[r][f] == prince) {
1630 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1631 king = board[r][f]; // remember hich one we had
1638 captured = board[rf][ft];
1639 board[rf][ft] = EmptySquare;
1641 captured = board[rt][ft];
1642 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; }
1644 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1645 board[rt][ft] = board[rf][ff];
1646 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1648 ep = board[EP_STATUS];
1649 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1650 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1651 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1652 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1653 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1654 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1658 /* For compatibility with ICS wild 9, we scan the board in the
1659 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1660 and we test only whether that one is in check. */
1661 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1662 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1663 if (board[cl.rking][cl.fking] == king) {
1665 if(gameInfo.variant == VariantXiangqi) {
1666 /* [HGM] In Xiangqi opposing Kings means check as well */
1668 dir = (king >= BlackPawn) ? -1 : 1;
1669 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1670 board[i][cl.fking] == EmptySquare; i+=dir );
1671 if(i>=0 && i<BOARD_HEIGHT &&
1672 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1675 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1676 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1677 goto undo_move; /* 2-level break */
1684 if(rf != DROP_RANK) // [HGM] drop
1685 board[rf][ff] = board[rt][ft];
1687 board[rf][ft] = captured;
1688 board[rt][ft] = EmptySquare;
1690 if(saveKill >= 0) board[killY][killX] = trampled, killX = saveKill;
1691 board[rt][ft] = captured;
1693 board[EP_STATUS] = ep;
1696 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1700 HasLion (Board board, int flags)
1702 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1704 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1705 if(board[r][f] == lion) return 1;
1710 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1711 { // [HGM] put drop legality testing in separate routine for clarity
1713 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1714 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1715 n = PieceToNumber(piece);
1716 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1717 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1718 return ImpossibleMove; // piece not available
1719 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1720 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1721 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1722 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1723 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1724 if(piece == WhitePawn || piece == BlackPawn) {
1725 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1726 for(r=1; r<BOARD_HEIGHT-1; r++)
1727 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1728 // should still test if we mate with this Pawn
1730 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1731 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1733 if( (piece == WhitePawn || piece == BlackPawn) &&
1734 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1735 return IllegalMove; /* no pawn drops on 1st/8th */
1737 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1738 if (!(flags & F_IGNORE_CHECK) &&
1739 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1740 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1743 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1744 int rf, int ff, int rt, int ft,
1748 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1750 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1752 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1753 cl->captures++; // [HGM] losers: count legal captures
1754 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1759 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1761 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1763 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1764 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1765 piece = filterPiece = board[rf][ff];
1766 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1768 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1769 /* (perhaps we should disallow moves that obviously leave us in check?) */
1770 if((piece == WhiteFalcon || piece == BlackFalcon ||
1771 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1772 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1776 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1777 cl.ft = fFilter = ft;
1778 cl.kind = IllegalMove;
1779 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1780 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1781 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1782 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1783 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1784 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1786 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1787 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1788 if(board[rf][ff] < BlackPawn) { // white
1789 if(rf != 0) return IllegalMove; // must be on back rank
1790 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1791 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1792 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1793 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1795 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1796 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1797 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1798 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1799 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1802 if(gameInfo.variant == VariantChu) {
1803 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1804 if(promoChar != '+')
1805 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1806 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1807 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1809 if(gameInfo.variant == VariantShogi) {
1810 /* [HGM] Shogi promotions. '=' means defer */
1811 if(rf != DROP_RANK && cl.kind == NormalMove) {
1812 ChessSquare piece = board[rf][ff];
1814 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1815 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1816 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1817 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1818 promoChar = '+'; // allowed ICS notations
1819 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1820 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1821 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1822 else if(flags & F_WHITE_ON_MOVE) {
1823 if( (int) piece < (int) WhiteWazir &&
1824 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1825 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1826 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1827 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1828 else /* promotion optional, default is defer */
1829 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1830 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1832 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1833 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1834 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1835 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1836 else /* promotion optional, default is defer */
1837 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1838 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1842 if (promoChar != NULLCHAR) {
1843 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1844 ChessSquare piece = board[rf][ff];
1845 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1846 // should test if in zone, really
1847 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1849 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1851 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1852 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1853 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1854 if(piece == EmptySquare)
1855 cl.kind = ImpossibleMove; // non-existing piece
1856 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1857 cl.kind = IllegalMove; // no two Lions
1858 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1859 if(promoChar != PieceToChar(BlackKing)) {
1860 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1861 if(piece == BlackLance) cl.kind = ImpossibleMove;
1862 } else { // promotion to King allowed only if we do not have two yet
1863 int r, f, kings = 0;
1864 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1865 if(kings == 2) cl.kind = IllegalMove;
1867 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1868 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1869 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1870 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1871 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1872 cl.kind = IllegalMove; // promotion to King usually not allowed
1874 cl.kind = IllegalMove;
1884 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1885 int rf, int ff, int rt, int ft,
1889 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1891 register MateTestClosure *cl = (MateTestClosure *) closure;
1896 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1898 MateTest (Board board, int flags)
1901 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1902 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1904 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1905 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1906 nrKing += (board[r][f] == king); // stm has king
1907 if( board[r][f] != EmptySquare ) {
1908 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1913 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1914 case VariantShatranj:
1915 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1919 if(nrKing == 0) return MT_NOKING;
1922 if(myPieces == 1) return MT_BARE;
1925 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1926 // [HGM] 3check: yet to do!
1928 return inCheck ? MT_CHECK : MT_NONE;
1930 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1931 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1932 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1933 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1934 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1935 if(board[n][holdings] != EmptySquare) {
1936 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1937 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1940 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1941 return myPieces == hisPieces ? MT_STALEMATE :
1942 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1943 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1944 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1946 return inCheck ? MT_CHECKMATE
1947 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1948 MT_STAINMATE : MT_STALEMATE;
1953 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1954 int rf, int ff, int rt, int ft,
1958 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1960 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1961 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1963 // [HGM] wild: for wild-card pieces rt and rf are dummies
1964 if(piece == WhiteFalcon || piece == BlackFalcon ||
1965 piece == WhiteCobra || piece == BlackCobra)
1968 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1969 || PieceToChar(board[rf][ff]) == '~'
1970 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1972 (cl->rfIn == -1 || cl->rfIn == rf) &&
1973 (cl->ffIn == -1 || cl->ffIn == ff) &&
1974 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1975 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1977 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1980 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1981 // [HGM] oneclick: if multiple moves, be sure we remember capture
1982 cl->piece = board[rf][ff];
1985 cl->rt = wildCard ? cl->rtIn : rt;
1986 cl->ft = wildCard ? cl->ftIn : ft;
1989 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1994 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1996 int illegal = 0; char c = closure->promoCharIn;
1998 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1999 closure->count = closure->captures = 0;
2000 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2001 closure->kind = ImpossibleMove;
2002 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
2003 fFilter = closure->ftIn;
2004 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
2005 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2006 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
2007 closure->count = closure->captures = 0;
2008 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2009 closure->kind = ImpossibleMove;
2010 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2013 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2014 if (closure->count == 0) {
2015 /* See if it's an illegal move due to check */
2017 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2018 if (closure->count == 0) {
2019 /* No, it's not even that */
2020 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2021 int f, r; // if there is only a single piece of the requested type on the board, use that
2022 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2023 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2024 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2025 if(closure->count > 1) illegal = 0; // ambiguous
2027 if(closure->count == 0) {
2028 if (appData.debugMode) { int i, j;
2029 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2030 for(j=0; j<BOARD_WIDTH; j++)
2031 fprintf(debugFP, "%3d", (int) board[i][j]);
2032 fprintf(debugFP, "\n");
2038 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2039 DisambiguateClosure spare = *closure;
2040 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2041 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2042 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2046 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2047 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2048 if(closure->piece < BlackPawn) { // white
2049 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2050 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2051 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2052 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2053 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2055 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2056 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2057 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2058 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2059 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2062 if(gameInfo.variant == VariantChu) {
2063 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2065 if(gameInfo.variant == VariantShogi) {
2066 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2067 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2068 ChessSquare piece = closure->piece;
2069 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2070 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2071 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2072 c = '+'; // allowed ICS notations
2073 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2074 else if(flags & F_WHITE_ON_MOVE) {
2075 if( (int) piece < (int) WhiteWazir &&
2076 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2077 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2078 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2079 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2080 else /* promotion optional, default is defer */
2081 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2082 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2084 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2085 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2086 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2087 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2088 else /* promotion optional, default is defer */
2089 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2090 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2093 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2094 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2096 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2097 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2098 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2099 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2100 c = PieceToChar(BlackFerz);
2101 else if(gameInfo.variant == VariantGreat)
2102 c = PieceToChar(BlackMan);
2103 else if(gameInfo.variant == VariantGrand)
2104 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2106 c = PieceToChar(BlackQueen);
2107 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2108 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2109 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2110 ChessSquare p = closure->piece;
2111 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2112 closure->kind = ImpossibleMove; // used on non-promotable piece
2113 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2114 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2116 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2117 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2118 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2119 if (closure->count > 1) {
2120 closure->kind = AmbiguousMove;
2123 /* Note: If more than one illegal move matches, but no legal
2124 moves, we return IllegalMove, not AmbiguousMove. Caller
2125 can look at closure->count to detect this.
2127 closure->kind = IllegalMove;
2141 } CoordsToAlgebraicClosure;
2143 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2144 ChessMove kind, int rf, int ff,
2145 int rt, int ft, VOIDSTAR closure));
2148 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2150 register CoordsToAlgebraicClosure *cl =
2151 (CoordsToAlgebraicClosure *) closure;
2153 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2154 (board[rf][ff] == cl->piece
2155 || PieceToChar(board[rf][ff]) == '~' &&
2156 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2160 cl->kind = kind; /* this is the move we want */
2162 cl->file++; /* need file to rule out this move */
2166 cl->rank++; /* need rank to rule out this move */
2168 cl->either++; /* rank or file will rule out this move */
2174 /* Convert coordinates to normal algebraic notation.
2175 promoChar must be NULLCHAR or 'x' if not a promotion.
2178 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2182 char *outp = out, c, capture;
2183 CoordsToAlgebraicClosure cl;
2185 if (rf == DROP_RANK) {
2186 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2187 /* Bughouse piece drop */
2188 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2193 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2195 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2198 if (promoChar == 'x') promoChar = NULLCHAR;
2199 piece = board[rf][ff];
2200 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2205 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2206 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2207 /* Keep short notation if move is illegal only because it
2208 leaves the player in check, but still return IllegalMove */
2209 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2210 if (kind == IllegalMove) break;
2215 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2216 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2217 /* Non-capture; use style "e5" */
2220 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2222 /* Capture; use style "exd5" */
2224 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2228 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2230 /* Use promotion suffix style "=Q" */
2232 if (promoChar != NULLCHAR) {
2233 if(IS_SHOGI(gameInfo.variant)) {
2234 /* [HGM] ... but not in Shogi! */
2235 *outp++ = promoChar == '=' ? '=' : '+';
2238 *outp++ = ToUpper(promoChar);
2247 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2248 /* Code added by Tord: FRC castling. */
2249 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2250 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2252 safeStrCpy(out, "O-O", MOVE_LEN);
2254 safeStrCpy(out, "O-O-O", MOVE_LEN);
2255 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2257 /* End of code added by Tord */
2258 /* Test for castling or ICS wild castling */
2259 /* Use style "O-O" (oh-oh) for PGN compatibility */
2260 else if (rf == rt &&
2261 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2262 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2263 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2264 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2265 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2266 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2268 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2270 /* This notation is always unambiguous, unless there are
2271 kings on both the d and e files, with "wild castling"
2272 possible for the king on the d file and normal castling
2273 possible for the other. ICS rules for wild 9
2274 effectively make castling illegal for either king in
2275 this situation. So I am not going to worry about it;
2276 I'll just generate an ambiguous O-O in this case.
2278 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2281 /* else fall through */
2286 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2287 cl.ft = fFilter = ft;
2289 cl.kind = IllegalMove;
2290 cl.rank = cl.file = cl.either = 0;
2291 c = PieceToChar(piece) ;
2292 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2294 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2295 /* Generate pretty moves for moving into check, but
2296 still return IllegalMove.
2298 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2299 if (cl.kind == IllegalMove) break;
2300 cl.kind = IllegalMove;
2303 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2304 else "Ngf3" or "Ngxf7",
2305 else "N1f3" or "N5xf7",
2306 else "Ng1f3" or "Ng5xf7".
2308 if( c == '~' || c == '+') {
2309 /* [HGM] print nonexistent piece as its demoted version */
2310 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2312 if(c=='+') *outp++ = c;
2313 *outp++ = ToUpper(PieceToChar(piece));
2315 if (cl.file || (cl.either && !cl.rank)) {
2321 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2324 if(board[rt][ft] != EmptySquare)
2330 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2331 if (IS_SHOGI(gameInfo.variant)) {
2332 /* [HGM] in Shogi non-pawns can promote */
2333 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2335 else if (gameInfo.variant == VariantChuChess && promoChar ||
2336 gameInfo.variant != VariantSuper && promoChar &&
2337 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2339 *outp++ = ToUpper(promoChar);
2341 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2343 *outp++ = ToUpper(promoChar);
2349 /* Moving a nonexistent piece */
2353 /* Not a legal move, even ignoring check.
2354 If there was a piece on the from square,
2355 use style "Ng1g3" or "Ng1xe8";
2356 if there was a pawn or nothing (!),
2357 use style "g1g3" or "g1xe8". Use "x"
2358 if a piece was on the to square, even
2359 a piece of the same color.
2363 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2365 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2366 c += (board[r][f] == piece); // count on-board pieces of given type
2367 *outp++ = ToUpper(PieceToChar(piece));
2369 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2373 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2375 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2379 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2380 /* Use promotion suffix style "=Q" */
2381 if (promoChar != NULLCHAR && promoChar != 'x') {
2383 *outp++ = ToUpper(promoChar);
2390 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2399 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2401 int preyStackPointer, chaseStackPointer;
2404 unsigned char rf, ff, rt, ft;
2408 unsigned char rank, file;
2414 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2416 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2417 int rf, int ff, int rt, int ft,
2421 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2422 { // For adding captures that can lead to chase indictment to the chaseStack
2423 if(board[rt][ft] == EmptySquare) return; // non-capture
2424 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2425 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2426 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2427 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2428 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2429 chaseStack[chaseStackPointer].rf = rf;
2430 chaseStack[chaseStackPointer].ff = ff;
2431 chaseStack[chaseStackPointer].rt = rt;
2432 chaseStack[chaseStackPointer].ft = ft;
2433 chaseStackPointer++;
2436 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2437 int rf, int ff, int rt, int ft,
2441 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2442 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2444 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2446 if(board[rt][ft] == EmptySquare) return; // no capture
2447 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2448 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2450 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2451 for(i=0; i<chaseStackPointer; i++) {
2452 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2453 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2454 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2455 chaseStack[i] = chaseStack[--chaseStackPointer];
2461 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2462 int rf, int ff, int rt, int ft,
2466 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2467 { // for determining if a piece (given through the closure) is protected
2468 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2470 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2471 if(appData.debugMode && board[rt][ft] != EmptySquare)
2472 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2475 extern char moveList[MAX_MOVES][MOVE_LEN];
2478 PerpetualChase (int first, int last)
2479 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2482 ChessSquare captured;
2484 preyStackPointer = 0; // clear stack of chased pieces
2485 for(i=first; i<last; i+=2) { // for all positions with same side to move
2486 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2487 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2488 // determine all captures possible after the move, and put them on chaseStack
2489 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2490 if(appData.debugMode) { int n;
2491 for(n=0; n<chaseStackPointer; n++)
2492 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2493 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2494 fprintf(debugFP, ": all capts\n");
2496 // determine all captures possible before the move, and delete them from chaseStack
2497 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2498 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2499 cl.rt = moveList[i][3]-ONE;
2500 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2501 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2502 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2503 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2504 if(appData.debugMode) { int n;
2505 for(n=0; n<chaseStackPointer; n++)
2506 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2507 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2508 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2510 // chaseSack now contains all captures made possible by the move
2511 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2512 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2513 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2515 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2516 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2518 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2519 continue; // C or H attack on R is always chase; leave on chaseStack
2521 if(attacker == victim) {
2522 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2523 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2524 // we can capture back with equal piece, so this is no chase but a sacrifice
2525 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2526 j--; /* ! */ continue;
2531 // the attack is on a lower piece, or on a pinned or blocked equal one
2532 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2533 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2534 // test if the victim is protected by a true protector. First make the capture.
2535 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2536 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2537 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2538 // Then test if the opponent can recapture
2539 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2540 cl.rt = chaseStack[j].rt;
2541 cl.ft = chaseStack[j].ft;
2542 if(appData.debugMode) {
2543 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2545 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2546 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2547 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2548 // unmake the capture
2549 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2550 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2551 // if a recapture was found, piece is protected, and we are not chasing it.
2552 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2553 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2557 // chaseStack now contains all moves that chased
2558 if(appData.debugMode) { int n;
2559 for(n=0; n<chaseStackPointer; n++)
2560 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2561 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2562 fprintf(debugFP, ": chases\n");
2564 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2565 for(j=0; j<chaseStackPointer; j++) {
2566 preyStack[j].rank = chaseStack[j].rt;
2567 preyStack[j].file = chaseStack[j].ft;
2569 preyStackPointer = chaseStackPointer;
2572 for(j=0; j<chaseStackPointer; j++) {
2573 for(k=0; k<preyStackPointer; k++) {
2574 // search the victim of each chase move on the preyStack (first occurrence)
2575 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2576 if(k < tail) break; // piece was already identified as still being chased
2577 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2578 preyStack[tail] = preyStack[k]; // by swapping
2579 preyStack[k] = preyStack[preyStackPointer];
2585 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2586 if(appData.debugMode) { int n;
2587 for(n=0; n<preyStackPointer; n++)
2588 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2589 fprintf(debugFP, "always chased upto ply %d\n", i);
2591 // now adjust the location of the chased pieces according to opponent move
2592 for(j=0; j<preyStackPointer; j++) {
2593 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2594 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2595 preyStack[j].rank = moveList[i+1][3]-ONE;
2596 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2601 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2602 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the