2 * moves.c - Move generation and checking
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.
10 * Enhancements Copyright 2005 Alessandro Scotti
12 * The following terms apply to Digital Equipment Corporation's copyright
14 * ------------------------------------------------------------------------
17 * Permission to use, copy, modify, and distribute this software and its
18 * documentation for any purpose and without fee is hereby granted,
19 * provided that the above copyright notice appear in all copies and that
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
61 #else /* not HAVE_STRING_H */
63 #endif /* not HAVE_STRING_H */
69 int WhitePiece P((ChessSquare));
70 int BlackPiece P((ChessSquare));
71 int SameColor P((ChessSquare, ChessSquare));
72 int PosFlags(int index);
74 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
76 char *pieceDesc[EmptySquare];
77 char *defaultDesc[EmptySquare] = {
78 "fmWfceFifmnD", "N", "B", "R", "Q",
79 "F", "A", "BN", "RN", "W", "K",
80 "mRcpR", "N0", "BW", "RF", "gQ",
81 "", "", "QN", "", "N", "",
83 "", "", "", "", "", "",
85 "", "", "", "", "", "K"
89 WhitePiece (ChessSquare piece)
91 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
95 BlackPiece (ChessSquare piece)
97 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
102 SameColor (ChessSquare piece1, ChessSquare piece2)
104 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
105 (int) piece1 < (int) BlackPawn &&
106 (int) piece2 >= (int) WhitePawn &&
107 (int) piece2 < (int) BlackPawn)
108 || ((int) piece1 >= (int) BlackPawn &&
109 (int) piece1 < (int) EmptySquare &&
110 (int) piece2 >= (int) BlackPawn &&
111 (int) piece2 < (int) EmptySquare);
114 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
117 char pieceToChar[] = {
118 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
119 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
120 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
121 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
123 char pieceNickName[EmptySquare];
126 PieceToChar (ChessSquare p)
128 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
129 return pieceToChar[(int) p];
133 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
136 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
138 while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
146 if(c == '.') return EmptySquare;
147 for(i=0; i< (int) EmptySquare; i++)
148 if(pieceNickName[i] == c) return (ChessSquare) i;
149 for(i=0; i< (int) EmptySquare; i++)
150 if(pieceToChar[i] == c) return (ChessSquare) i;
155 CopyBoard (Board to, Board from)
159 for (i = 0; i < BOARD_HEIGHT; i++)
160 for (j = 0; j < BOARD_WIDTH; j++)
161 to[i][j] = from[i][j];
162 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
163 to[VIRGIN][j] = from[VIRGIN][j],
164 to[CASTLING][j] = from[CASTLING][j];
165 to[HOLDINGS_SET] = 0; // flag used in ICS play
169 CompareBoards (Board board1, Board board2)
173 for (i = 0; i < BOARD_HEIGHT; i++)
174 for (j = 0; j < BOARD_WIDTH; j++) {
175 if (board1[i][j] != board2[i][j])
181 char defaultName[] = "PNBRQ......................................K" // white
182 "pnbrq......................................k"; // black
183 char shogiName[] = "PNBRLS...G.++++++..........................K" // white
184 "pnbrls...g.++++++..........................k"; // black
185 char xqName[] = "PH.R.AE..K.C................................" // white
186 "ph.r.ae..k.c................................"; // black
189 CollectPieceDescriptors ()
190 { // make a line of piece descriptions for use in the PGN Piece tag:
191 // dump all engine defined pieces, and pieces with non-standard names,
192 // but suppress black pieces that are the same as their white counterpart
194 static char buf[MSG_SIZ];
195 char *m, c, d, *pieceName = defaultName;
198 if(!pieceDefs) return "";
199 if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
200 if(gameInfo.variant == VariantShogi) pieceName = shogiName;
201 if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
202 for(p=WhitePawn; p<EmptySquare; p++) {
203 if((c = pieceToChar[p]) == '.' || c == '~') continue; // does not participate
204 m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED p] : c);
205 if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == toupper(c)
206 && (c != '+' || pieceToChar[DEMOTED BLACK_TO_WHITE p] == d)) { // black member of normal pair
207 char *wm = pieceDesc[BLACK_TO_WHITE p];
208 if(!m && !wm || m && wm && !strcmp(wm, m)) continue; // moves as a white piece
209 } else // white or unpaired black
210 if((p < BlackPawn || CharToPiece(toupper(d)) != EmptySquare) && // white or lone black
211 !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
212 // TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
213 if(!m) m = defaultDesc[p];
215 snprintf(buf+len, MSG_SIZ-len, "%s%s%c:%s", len ? ";" : "", c == '+' ? "+" : "", d, m);
220 // [HGM] gen: configurable move generation from Betza notation sent by engine.
221 // Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
222 // square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
223 // if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
224 // target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
225 // is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
226 // user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
227 // generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
228 // can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
229 // 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
233 // alphabet "abcdefghijklmnopqrstuvwxyz"
234 char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
235 char xStep[] = "2110.130.102.10.00....0..2";
236 char yStep[] = "2132.133.313.20.11....1..3";
237 char dirType[] = "01000104000200000260050000";
238 char upgrade[] = "AFCD.BGH.JQL.NO.KW....R..Z";
239 char rotate[] = "DRCA.WHG.JKL.NO.QB....F..Z";
241 // alphabet "a b c d e f g h i j k l m n o p q r s t u v w x y z "
242 int dirs1[] = { 0,0x3C,0,0,0,0xC3,0,0, 0,0,0,0xF0,0,0,0,0,0,0x0F,0 ,0,0,0 ,0,0,0,0 };
243 int dirs2[] = { 0,0x18,0,0,0,0x81,0,0xFF,0,0,0,0x60,0,0,0,0,0,0x06,0x66,0,0,0x99,0,0,0,0 };
244 int dirs3[] = { 0,0x38,0,0,0,0x83,0,0xFF,0,0,0,0xE0,0,0,0,0,0,0x0E,0xEE,0,0,0xBB,0,0,0,0 };
245 int dirs4[] = { 0,0x10,0,0,0,0x01,0,0xFF,0,0,0,0x40,0,0,0,0,0,0x04,0x44,0,0,0x11,0,0,0,0 };
247 int rot[][4] = { // rotation matrices for each direction
259 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
265 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
267 char buf[80], *p = desc, *atom = NULL;
268 int mine, his, dir, bit, occup, i;
269 if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
270 while(*p) { // more moves to go
271 int expo = 1, dx, dy, x, y, mode, dirSet, ds2, retry=0, initial=0, jump=1, skip = 0, all = 0;
273 if(*p == 'i') initial = 1, desc = ++p;
274 while(islower(*p)) p++; // skip prefixes
275 if(!isupper(*p)) return; // syntax error: no atom
276 dx = xStep[*p-'A'] - '0';// step vector of atom
277 dy = yStep[*p-'A'] - '0';
278 dirSet = 0; // build direction set based on atom symmetry
279 switch(symmetry[*p-'A']) {
280 case 'B': expo = 0; // bishop, slide
281 case 'F': all = 0xAA; // diagonal atom (degenerate 4-fold)
282 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
283 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
284 int b = dirs1[*desc-'a']; // use wide version
285 if( islower(desc[1]) &&
286 ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim)
287 b = dirs1[*desc-'a'] & dirs1[desc[1]-'a']; // intersect wide & perp wide
292 dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
294 case 'R': expo = 0; // rook, slide
295 case 'W': all = 0x55; // orthogonal atom (non-deg 4-fold)
296 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
297 while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
298 dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
299 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
301 case 'N': all = 0xFF; // oblique atom (degenerate 8-fold)
302 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
303 if(*desc == 'h') { // chiral direction sets 'hr' and 'hl'
304 dirSet = (desc[1] == 'r' ? 0x55 : 0xAA); desc += 2;
306 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
307 int b = dirs2[*desc-'a']; // when alone, use narrow version
308 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
309 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
310 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
311 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
316 if(!dirSet) dirSet = 0xFF;
318 case 'Q': expo = 0; // queen, slide
319 case 'K': all = 0xFF; // non-deg (pseudo) 8-fold
321 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
322 int b = dirs4[*desc-'a']; // when alone, use narrow version
323 if(desc[1] == *desc) desc++; // doubling forces alone
324 else if(islower(desc[1]) && i < '4'
325 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
326 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
331 if(!dirSet) dirSet = (tx < 0 ? 0xFF // default is all directions, but in continuation leg
332 : all == 0xFF ? 0xEF : 0x45); // omits backward, and for 4-fold atoms also diags
333 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
334 ds2 = dirSet & 0xAA; // extract diagonal directions
335 if(dirSet &= 0x55) // start with orthogonal moves, if present
336 retry = 1, dx = 0; // and schedule the diagonal moves for later
337 else dx = dy, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
338 break; // should not have direction indicators
339 default: return; // syntax error: invalid atom
341 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
342 mode = 0; // build mode mask
343 if(*desc == 'm') mode |= 4, desc++; // move to empty
344 if(*desc == 'c') mode |= his, desc++; // capture foe
345 if(*desc == 'd') mode |= mine, desc++; // destroy (capture friend)
346 if(*desc == 'e') mode |= 8, desc++; // e.p. capture last mover
347 if(*desc == 't') mode |= 16, desc++; // exclude enemies as hop platform ('test')
348 if(*desc == 'p') mode |= 32, desc++; // hop over occupied
349 if(*desc == 'g') mode |= 64, desc++; // hop and toggle range
350 if(*desc == 'o') mode |= 128, desc++; // wrap around cylinder board
351 if(*desc == 'y') mode |= 512, desc++; // toggle range on empty square
352 if(*desc == 'n') jump = 0, desc++; // non-jumping
353 while(*desc == 'j') jump++, desc++; // must jump (on B,R,Q: skip first square)
354 if(*desc == 'a') cont = ++desc; // move again after doing what preceded it
355 if(isdigit(*++p)) expo = atoi(p++); // read exponent
356 if(expo > 9) p++; // allow double-digit
357 desc = p; // this is start of next move
358 if(initial && (board[r][f] != initialPosition[r][f] ||
359 r == 0 && board[TOUCHED_W] & 1<<f ||
360 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
361 if(expo > 1 && dx == 0 && dy == 0) { // castling indicated by O + number
362 mode |= 1024; dy = 1;
365 if(!(mode & 15)) mode |= his + 4; // no mode spec, use default = mc
367 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
368 atom = buf; while(islower(*atom)) atom++; // skip to atom
369 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
370 if(mode & 64 + 512) {
371 mode |= 256; // and 'g' too, but converts leaper <-> slider
372 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
373 *atom = upgrade[*atom-'A']; // replace atom, BRQ <-> FWK
374 atom[1] = atom[2] = '\0'; // make sure any old range is stripped off
375 if(expo == 1) atom[1] = '0'; // turn other leapers into riders
377 if(!(mode & 0x30F)) mode |= 4; // and default of this leg = m
379 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
381 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
382 int i = expo, j = skip, hop = mode, vx, vy;
383 if(!(bit & dirSet)) continue; // does not move in this direction
384 if(dy != 1) j = 0; //
385 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
386 vy = dx*rot[dir][2] + dy*rot[dir][3];
387 if(tx < 0) x = f, y = r; // start square
388 else x = tx, y = ty; // from previous to-square if continuation
390 x += vx; y += vy; // step to next square
391 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
392 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT; else break; }
393 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT; else break; }
394 if(j) { j--; continue; } // skip irrespective of occupation
395 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
396 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
397 if(x == f && y == r) occup = 4; else // start square counts as empty
398 if(board[y][x] < BlackPawn) occup = 0x101; else
399 if(board[y][x] < EmptySquare) occup = 0x102; else
401 if(cont) { // non-final leg
402 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
403 if(occup & mode) { // valid intermediate square, do continuation
404 char origAtom = *atom;
405 if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
406 if(occup & mode & 0x104) // no side effects, merge legs to one move
407 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
408 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
410 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
411 if(cnt) { // and if there are
412 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
414 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
418 *atom = origAtom; // undo any interconversion
420 if(occup != 4) break; // occupied squares always terminate the leg
423 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
424 if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
425 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
427 if(mode & 1024) { // castling
428 i = 2; // kludge to elongate move indefinitely
429 if(occup == 4) continue; // skip empty squares
430 if(x == BOARD_LEFT && board[y][x] == initialPosition[y][x]) // reached initial corner piece
431 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
432 if(x == BOARD_RGHT-1 && board[y][x] == initialPosition[y][x])
433 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
436 if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
437 if(occup & mode) cb(board, flags, NormalMove, r, f, y, x, cl); // allowed, generate
438 if(occup != 4) break; // not valid transit square
441 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
442 } while(retry-- && ds2); // and start doing them
443 if(tx >= 0) break; // don't do other atoms in continuation legs
447 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
450 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
455 if (rt >= BOARD_HEIGHT) break;
456 if (SameColor(board[rf][ff], board[rt][ft])) break;
457 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
458 if (board[rt][ft] != EmptySquare) break;
463 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
469 if (SameColor(board[rf][ff], board[rt][ft])) break;
470 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
471 if (board[rt][ft] != EmptySquare) break;
476 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
478 SlideForward(board, flags, rf, ff, callback, closure);
479 SlideBackward(board, flags, rf, ff, callback, closure);
483 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
485 int i, s, rt = rf, ft;
486 for(s = -1; s <= 1; s+= 2) {
489 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
490 if (SameColor(board[rf][ff], board[rt][ft])) break;
491 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
492 if (board[rt][ft] != EmptySquare) break;
498 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
501 for(s = -1; s <= 1; s+= 2) {
505 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
506 if (SameColor(board[rf][ff], board[rt][ft])) break;
507 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
508 if (board[rt][ft] != EmptySquare) break;
514 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
517 for(s = -1; s <= 1; s+= 2) {
521 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
522 if (SameColor(board[rf][ff], board[rt][ft])) break;
523 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
524 if (board[rt][ft] != EmptySquare) break;
530 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
532 SlideVertical(board, flags, rf, ff, callback, closure);
533 SlideSideways(board, flags, rf, ff, callback, closure);
537 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
539 SlideDiagForward(board, flags, rf, ff, callback, closure);
540 SlideDiagBackward(board, flags, rf, ff, callback, closure);
544 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
545 { // Lion-like move of Horned Falcon and Souring Eagle
546 int ft = ff + dx, rt = rf + dy;
547 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
549 if (!SameColor(board[rf][ff], board[rt][ft]))
550 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
553 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
555 if (!SameColor(board[rf][ff], board[rt][ft]))
556 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
557 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
558 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
563 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
565 int ft = ff, rt = rf + 1;
566 if (rt >= BOARD_HEIGHT) return;
567 if (SameColor(board[rf][ff], board[rt][ft])) return;
568 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
572 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
574 int ft = ff, rt = rf - 1;
576 if (SameColor(board[rf][ff], board[rt][ft])) return;
577 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
581 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
585 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
586 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
588 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
589 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
593 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
596 if (rt >= BOARD_HEIGHT) return;
598 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
599 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
601 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
602 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
606 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
611 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
612 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
614 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
615 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
619 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
621 StepForward(board, flags, rf, ff, callback, closure);
622 StepBackward(board, flags, rf, ff, callback, closure);
626 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
628 StepDiagForward(board, flags, rf, ff, callback, closure);
629 StepDiagBackward(board, flags, rf, ff, callback, closure);
633 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
635 StepVertical(board, flags, rf, ff, callback, closure);
636 StepSideways(board, flags, rf, ff, callback, closure);
640 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
643 for (i = -1; i <= 1; i += 2)
644 for (j = -1; j <= 1; j += 2)
645 for (s = 1; s <= 2; s++) {
648 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
649 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
650 && !SameColor(board[rf][ff], board[rt][ft]))
651 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
655 /* Call callback once for each pseudo-legal move in the given
656 position, except castling moves. A move is pseudo-legal if it is
657 legal, or if it would be legal except that it leaves the king in
658 check. In the arguments, epfile is EP_NONE if the previous move
659 was not a double pawn push, or the file 0..7 if it was, or
660 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
661 Promotion moves generated are to Queen only.
664 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
665 // speed: only do moves with this piece type
668 int i, j, d, s, fs, rs, rt, ft, m;
669 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
670 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
672 for (rf = 0; rf < BOARD_HEIGHT; rf++)
673 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
676 if(board[rf][ff] == EmptySquare) continue;
677 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
678 m = 0; piece = board[rf][ff];
679 if(PieceToChar(piece) == '~')
680 piece = (ChessSquare) ( DEMOTED piece );
681 if(filter != EmptySquare && piece != filter) continue;
682 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
683 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
686 if(IS_SHOGI(gameInfo.variant))
687 piece = (ChessSquare) ( SHOGI piece );
689 switch ((int)piece) {
690 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
692 /* can't happen ([HGM] except for faries...) */
696 if(gameInfo.variant == VariantXiangqi) {
697 /* [HGM] capture and move straight ahead in Xiangqi */
698 if (rf < BOARD_HEIGHT-1 &&
699 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
700 callback(board, flags, NormalMove,
701 rf, ff, rf + 1, ff, closure);
703 /* and move sideways when across the river */
704 for (s = -1; s <= 1; s += 2) {
705 if (rf >= BOARD_HEIGHT>>1 &&
706 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
707 !WhitePiece(board[rf][ff+s]) ) {
708 callback(board, flags, NormalMove,
709 rf, ff, rf, ff+s, closure);
714 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
715 callback(board, flags,
716 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
717 rf, ff, rf + 1, ff, closure);
719 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
720 gameInfo.variant != VariantShatranj && /* [HGM] */
721 gameInfo.variant != VariantCourier && /* [HGM] */
722 board[rf+2][ff] == EmptySquare ) {
723 callback(board, flags, NormalMove,
724 rf, ff, rf+2, ff, closure);
726 for (s = -1; s <= 1; s += 2) {
727 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
728 ((flags & F_KRIEGSPIEL_CAPTURE) ||
729 BlackPiece(board[rf + 1][ff + s]))) {
730 callback(board, flags,
731 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
732 rf, ff, rf + 1, ff + s, closure);
734 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
735 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
736 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
737 board[rf][ff + s] == BlackPawn &&
738 board[rf+1][ff + s] == EmptySquare) {
739 callback(board, flags, WhiteCapturesEnPassant,
740 rf, ff, rf+1, ff + s, closure);
747 if(gameInfo.variant == VariantXiangqi) {
748 /* [HGM] capture straight ahead in Xiangqi */
749 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
750 callback(board, flags, NormalMove,
751 rf, ff, rf - 1, ff, closure);
753 /* and move sideways when across the river */
754 for (s = -1; s <= 1; s += 2) {
755 if (rf < BOARD_HEIGHT>>1 &&
756 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
757 !BlackPiece(board[rf][ff+s]) ) {
758 callback(board, flags, NormalMove,
759 rf, ff, rf, ff+s, closure);
764 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
765 callback(board, flags,
766 rf <= promoRank ? BlackPromotion : NormalMove,
767 rf, ff, rf - 1, ff, closure);
769 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
770 gameInfo.variant != VariantShatranj && /* [HGM] */
771 gameInfo.variant != VariantCourier && /* [HGM] */
772 board[rf-2][ff] == EmptySquare) {
773 callback(board, flags, NormalMove,
774 rf, ff, rf-2, ff, closure);
776 for (s = -1; s <= 1; s += 2) {
777 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
778 ((flags & F_KRIEGSPIEL_CAPTURE) ||
779 WhitePiece(board[rf - 1][ff + s]))) {
780 callback(board, flags,
781 rf <= promoRank ? BlackPromotion : NormalMove,
782 rf, ff, rf - 1, ff + s, closure);
784 if (rf < BOARD_HEIGHT>>1) {
785 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
786 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
787 board[rf][ff + s] == WhitePawn &&
788 board[rf-1][ff + s] == EmptySquare) {
789 callback(board, flags, BlackCapturesEnPassant,
790 rf, ff, rf-1, ff + s, closure);
800 for (i = -1; i <= 1; i += 2)
801 for (j = -1; j <= 1; j += 2)
802 for (s = 1; s <= 2; s++) {
805 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
806 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
807 && !SameColor(board[rf][ff], board[rt][ft]))
808 callback(board, flags, NormalMove,
809 rf, ff, rt, ft, closure);
813 case SHOGI WhiteKnight:
814 for (s = -1; s <= 1; s += 2) {
815 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
816 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
817 callback(board, flags, NormalMove,
818 rf, ff, rf + 2, ff + s, closure);
823 case SHOGI BlackKnight:
824 for (s = -1; s <= 1; s += 2) {
825 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
826 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
827 callback(board, flags, NormalMove,
828 rf, ff, rf - 2, ff + s, closure);
835 for (d = 0; d <= 1; d++)
836 for (s = -1; s <= 1; s += 2) {
839 rt = rf + (i * s) * d;
840 ft = ff + (i * s) * (1 - d);
841 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
842 if (m == 0 && board[rt][ft] == EmptySquare)
843 callback(board, flags, NormalMove,
844 rf, ff, rt, ft, closure);
845 if (m == 1 && board[rt][ft] != EmptySquare &&
846 !SameColor(board[rf][ff], board[rt][ft]) )
847 callback(board, flags, NormalMove,
848 rf, ff, rt, ft, closure);
849 if (board[rt][ft] != EmptySquare && m++) break;
854 /* Gold General (and all its promoted versions) . First do the */
855 /* diagonal forward steps, then proceed as normal Wazir */
856 case SHOGI (PROMOTED WhitePawn):
857 if(gameInfo.variant == VariantShogi) goto WhiteGold;
858 case SHOGI (PROMOTED BlackPawn):
859 if(gameInfo.variant == VariantShogi) goto BlackGold;
860 SlideVertical(board, flags, rf, ff, callback, closure);
863 case SHOGI (PROMOTED WhiteKnight):
864 if(gameInfo.variant == VariantShogi) goto WhiteGold;
865 case SHOGI BlackDrunk:
866 case SHOGI BlackAlfil:
867 Ferz(board, flags, rf, ff, callback, closure);
868 StepSideways(board, flags, rf, ff, callback, closure);
869 StepBackward(board, flags, rf, ff, callback, closure);
872 case SHOGI (PROMOTED BlackKnight):
873 if(gameInfo.variant == VariantShogi) goto BlackGold;
874 case SHOGI WhiteDrunk:
875 case SHOGI WhiteAlfil:
876 Ferz(board, flags, rf, ff, callback, closure);
877 StepSideways(board, flags, rf, ff, callback, closure);
878 StepForward(board, flags, rf, ff, callback, closure);
882 case SHOGI WhiteStag:
883 case SHOGI BlackStag:
884 if(gameInfo.variant == VariantShogi) goto BlackGold;
885 SlideVertical(board, flags, rf, ff, callback, closure);
886 Ferz(board, flags, rf, ff, callback, closure);
887 StepSideways(board, flags, rf, ff, callback, closure);
890 case SHOGI (PROMOTED WhiteQueen):
891 case SHOGI WhiteTokin:
892 case SHOGI WhiteWazir:
894 StepDiagForward(board, flags, rf, ff, callback, closure);
895 Wazir(board, flags, rf, ff, callback, closure);
898 case SHOGI (PROMOTED BlackQueen):
899 case SHOGI BlackTokin:
900 case SHOGI BlackWazir:
902 StepDiagBackward(board, flags, rf, ff, callback, closure);
903 Wazir(board, flags, rf, ff, callback, closure);
908 Wazir(board, flags, rf, ff, callback, closure);
911 case SHOGI WhiteMarshall:
912 case SHOGI BlackMarshall:
913 Ferz(board, flags, rf, ff, callback, closure);
914 for (d = 0; d <= 1; d++)
915 for (s = -2; s <= 2; s += 4) {
917 ft = ff + s * (1 - d);
918 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
919 if (!SameColor(board[rf][ff], board[rt][ft]) )
920 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
924 case SHOGI WhiteAngel:
925 case SHOGI BlackAngel:
926 Wazir(board, flags, rf, ff, callback, closure);
930 /* [HGM] support Shatranj pieces */
931 for (rs = -1; rs <= 1; rs += 2)
932 for (fs = -1; fs <= 1; fs += 2) {
935 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
936 && ( gameInfo.variant != VariantXiangqi ||
937 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
939 && !SameColor(board[rf][ff], board[rt][ft]))
940 callback(board, flags, NormalMove,
941 rf, ff, rt, ft, closure);
942 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
943 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
944 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
946 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
947 && !SameColor(board[rf][ff], board[rt][ft]))
948 callback(board, flags, NormalMove,
949 rf, ff, rt, ft, closure);
951 if(gameInfo.variant == VariantSpartan)
952 for(fs = -1; fs <= 1; fs += 2) {
954 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
955 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
959 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
962 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
963 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
964 for (s = -2; s <= 2; s += 4) {
966 ft = ff + s * (1 - d);
967 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
968 if (SameColor(board[rf][ff], board[rt][ft])) continue;
969 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
972 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
973 case SHOGI WhiteCardinal:
974 case SHOGI BlackCardinal:
975 case SHOGI WhitePCardinal:
976 case SHOGI BlackPCardinal:
978 Bishop(board, flags, rf, ff, callback, closure);
979 Wazir(board, flags, rf, ff, callback, closure);
982 /* Capablanca Archbishop continues as Knight */
985 Knight(board, flags, rf, ff, callback, closure);
987 /* Shogi Bishops are ordinary Bishops */
988 case SHOGI WhiteBishop:
989 case SHOGI BlackBishop:
990 case SHOGI WhitePBishop:
991 case SHOGI BlackPBishop:
994 Bishop(board, flags, rf, ff, callback, closure);
997 /* Shogi Lance is unlike anything, and asymmetric at that */
998 case SHOGI WhiteQueen:
999 if(gameInfo.variant == VariantChu) goto doQueen;
1003 if (rt >= BOARD_HEIGHT) break;
1004 if (SameColor(board[rf][ff], board[rt][ft])) break;
1005 callback(board, flags, NormalMove,
1006 rf, ff, rt, ft, closure);
1007 if (board[rt][ft] != EmptySquare) break;
1011 case SHOGI BlackQueen:
1012 if(gameInfo.variant == VariantChu) goto doQueen;
1017 if (SameColor(board[rf][ff], board[rt][ft])) break;
1018 callback(board, flags, NormalMove,
1019 rf, ff, rt, ft, closure);
1020 if (board[rt][ft] != EmptySquare) break;
1024 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1027 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1028 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1029 for (s = -2; s <= 2; s += 4) {
1031 ft = ff + s * (1 - d);
1032 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1033 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1034 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1035 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1037 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1038 Wazir(board, flags, rf, ff, callback, closure);
1040 Rook(board, flags, rf, ff, callback, closure);
1043 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1044 case SHOGI WhiteDragon:
1045 case SHOGI BlackDragon:
1046 case SHOGI WhitePDragon:
1047 case SHOGI BlackPDragon:
1049 Rook(board, flags, rf, ff, callback, closure);
1050 Ferz(board, flags, rf, ff, callback, closure);
1054 /* Capablanca Chancellor sets flag to continue as Knight */
1057 Rook(board, flags, rf, ff, callback, closure);
1058 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1059 Ferz(board, flags, rf, ff, callback, closure);
1061 Knight(board, flags, rf, ff, callback, closure);
1064 /* Shogi Rooks are ordinary Rooks */
1065 case SHOGI WhiteRook:
1066 case SHOGI BlackRook:
1067 case SHOGI WhitePRook:
1068 case SHOGI BlackPRook:
1071 Rook(board, flags, rf, ff, callback, closure);
1076 case SHOGI WhiteMother:
1077 case SHOGI BlackMother:
1079 Rook(board, flags, rf, ff, callback, closure);
1080 Bishop(board, flags, rf, ff, callback, closure);
1083 case SHOGI WhitePawn:
1084 StepForward(board, flags, rf, ff, callback, closure);
1087 case SHOGI BlackPawn:
1088 StepBackward(board, flags, rf, ff, callback, closure);
1092 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1093 case SHOGI WhiteFerz:
1094 Ferz(board, flags, rf, ff, callback, closure);
1095 StepForward(board, flags, rf, ff, callback, closure);
1099 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1100 case SHOGI BlackFerz:
1101 StepBackward(board, flags, rf, ff, callback, closure);
1105 /* [HGM] support Shatranj pieces */
1106 Ferz(board, flags, rf, ff, callback, closure);
1111 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1114 case SHOGI WhiteMonarch:
1115 case SHOGI BlackMonarch:
1116 case SHOGI WhiteKing:
1117 case SHOGI BlackKing:
1120 Ferz(board, flags, rf, ff, callback, closure);
1121 Wazir(board, flags, rf, ff, callback, closure);
1124 case WhiteNightrider:
1125 case BlackNightrider:
1126 for (i = -1; i <= 1; i += 2)
1127 for (j = -1; j <= 1; j += 2)
1128 for (s = 1; s <= 2; s++) { int k;
1131 ft = ff + k*j*(3-s);
1132 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1133 if (SameColor(board[rf][ff], board[rt][ft])) break;
1134 callback(board, flags, NormalMove,
1135 rf, ff, rt, ft, closure);
1136 if (board[rt][ft] != EmptySquare) break;
1142 Bishop(board, flags, rf, ff, callback, closure);
1143 Rook(board, flags, rf, ff, callback, closure);
1144 Knight(board, flags, rf, ff, callback, closure);
1147 // Use Lance as Berolina / Spartan Pawn.
1149 if(gameInfo.variant == VariantSuper) goto Amazon;
1150 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1151 callback(board, flags,
1152 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1153 rf, ff, rf + 1, ff, closure);
1154 for (s = -1; s <= 1; s += 2) {
1155 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1156 callback(board, flags,
1157 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1158 rf, ff, rf + 1, ff + s, closure);
1159 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1160 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1165 if(gameInfo.variant == VariantSuper) goto Amazon;
1166 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1167 callback(board, flags,
1168 rf <= promoRank ? BlackPromotion : NormalMove,
1169 rf, ff, rf - 1, ff, closure);
1170 for (s = -1; s <= 1; s += 2) {
1171 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1172 callback(board, flags,
1173 rf <= promoRank ? BlackPromotion : NormalMove,
1174 rf, ff, rf - 1, ff + s, closure);
1175 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1176 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1180 case SHOGI WhiteNothing:
1181 case SHOGI BlackNothing:
1182 case SHOGI WhiteLion:
1183 case SHOGI BlackLion:
1186 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1187 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1188 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1189 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1190 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1191 rf, ff, rt, ft, closure);
1196 case SHOGI WhiteFalcon:
1197 case SHOGI BlackFalcon:
1198 case SHOGI WhitePDagger:
1199 case SHOGI BlackPDagger:
1200 SlideSideways(board, flags, rf, ff, callback, closure);
1201 StepVertical(board, flags, rf, ff, callback, closure);
1204 case SHOGI WhiteCobra:
1205 case SHOGI BlackCobra:
1206 StepVertical(board, flags, rf, ff, callback, closure);
1209 case SHOGI (PROMOTED WhiteFerz):
1210 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1211 case SHOGI (PROMOTED BlackFerz):
1212 if(gameInfo.variant == VariantShogi) goto BlackGold;
1213 case SHOGI WhitePSword:
1214 case SHOGI BlackPSword:
1215 SlideVertical(board, flags, rf, ff, callback, closure);
1216 StepSideways(board, flags, rf, ff, callback, closure);
1219 case SHOGI WhiteUnicorn:
1220 case SHOGI BlackUnicorn:
1221 Ferz(board, flags, rf, ff, callback, closure);
1222 StepVertical(board, flags, rf, ff, callback, closure);
1225 case SHOGI WhiteMan:
1226 StepDiagForward(board, flags, rf, ff, callback, closure);
1227 StepVertical(board, flags, rf, ff, callback, closure);
1230 case SHOGI BlackMan:
1231 StepDiagBackward(board, flags, rf, ff, callback, closure);
1232 StepVertical(board, flags, rf, ff, callback, closure);
1235 case SHOGI WhiteHCrown:
1236 case SHOGI BlackHCrown:
1237 Bishop(board, flags, rf, ff, callback, closure);
1238 SlideSideways(board, flags, rf, ff, callback, closure);
1241 case SHOGI WhiteCrown:
1242 case SHOGI BlackCrown:
1243 Bishop(board, flags, rf, ff, callback, closure);
1244 SlideVertical(board, flags, rf, ff, callback, closure);
1247 case SHOGI WhiteHorned:
1248 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1249 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1250 if(killX >= 0) break;
1251 Bishop(board, flags, rf, ff, callback, closure);
1252 SlideSideways(board, flags, rf, ff, callback, closure);
1253 SlideBackward(board, flags, rf, ff, callback, closure);
1256 case SHOGI BlackHorned:
1257 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1258 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1259 if(killX >= 0) break;
1260 Bishop(board, flags, rf, ff, callback, closure);
1261 SlideSideways(board, flags, rf, ff, callback, closure);
1262 SlideForward(board, flags, rf, ff, callback, closure);
1265 case SHOGI WhiteEagle:
1266 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1267 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1268 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1269 if(killX >= 0) break;
1270 Rook(board, flags, rf, ff, callback, closure);
1271 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1274 case SHOGI BlackEagle:
1275 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1276 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1277 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1278 if(killX >= 0) break;
1279 Rook(board, flags, rf, ff, callback, closure);
1280 SlideDiagForward(board, flags, rf, ff, callback, closure);
1283 case SHOGI WhiteDolphin:
1284 case SHOGI BlackHorse:
1285 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1286 SlideVertical(board, flags, rf, ff, callback, closure);
1289 case SHOGI BlackDolphin:
1290 case SHOGI WhiteHorse:
1291 SlideDiagForward(board, flags, rf, ff, callback, closure);
1292 SlideVertical(board, flags, rf, ff, callback, closure);
1295 case SHOGI WhiteLance:
1296 SlideForward(board, flags, rf, ff, callback, closure);
1299 case SHOGI BlackLance:
1300 SlideBackward(board, flags, rf, ff, callback, closure);
1303 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1307 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1320 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1321 Board xqCheckers, nullBoard;
1323 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1324 int rf, int ff, int rt, int ft,
1328 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1330 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1332 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1334 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1336 if (!(flags & F_IGNORE_CHECK) ) {
1337 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1340 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1341 kings += (board[r][f] == BlackKing);
1345 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1347 check = CheckTest(board, flags, rf, ff, rt, ft,
1348 kind == WhiteCapturesEnPassant ||
1349 kind == BlackCapturesEnPassant);
1350 if(promo) board[rf][ff] = BlackLance;
1353 if (flags & F_ATOMIC_CAPTURE) {
1354 if (board[rt][ft] != EmptySquare ||
1355 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1357 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1358 if (board[rf][ff] == king) return;
1359 for (r = rt-1; r <= rt+1; r++) {
1360 for (f = ft-1; f <= ft+1; f++) {
1361 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1362 board[r][f] == king) return;
1367 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1374 int captures; // [HGM] losers
1375 } LegalityTestClosure;
1378 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1379 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1380 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1381 moves that would destroy your own king. The CASTLE_OK flags are
1382 true if castling is not yet ruled out by a move of the king or
1383 rook. Return TRUE if the player on move is currently in check and
1384 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1386 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1389 int ff, ft, k, left, right, swap;
1390 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1391 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1392 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1397 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1398 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1399 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1401 if (inCheck) return TRUE;
1403 /* Generate castling moves */
1404 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1405 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1408 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1409 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1411 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1412 if ((flags & F_WHITE_ON_MOVE) &&
1413 (flags & F_WHITE_KCASTLE_OK) &&
1414 board[0][ff] == wKing &&
1415 board[0][ff + 1] == EmptySquare &&
1416 board[0][ff + 2] == EmptySquare &&
1417 board[0][BOARD_RGHT-3] == EmptySquare &&
1418 board[0][BOARD_RGHT-2] == EmptySquare &&
1419 board[0][BOARD_RGHT-1] == WhiteRook &&
1420 castlingRights[0] != NoRights && /* [HGM] check rights */
1421 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1423 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1424 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1425 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1426 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1428 callback(board, flags,
1429 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1430 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1432 if ((flags & F_WHITE_ON_MOVE) &&
1433 (flags & F_WHITE_QCASTLE_OK) &&
1434 board[0][ff] == wKing &&
1435 board[0][ff - 1] == EmptySquare &&
1436 board[0][ff - 2] == EmptySquare &&
1437 board[0][BOARD_LEFT+2] == EmptySquare &&
1438 board[0][BOARD_LEFT+1] == EmptySquare &&
1439 board[0][BOARD_LEFT+0] == WhiteRook &&
1440 castlingRights[1] != NoRights && /* [HGM] check rights */
1441 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1443 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1444 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1445 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1447 callback(board, flags,
1448 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1449 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1451 if (!(flags & F_WHITE_ON_MOVE) &&
1452 (flags & F_BLACK_KCASTLE_OK) &&
1453 board[BOARD_HEIGHT-1][ff] == bKing &&
1454 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1455 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1456 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1457 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1458 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1459 castlingRights[3] != NoRights && /* [HGM] check rights */
1460 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1462 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1463 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1464 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1465 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1467 callback(board, flags,
1468 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1469 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1471 if (!(flags & F_WHITE_ON_MOVE) &&
1472 (flags & F_BLACK_QCASTLE_OK) &&
1473 board[BOARD_HEIGHT-1][ff] == bKing &&
1474 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1475 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1476 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1477 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1478 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1479 castlingRights[4] != NoRights && /* [HGM] check rights */
1480 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1482 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1483 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1484 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1486 callback(board, flags,
1487 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1488 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1492 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1494 /* generate all potential FRC castling moves (KxR), ignoring flags */
1495 /* [HGM] test if the Rooks we find have castling rights */
1496 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1499 if ((flags & F_WHITE_ON_MOVE) != 0) {
1500 ff = castlingRights[2]; /* King file if we have any rights */
1501 if(ff != NoRights && board[0][ff] == WhiteKing) {
1502 if (appData.debugMode) {
1503 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1504 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1506 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1508 right = BOARD_RGHT-2;
1509 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1510 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1511 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1512 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1513 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1514 if(ft != NoRights && board[0][ft] == WhiteRook) {
1515 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1516 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1519 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1520 left = BOARD_LEFT+2;
1522 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1523 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1524 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1525 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1526 if(ff > BOARD_LEFT+2)
1527 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1528 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1529 if(ft != NoRights && board[0][ft] == WhiteRook) {
1530 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1531 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1535 ff = castlingRights[5]; /* King file if we have any rights */
1536 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1537 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1539 right = BOARD_RGHT-2;
1540 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1541 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1542 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1543 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1544 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1545 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1546 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1547 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1550 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1551 left = BOARD_LEFT+2;
1553 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1554 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1555 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1556 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1557 if(ff > BOARD_LEFT+2)
1558 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1559 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1560 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1561 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1562 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1579 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1580 int rf, int ff, int rt, int ft,
1585 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1587 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1589 if (rt == cl->rking && ft == cl->fking) {
1590 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1592 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1594 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1595 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1596 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1600 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1601 he leave himself in check? Or if rf == -1, is the player on move
1602 in check now? enPassant must be TRUE if the indicated move is an
1603 e.p. capture. The possibility of castling out of a check along the
1604 back rank is not accounted for (i.e., we still return nonzero), as
1605 this is illegal anyway. Return value is the number of times the
1606 king is in check. */
1608 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1610 CheckTestClosure cl;
1611 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1612 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1613 /* Suppress warnings on uninitialized variables */
1615 if(gameInfo.variant == VariantXiangqi)
1616 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1617 if(gameInfo.variant == VariantKnightmate)
1618 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1619 if(gameInfo.variant == VariantChu) { // strictly speaking this is not needed, as Chu officially has no check
1620 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1621 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1622 if(board[r][f] == k || board[r][f] == prince) {
1623 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1624 king = board[r][f]; // remember hich one we had
1631 captured = board[rf][ft];
1632 board[rf][ft] = EmptySquare;
1634 captured = board[rt][ft];
1635 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; }
1637 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1638 board[rt][ft] = board[rf][ff];
1639 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1641 ep = board[EP_STATUS];
1642 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1643 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1644 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1645 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1646 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1647 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1651 /* For compatibility with ICS wild 9, we scan the board in the
1652 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1653 and we test only whether that one is in check. */
1654 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1655 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1656 if (board[cl.rking][cl.fking] == king) {
1658 if(gameInfo.variant == VariantXiangqi) {
1659 /* [HGM] In Xiangqi opposing Kings means check as well */
1661 dir = (king >= BlackPawn) ? -1 : 1;
1662 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1663 board[i][cl.fking] == EmptySquare; i+=dir );
1664 if(i>=0 && i<BOARD_HEIGHT &&
1665 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1668 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1669 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1670 goto undo_move; /* 2-level break */
1677 if(rf != DROP_RANK) // [HGM] drop
1678 board[rf][ff] = board[rt][ft];
1680 board[rf][ft] = captured;
1681 board[rt][ft] = EmptySquare;
1683 if(killX >= 0) board[killY][killX] = trampled;
1684 board[rt][ft] = captured;
1686 board[EP_STATUS] = ep;
1689 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1693 HasLion (Board board, int flags)
1695 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1697 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1698 if(board[r][f] == lion) return 1;
1703 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1704 { // [HGM] put drop legality testing in separate routine for clarity
1706 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1707 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1708 n = PieceToNumber(piece);
1709 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1710 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1711 return ImpossibleMove; // piece not available
1712 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1713 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1714 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1715 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1716 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1717 if(piece == WhitePawn || piece == BlackPawn) {
1718 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1719 for(r=1; r<BOARD_HEIGHT-1; r++)
1720 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1721 // should still test if we mate with this Pawn
1723 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1724 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1726 if( (piece == WhitePawn || piece == BlackPawn) &&
1727 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1728 return IllegalMove; /* no pawn drops on 1st/8th */
1730 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1731 if (!(flags & F_IGNORE_CHECK) &&
1732 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1733 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1736 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1737 int rf, int ff, int rt, int ft,
1741 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1743 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1745 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1746 cl->captures++; // [HGM] losers: count legal captures
1747 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1752 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1754 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1756 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1757 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1758 piece = filterPiece = board[rf][ff];
1759 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1761 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1762 /* (perhaps we should disallow moves that obviously leave us in check?) */
1763 if((piece == WhiteFalcon || piece == BlackFalcon ||
1764 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1765 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1769 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1770 cl.ft = fFilter = ft;
1771 cl.kind = IllegalMove;
1772 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1773 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1774 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1775 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1776 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1777 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1779 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1780 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1781 if(board[rf][ff] < BlackPawn) { // white
1782 if(rf != 0) return IllegalMove; // must be on back rank
1783 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1784 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1785 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1786 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1788 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1789 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1790 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1791 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1792 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1795 if(gameInfo.variant == VariantChu) {
1796 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1797 if(promoChar != '+')
1798 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1799 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1800 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1802 if(gameInfo.variant == VariantShogi) {
1803 /* [HGM] Shogi promotions. '=' means defer */
1804 if(rf != DROP_RANK && cl.kind == NormalMove) {
1805 ChessSquare piece = board[rf][ff];
1807 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1808 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1809 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1810 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1811 promoChar = '+'; // allowed ICS notations
1812 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1813 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1814 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1815 else if(flags & F_WHITE_ON_MOVE) {
1816 if( (int) piece < (int) WhiteWazir &&
1817 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1818 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1819 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1820 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1821 else /* promotion optional, default is defer */
1822 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1823 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1825 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1826 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1827 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1828 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1829 else /* promotion optional, default is defer */
1830 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1831 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1835 if (promoChar != NULLCHAR) {
1836 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1837 ChessSquare piece = board[rf][ff];
1838 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1839 // should test if in zone, really
1840 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1842 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1844 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1845 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1846 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1847 if(piece == EmptySquare)
1848 cl.kind = ImpossibleMove; // non-existing piece
1849 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1850 cl.kind = IllegalMove; // no two Lions
1851 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1852 if(promoChar != PieceToChar(BlackKing)) {
1853 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1854 if(piece == BlackLance) cl.kind = ImpossibleMove;
1855 } else { // promotion to King allowed only if we do not have two yet
1856 int r, f, kings = 0;
1857 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1858 if(kings == 2) cl.kind = IllegalMove;
1860 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1861 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1862 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1863 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1864 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1865 cl.kind = IllegalMove; // promotion to King usually not allowed
1867 cl.kind = IllegalMove;
1877 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1878 int rf, int ff, int rt, int ft,
1882 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1884 register MateTestClosure *cl = (MateTestClosure *) closure;
1889 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1891 MateTest (Board board, int flags)
1894 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1895 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1897 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1898 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1899 nrKing += (board[r][f] == king); // stm has king
1900 if( board[r][f] != EmptySquare ) {
1901 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1906 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1907 case VariantShatranj:
1908 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1912 if(nrKing == 0) return MT_NOKING;
1915 if(myPieces == 1) return MT_BARE;
1918 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1919 // [HGM] 3check: yet to do!
1921 return inCheck ? MT_CHECK : MT_NONE;
1923 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1924 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1925 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1926 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1927 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1928 if(board[n][holdings] != EmptySquare) {
1929 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1930 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1933 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1934 return myPieces == hisPieces ? MT_STALEMATE :
1935 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1936 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1937 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1939 return inCheck ? MT_CHECKMATE
1940 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1941 MT_STAINMATE : MT_STALEMATE;
1946 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1947 int rf, int ff, int rt, int ft,
1951 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1953 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1954 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1956 // [HGM] wild: for wild-card pieces rt and rf are dummies
1957 if(piece == WhiteFalcon || piece == BlackFalcon ||
1958 piece == WhiteCobra || piece == BlackCobra)
1961 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1962 || PieceToChar(board[rf][ff]) == '~'
1963 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1965 (cl->rfIn == -1 || cl->rfIn == rf) &&
1966 (cl->ffIn == -1 || cl->ffIn == ff) &&
1967 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1968 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1970 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1973 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1974 // [HGM] oneclick: if multiple moves, be sure we remember capture
1975 cl->piece = board[rf][ff];
1978 cl->rt = wildCard ? cl->rtIn : rt;
1979 cl->ft = wildCard ? cl->ftIn : ft;
1982 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1987 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1989 int illegal = 0; char c = closure->promoCharIn;
1991 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1992 closure->count = closure->captures = 0;
1993 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1994 closure->kind = ImpossibleMove;
1995 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1996 fFilter = closure->ftIn;
1997 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1998 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1999 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
2000 closure->count = closure->captures = 0;
2001 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2002 closure->kind = ImpossibleMove;
2003 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2006 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2007 if (closure->count == 0) {
2008 /* See if it's an illegal move due to check */
2010 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2011 if (closure->count == 0) {
2012 /* No, it's not even that */
2013 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2014 int f, r; // if there is only a single piece of the requested type on the board, use that
2015 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2016 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2017 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2018 if(closure->count > 1) illegal = 0; // ambiguous
2020 if(closure->count == 0) {
2021 if (appData.debugMode) { int i, j;
2022 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2023 for(j=0; j<BOARD_WIDTH; j++)
2024 fprintf(debugFP, "%3d", (int) board[i][j]);
2025 fprintf(debugFP, "\n");
2031 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2032 DisambiguateClosure spare = *closure;
2033 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2034 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2035 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2039 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2040 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2041 if(closure->piece < BlackPawn) { // white
2042 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2043 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2044 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2045 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2046 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2048 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2049 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2050 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2051 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2052 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2055 if(gameInfo.variant == VariantChu) {
2056 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2058 if(gameInfo.variant == VariantShogi) {
2059 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2060 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2061 ChessSquare piece = closure->piece;
2062 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2063 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2064 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2065 c = '+'; // allowed ICS notations
2066 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2067 else if(flags & F_WHITE_ON_MOVE) {
2068 if( (int) piece < (int) WhiteWazir &&
2069 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2070 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2071 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2072 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2073 else /* promotion optional, default is defer */
2074 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2075 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2077 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2078 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2079 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2080 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2081 else /* promotion optional, default is defer */
2082 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2083 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2086 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2087 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2089 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2090 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2091 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2092 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2093 c = PieceToChar(BlackFerz);
2094 else if(gameInfo.variant == VariantGreat)
2095 c = PieceToChar(BlackMan);
2096 else if(gameInfo.variant == VariantGrand)
2097 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2099 c = PieceToChar(BlackQueen);
2100 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2101 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2102 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2103 ChessSquare p = closure->piece;
2104 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2105 closure->kind = ImpossibleMove; // used on non-promotable piece
2106 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2107 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2109 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2110 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2111 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2112 if (closure->count > 1) {
2113 closure->kind = AmbiguousMove;
2116 /* Note: If more than one illegal move matches, but no legal
2117 moves, we return IllegalMove, not AmbiguousMove. Caller
2118 can look at closure->count to detect this.
2120 closure->kind = IllegalMove;
2134 } CoordsToAlgebraicClosure;
2136 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2137 ChessMove kind, int rf, int ff,
2138 int rt, int ft, VOIDSTAR closure));
2141 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2143 register CoordsToAlgebraicClosure *cl =
2144 (CoordsToAlgebraicClosure *) closure;
2146 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2147 (board[rf][ff] == cl->piece
2148 || PieceToChar(board[rf][ff]) == '~' &&
2149 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2153 cl->kind = kind; /* this is the move we want */
2155 cl->file++; /* need file to rule out this move */
2159 cl->rank++; /* need rank to rule out this move */
2161 cl->either++; /* rank or file will rule out this move */
2167 /* Convert coordinates to normal algebraic notation.
2168 promoChar must be NULLCHAR or 'x' if not a promotion.
2171 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2175 char *outp = out, c, capture;
2176 CoordsToAlgebraicClosure cl;
2178 if (rf == DROP_RANK) {
2179 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2180 /* Bughouse piece drop */
2181 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2186 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2188 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2191 if (promoChar == 'x') promoChar = NULLCHAR;
2192 piece = board[rf][ff];
2193 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2198 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2199 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2200 /* Keep short notation if move is illegal only because it
2201 leaves the player in check, but still return IllegalMove */
2202 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2203 if (kind == IllegalMove) break;
2208 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2209 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2210 /* Non-capture; use style "e5" */
2213 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2215 /* Capture; use style "exd5" */
2217 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2221 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2223 /* Use promotion suffix style "=Q" */
2225 if (promoChar != NULLCHAR) {
2226 if(IS_SHOGI(gameInfo.variant)) {
2227 /* [HGM] ... but not in Shogi! */
2228 *outp++ = promoChar == '=' ? '=' : '+';
2231 *outp++ = ToUpper(promoChar);
2240 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2241 /* Code added by Tord: FRC castling. */
2242 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2243 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2245 safeStrCpy(out, "O-O", MOVE_LEN);
2247 safeStrCpy(out, "O-O-O", MOVE_LEN);
2248 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2250 /* End of code added by Tord */
2251 /* Test for castling or ICS wild castling */
2252 /* Use style "O-O" (oh-oh) for PGN compatibility */
2253 else if (rf == rt &&
2254 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2255 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2256 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2257 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2258 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2259 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2261 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2263 /* This notation is always unambiguous, unless there are
2264 kings on both the d and e files, with "wild castling"
2265 possible for the king on the d file and normal castling
2266 possible for the other. ICS rules for wild 9
2267 effectively make castling illegal for either king in
2268 this situation. So I am not going to worry about it;
2269 I'll just generate an ambiguous O-O in this case.
2271 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2274 /* else fall through */
2279 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2280 cl.ft = fFilter = ft;
2282 cl.kind = IllegalMove;
2283 cl.rank = cl.file = cl.either = 0;
2284 c = PieceToChar(piece) ;
2285 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2287 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2288 /* Generate pretty moves for moving into check, but
2289 still return IllegalMove.
2291 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2292 if (cl.kind == IllegalMove) break;
2293 cl.kind = IllegalMove;
2296 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2297 else "Ngf3" or "Ngxf7",
2298 else "N1f3" or "N5xf7",
2299 else "Ng1f3" or "Ng5xf7".
2301 if( c == '~' || c == '+') {
2302 /* [HGM] print nonexistent piece as its demoted version */
2303 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2305 if(c=='+') *outp++ = c;
2306 *outp++ = ToUpper(PieceToChar(piece));
2308 if (cl.file || (cl.either && !cl.rank)) {
2314 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2317 if(board[rt][ft] != EmptySquare)
2323 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2324 if (IS_SHOGI(gameInfo.variant)) {
2325 /* [HGM] in Shogi non-pawns can promote */
2326 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2328 else if (gameInfo.variant == VariantChuChess && promoChar ||
2329 gameInfo.variant != VariantSuper && promoChar &&
2330 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2332 *outp++ = ToUpper(promoChar);
2334 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2336 *outp++ = ToUpper(promoChar);
2342 /* Moving a nonexistent piece */
2346 /* Not a legal move, even ignoring check.
2347 If there was a piece on the from square,
2348 use style "Ng1g3" or "Ng1xe8";
2349 if there was a pawn or nothing (!),
2350 use style "g1g3" or "g1xe8". Use "x"
2351 if a piece was on the to square, even
2352 a piece of the same color.
2356 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2358 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2359 c += (board[r][f] == piece); // count on-board pieces of given type
2360 *outp++ = ToUpper(PieceToChar(piece));
2362 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2366 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2368 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2372 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2373 /* Use promotion suffix style "=Q" */
2374 if (promoChar != NULLCHAR && promoChar != 'x') {
2376 *outp++ = ToUpper(promoChar);
2383 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2392 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2394 int preyStackPointer, chaseStackPointer;
2397 unsigned char rf, ff, rt, ft;
2401 unsigned char rank, file;
2407 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2409 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2410 int rf, int ff, int rt, int ft,
2414 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2415 { // For adding captures that can lead to chase indictment to the chaseStack
2416 if(board[rt][ft] == EmptySquare) return; // non-capture
2417 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2418 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2419 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2420 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2421 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2422 chaseStack[chaseStackPointer].rf = rf;
2423 chaseStack[chaseStackPointer].ff = ff;
2424 chaseStack[chaseStackPointer].rt = rt;
2425 chaseStack[chaseStackPointer].ft = ft;
2426 chaseStackPointer++;
2429 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2430 int rf, int ff, int rt, int ft,
2434 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2435 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2437 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2439 if(board[rt][ft] == EmptySquare) return; // no capture
2440 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2441 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2443 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2444 for(i=0; i<chaseStackPointer; i++) {
2445 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2446 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2447 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2448 chaseStack[i] = chaseStack[--chaseStackPointer];
2454 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2455 int rf, int ff, int rt, int ft,
2459 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2460 { // for determining if a piece (given through the closure) is protected
2461 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2463 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2464 if(appData.debugMode && board[rt][ft] != EmptySquare)
2465 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2468 extern char moveList[MAX_MOVES][MOVE_LEN];
2471 PerpetualChase (int first, int last)
2472 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2475 ChessSquare captured;
2477 preyStackPointer = 0; // clear stack of chased pieces
2478 for(i=first; i<last; i+=2) { // for all positions with same side to move
2479 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2480 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2481 // determine all captures possible after the move, and put them on chaseStack
2482 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2483 if(appData.debugMode) { int n;
2484 for(n=0; n<chaseStackPointer; n++)
2485 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2486 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2487 fprintf(debugFP, ": all capts\n");
2489 // determine all captures possible before the move, and delete them from chaseStack
2490 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2491 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2492 cl.rt = moveList[i][3]-ONE;
2493 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2494 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2495 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2496 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2497 if(appData.debugMode) { int n;
2498 for(n=0; n<chaseStackPointer; n++)
2499 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2500 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2501 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2503 // chaseSack now contains all captures made possible by the move
2504 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2505 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2506 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2508 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2509 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2511 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2512 continue; // C or H attack on R is always chase; leave on chaseStack
2514 if(attacker == victim) {
2515 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2516 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2517 // we can capture back with equal piece, so this is no chase but a sacrifice
2518 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2519 j--; /* ! */ continue;
2524 // the attack is on a lower piece, or on a pinned or blocked equal one
2525 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2526 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2527 // test if the victim is protected by a true protector. First make the capture.
2528 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2529 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2530 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2531 // Then test if the opponent can recapture
2532 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2533 cl.rt = chaseStack[j].rt;
2534 cl.ft = chaseStack[j].ft;
2535 if(appData.debugMode) {
2536 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2538 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2539 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2540 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2541 // unmake the capture
2542 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2543 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2544 // if a recapture was found, piece is protected, and we are not chasing it.
2545 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2546 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2550 // chaseStack now contains all moves that chased
2551 if(appData.debugMode) { int n;
2552 for(n=0; n<chaseStackPointer; n++)
2553 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2554 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2555 fprintf(debugFP, ": chases\n");
2557 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2558 for(j=0; j<chaseStackPointer; j++) {
2559 preyStack[j].rank = chaseStack[j].rt;
2560 preyStack[j].file = chaseStack[j].ft;
2562 preyStackPointer = chaseStackPointer;
2565 for(j=0; j<chaseStackPointer; j++) {
2566 for(k=0; k<preyStackPointer; k++) {
2567 // search the victim of each chase move on the preyStack (first occurrence)
2568 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2569 if(k < tail) break; // piece was already identified as still being chased
2570 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2571 preyStack[tail] = preyStack[k]; // by swapping
2572 preyStack[k] = preyStack[preyStackPointer];
2578 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2579 if(appData.debugMode) { int n;
2580 for(n=0; n<preyStackPointer; n++)
2581 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2582 fprintf(debugFP, "always chased upto ply %d\n", i);
2584 // now adjust the location of the chased pieces according to opponent move
2585 for(j=0; j<preyStackPointer; j++) {
2586 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2587 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2588 preyStack[j].rank = moveList[i+1][3]-ONE;
2589 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2594 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2595 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the