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[] = "AKCD.QGH.JQL.NO.KK....Q..Z";
240 // 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 "
241 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 };
242 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 };
243 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 };
244 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 };
246 int rot[][4] = { // rotation matrices for each direction
258 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
264 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
266 char buf[80], *p = desc;
267 int mine, his, dir, bit, occup, i;
268 if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
269 while(*p) { // more moves to go
270 int expo = 1, dx, dy, x, y, mode, dirSet, ds2, retry=0, initial=0, jump=1, skip = 0;
272 if(*p == 'i') initial = 1, desc = ++p;
273 while(islower(*p)) p++; // skip prefixes
274 if(!isupper(*p)) return; // syntax error: no atom
275 dx = xStep[*p-'A'] - '0';// step vector of atom
276 dy = yStep[*p-'A'] - '0';
277 dirSet = 0; // build direction set based on atom symmetry
278 switch(symmetry[*p-'A']) {
279 case 'B': expo = 0; // bishop, slide
280 case 'F': // diagonal atom (degenerate 4-fold)
281 if(tx < 0) { // for continuation legs relative directions are orthogonal!
282 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
283 int b = dirs1[*desc-'a']; // use wide version
284 if( islower(desc[1]) &&
285 ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim)
286 b = dirs1[*desc-'a'] & dirs1[desc[1]-'a']; // intersect wide & perp wide
291 dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
294 case 'R': expo = 0; // rook, slide
295 case 'W': // orthogonal atom (non-deg 4-fold)
296 while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
297 dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
298 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
300 case 'N': // oblique atom (degenerate 8-fold)
301 if(tx < 0) { // for continuation legs relative directions are non-degenerate!
302 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
303 int b = dirs2[*desc-'a']; // when alone, use narrow version
304 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
305 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
306 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
307 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
312 if(!dirSet) dirSet = 0xFF;
315 case 'Q': expo = 0; // queen, slide
316 case 'K': // non-deg (pseudo) 8-fold
317 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
318 int b = dirs4[*desc-'a']; // when alone, use narrow version
319 if(desc[1] == *desc) desc++; // doubling forces alone
320 else if(islower(desc[1]) && i < '4'
321 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
322 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
327 if(!dirSet) dirSet = 0xFF;
328 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
329 ds2 = dirSet & 0xAA; // extract diagonal directions
330 if(dirSet &= 0x55) // start with orthogonal moves, if present
331 retry = 1; // and schedule the diagonal moves for later
332 else dx = 1, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
333 break; // should not have direction indicators
334 default: return; // syntax error: invalid atom
336 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
337 mode = 0; // build mode mask
338 if(*desc == 'm') mode |= 4, desc++;
339 if(*desc == 'c') mode |= his, desc++;
340 if(*desc == 'd') mode |= mine, desc++;
341 if(*desc == 'e') mode |= 8, desc++;
342 if(*desc == 'p') mode |= 32, desc++;
343 if(*desc == 'g') mode |= 64, desc++;
344 if(*desc == 'o') mode |= 128, desc++;
345 if(*desc == 'y') mode |= 512, desc++;
346 if(*desc == 'n') jump = 0, desc++;
347 while(*desc == 'j') jump++, desc++;
348 if(*desc == 'a') cont = ++desc;
349 if(isdigit(*++p)) expo = atoi(p++); // read exponent
350 if(expo > 9) p++; // allow double-digit
351 desc = p; // this is start of next move
352 if(initial && (board[r][f] != initialPosition[r][f] ||
353 r == 0 && board[TOUCHED_W] & 1<<f ||
354 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
355 if(expo > 1 && dx == 0 && dy == 0) { // castling indicated by O + number
359 if(!(mode & 15)) mode = his + 4; // no mode spec, use default = mc
361 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
362 if(mode & 64 + 512) {
363 mode |= 256; // and 'g' too, but converts leaper <-> slider
364 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
365 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
366 while(islower(*cont)) cont++; // skip to atom
367 *cont = upgrade[*cont-'A']; // replace atom, BRQ <-> FWK
368 if(expo == 1) *++cont = '0'; // turn other leapers into riders
369 *++cont = '\0'; // make sure any old range is stripped off
370 cont = buf; // use modified string for continuation leg
372 if(!(mode & 0x30F)) mode = his + 0x104; // and default = mcp
374 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
376 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
377 int i = expo, j = skip, hop = mode, vx, vy;
378 if(!(bit & dirSet)) continue; // does not move in this direction
379 if(dy != 1) j = 0; //
380 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
381 vy = dx*rot[dir][2] + dy*rot[dir][3];
382 if(tx < 0) x = f, y = r; // start square
383 else x = tx, y = ty; // from previous to-square if continuation
385 x += vx; y += vy; // step to next square
386 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
387 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT; else break; }
388 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT; else break; }
389 if(j) { j--; continue; } // skip irrespective of occupation
390 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
391 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
392 if(x == f && y == r) occup = 4; else // start square counts as empty
393 if(board[y][x] < BlackPawn) occup = 0x101; else
394 if(board[y][x] < EmptySquare) occup = 0x102; else
396 if(cont) { // non-final leg
397 if(occup & mode) { // valid intermediate square, do continuation
398 if(occup & mode & 0x104) // no side effects, merge legs to one move
399 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
400 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
402 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
403 if(cnt) { // and if there are
404 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
406 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
411 if(occup != 4) break; // occupied squares always terminate the leg
414 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
415 if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
416 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
418 if(mode & 16) { // castling
419 i = 2; // kludge to elongate move indefinitely
420 if(occup == 4) continue; // skip empty squares
421 if(x == BOARD_LEFT && board[y][x] == initialPosition[y][x]) // reached initial corner piece
422 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
423 if(x == BOARD_RGHT-1 && board[y][x] == initialPosition[y][x])
424 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
427 if(occup & mode) cb(board, flags, NormalMove, r, f, y, x, cl); // allowed, generate
428 if(occup != 4) break; // not valid transit square
431 dx = dy = 1; dirSet = ds2; // prepare for diagonal moves of K,Q
432 } while(retry-- && ds2); // and start doing them
433 if(tx >= 0) break; // don't do other atoms in continuation legs
437 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
440 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
445 if (rt >= BOARD_HEIGHT) break;
446 if (SameColor(board[rf][ff], board[rt][ft])) break;
447 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
448 if (board[rt][ft] != EmptySquare) break;
453 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
459 if (SameColor(board[rf][ff], board[rt][ft])) break;
460 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
461 if (board[rt][ft] != EmptySquare) break;
466 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
468 SlideForward(board, flags, rf, ff, callback, closure);
469 SlideBackward(board, flags, rf, ff, callback, closure);
473 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
475 int i, s, rt = rf, ft;
476 for(s = -1; s <= 1; s+= 2) {
479 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
480 if (SameColor(board[rf][ff], board[rt][ft])) break;
481 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
482 if (board[rt][ft] != EmptySquare) break;
488 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
491 for(s = -1; s <= 1; s+= 2) {
495 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
496 if (SameColor(board[rf][ff], board[rt][ft])) break;
497 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
498 if (board[rt][ft] != EmptySquare) break;
504 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
507 for(s = -1; s <= 1; s+= 2) {
511 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
512 if (SameColor(board[rf][ff], board[rt][ft])) break;
513 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
514 if (board[rt][ft] != EmptySquare) break;
520 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
522 SlideVertical(board, flags, rf, ff, callback, closure);
523 SlideSideways(board, flags, rf, ff, callback, closure);
527 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
529 SlideDiagForward(board, flags, rf, ff, callback, closure);
530 SlideDiagBackward(board, flags, rf, ff, callback, closure);
534 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
535 { // Lion-like move of Horned Falcon and Souring Eagle
536 int ft = ff + dx, rt = rf + dy;
537 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
539 if (!SameColor(board[rf][ff], board[rt][ft]))
540 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
543 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
545 if (!SameColor(board[rf][ff], board[rt][ft]))
546 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
547 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
548 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
553 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
555 int ft = ff, rt = rf + 1;
556 if (rt >= BOARD_HEIGHT) return;
557 if (SameColor(board[rf][ff], board[rt][ft])) return;
558 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
562 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
564 int ft = ff, rt = rf - 1;
566 if (SameColor(board[rf][ff], board[rt][ft])) return;
567 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
571 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
575 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
576 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
578 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
579 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
583 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
586 if (rt >= BOARD_HEIGHT) return;
588 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
589 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
591 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
592 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
596 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
601 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
602 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
604 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
605 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
609 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
611 StepForward(board, flags, rf, ff, callback, closure);
612 StepBackward(board, flags, rf, ff, callback, closure);
616 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
618 StepDiagForward(board, flags, rf, ff, callback, closure);
619 StepDiagBackward(board, flags, rf, ff, callback, closure);
623 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
625 StepVertical(board, flags, rf, ff, callback, closure);
626 StepSideways(board, flags, rf, ff, callback, closure);
630 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
633 for (i = -1; i <= 1; i += 2)
634 for (j = -1; j <= 1; j += 2)
635 for (s = 1; s <= 2; s++) {
638 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
639 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
640 && !SameColor(board[rf][ff], board[rt][ft]))
641 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
645 /* Call callback once for each pseudo-legal move in the given
646 position, except castling moves. A move is pseudo-legal if it is
647 legal, or if it would be legal except that it leaves the king in
648 check. In the arguments, epfile is EP_NONE if the previous move
649 was not a double pawn push, or the file 0..7 if it was, or
650 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
651 Promotion moves generated are to Queen only.
654 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
655 // speed: only do moves with this piece type
658 int i, j, d, s, fs, rs, rt, ft, m;
659 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
660 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
662 for (rf = 0; rf < BOARD_HEIGHT; rf++)
663 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
666 if(board[rf][ff] == EmptySquare) continue;
667 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
668 m = 0; piece = board[rf][ff];
669 if(PieceToChar(piece) == '~')
670 piece = (ChessSquare) ( DEMOTED piece );
671 if(filter != EmptySquare && piece != filter) continue;
672 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
673 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
676 if(IS_SHOGI(gameInfo.variant))
677 piece = (ChessSquare) ( SHOGI piece );
679 switch ((int)piece) {
680 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
682 /* can't happen ([HGM] except for faries...) */
686 if(gameInfo.variant == VariantXiangqi) {
687 /* [HGM] capture and move straight ahead in Xiangqi */
688 if (rf < BOARD_HEIGHT-1 &&
689 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
690 callback(board, flags, NormalMove,
691 rf, ff, rf + 1, ff, closure);
693 /* and move sideways when across the river */
694 for (s = -1; s <= 1; s += 2) {
695 if (rf >= BOARD_HEIGHT>>1 &&
696 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
697 !WhitePiece(board[rf][ff+s]) ) {
698 callback(board, flags, NormalMove,
699 rf, ff, rf, ff+s, closure);
704 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
705 callback(board, flags,
706 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
707 rf, ff, rf + 1, ff, closure);
709 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
710 gameInfo.variant != VariantShatranj && /* [HGM] */
711 gameInfo.variant != VariantCourier && /* [HGM] */
712 board[rf+2][ff] == EmptySquare ) {
713 callback(board, flags, NormalMove,
714 rf, ff, rf+2, ff, closure);
716 for (s = -1; s <= 1; s += 2) {
717 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
718 ((flags & F_KRIEGSPIEL_CAPTURE) ||
719 BlackPiece(board[rf + 1][ff + s]))) {
720 callback(board, flags,
721 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
722 rf, ff, rf + 1, ff + s, closure);
724 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
725 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
726 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
727 board[rf][ff + s] == BlackPawn &&
728 board[rf+1][ff + s] == EmptySquare) {
729 callback(board, flags, WhiteCapturesEnPassant,
730 rf, ff, rf+1, ff + s, closure);
737 if(gameInfo.variant == VariantXiangqi) {
738 /* [HGM] capture straight ahead in Xiangqi */
739 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
740 callback(board, flags, NormalMove,
741 rf, ff, rf - 1, ff, closure);
743 /* and move sideways when across the river */
744 for (s = -1; s <= 1; s += 2) {
745 if (rf < BOARD_HEIGHT>>1 &&
746 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
747 !BlackPiece(board[rf][ff+s]) ) {
748 callback(board, flags, NormalMove,
749 rf, ff, rf, ff+s, closure);
754 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
755 callback(board, flags,
756 rf <= promoRank ? BlackPromotion : NormalMove,
757 rf, ff, rf - 1, ff, closure);
759 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
760 gameInfo.variant != VariantShatranj && /* [HGM] */
761 gameInfo.variant != VariantCourier && /* [HGM] */
762 board[rf-2][ff] == EmptySquare) {
763 callback(board, flags, NormalMove,
764 rf, ff, rf-2, ff, closure);
766 for (s = -1; s <= 1; s += 2) {
767 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
768 ((flags & F_KRIEGSPIEL_CAPTURE) ||
769 WhitePiece(board[rf - 1][ff + s]))) {
770 callback(board, flags,
771 rf <= promoRank ? BlackPromotion : NormalMove,
772 rf, ff, rf - 1, ff + s, closure);
774 if (rf < BOARD_HEIGHT>>1) {
775 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
776 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
777 board[rf][ff + s] == WhitePawn &&
778 board[rf-1][ff + s] == EmptySquare) {
779 callback(board, flags, BlackCapturesEnPassant,
780 rf, ff, rf-1, ff + s, closure);
790 for (i = -1; i <= 1; i += 2)
791 for (j = -1; j <= 1; j += 2)
792 for (s = 1; s <= 2; s++) {
795 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
796 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
797 && !SameColor(board[rf][ff], board[rt][ft]))
798 callback(board, flags, NormalMove,
799 rf, ff, rt, ft, closure);
803 case SHOGI WhiteKnight:
804 for (s = -1; s <= 1; s += 2) {
805 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
806 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
807 callback(board, flags, NormalMove,
808 rf, ff, rf + 2, ff + s, closure);
813 case SHOGI BlackKnight:
814 for (s = -1; s <= 1; s += 2) {
815 if (rf > 1 && 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);
825 for (d = 0; d <= 1; d++)
826 for (s = -1; s <= 1; s += 2) {
829 rt = rf + (i * s) * d;
830 ft = ff + (i * s) * (1 - d);
831 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
832 if (m == 0 && board[rt][ft] == EmptySquare)
833 callback(board, flags, NormalMove,
834 rf, ff, rt, ft, closure);
835 if (m == 1 && board[rt][ft] != EmptySquare &&
836 !SameColor(board[rf][ff], board[rt][ft]) )
837 callback(board, flags, NormalMove,
838 rf, ff, rt, ft, closure);
839 if (board[rt][ft] != EmptySquare && m++) break;
844 /* Gold General (and all its promoted versions) . First do the */
845 /* diagonal forward steps, then proceed as normal Wazir */
846 case SHOGI (PROMOTED WhitePawn):
847 if(gameInfo.variant == VariantShogi) goto WhiteGold;
848 case SHOGI (PROMOTED BlackPawn):
849 if(gameInfo.variant == VariantShogi) goto BlackGold;
850 SlideVertical(board, flags, rf, ff, callback, closure);
853 case SHOGI (PROMOTED WhiteKnight):
854 if(gameInfo.variant == VariantShogi) goto WhiteGold;
855 case SHOGI BlackDrunk:
856 case SHOGI BlackAlfil:
857 Ferz(board, flags, rf, ff, callback, closure);
858 StepSideways(board, flags, rf, ff, callback, closure);
859 StepBackward(board, flags, rf, ff, callback, closure);
862 case SHOGI (PROMOTED BlackKnight):
863 if(gameInfo.variant == VariantShogi) goto BlackGold;
864 case SHOGI WhiteDrunk:
865 case SHOGI WhiteAlfil:
866 Ferz(board, flags, rf, ff, callback, closure);
867 StepSideways(board, flags, rf, ff, callback, closure);
868 StepForward(board, flags, rf, ff, callback, closure);
872 case SHOGI WhiteStag:
873 case SHOGI BlackStag:
874 if(gameInfo.variant == VariantShogi) goto BlackGold;
875 SlideVertical(board, flags, rf, ff, callback, closure);
876 Ferz(board, flags, rf, ff, callback, closure);
877 StepSideways(board, flags, rf, ff, callback, closure);
880 case SHOGI (PROMOTED WhiteQueen):
881 case SHOGI WhiteTokin:
882 case SHOGI WhiteWazir:
884 StepDiagForward(board, flags, rf, ff, callback, closure);
885 Wazir(board, flags, rf, ff, callback, closure);
888 case SHOGI (PROMOTED BlackQueen):
889 case SHOGI BlackTokin:
890 case SHOGI BlackWazir:
892 StepDiagBackward(board, flags, rf, ff, callback, closure);
893 Wazir(board, flags, rf, ff, callback, closure);
898 Wazir(board, flags, rf, ff, callback, closure);
901 case SHOGI WhiteMarshall:
902 case SHOGI BlackMarshall:
903 Ferz(board, flags, rf, ff, callback, closure);
904 for (d = 0; d <= 1; d++)
905 for (s = -2; s <= 2; s += 4) {
907 ft = ff + s * (1 - d);
908 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
909 if (!SameColor(board[rf][ff], board[rt][ft]) )
910 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
914 case SHOGI WhiteAngel:
915 case SHOGI BlackAngel:
916 Wazir(board, flags, rf, ff, callback, closure);
920 /* [HGM] support Shatranj pieces */
921 for (rs = -1; rs <= 1; rs += 2)
922 for (fs = -1; fs <= 1; fs += 2) {
925 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
926 && ( gameInfo.variant != VariantXiangqi ||
927 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
929 && !SameColor(board[rf][ff], board[rt][ft]))
930 callback(board, flags, NormalMove,
931 rf, ff, rt, ft, closure);
932 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
933 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
934 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
936 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
937 && !SameColor(board[rf][ff], board[rt][ft]))
938 callback(board, flags, NormalMove,
939 rf, ff, rt, ft, closure);
941 if(gameInfo.variant == VariantSpartan)
942 for(fs = -1; fs <= 1; fs += 2) {
944 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
945 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
949 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
952 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
953 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
954 for (s = -2; s <= 2; s += 4) {
956 ft = ff + s * (1 - d);
957 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
958 if (SameColor(board[rf][ff], board[rt][ft])) continue;
959 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
962 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
963 case SHOGI WhiteCardinal:
964 case SHOGI BlackCardinal:
965 case SHOGI WhitePCardinal:
966 case SHOGI BlackPCardinal:
968 Bishop(board, flags, rf, ff, callback, closure);
969 Wazir(board, flags, rf, ff, callback, closure);
972 /* Capablanca Archbishop continues as Knight */
975 Knight(board, flags, rf, ff, callback, closure);
977 /* Shogi Bishops are ordinary Bishops */
978 case SHOGI WhiteBishop:
979 case SHOGI BlackBishop:
980 case SHOGI WhitePBishop:
981 case SHOGI BlackPBishop:
984 Bishop(board, flags, rf, ff, callback, closure);
987 /* Shogi Lance is unlike anything, and asymmetric at that */
988 case SHOGI WhiteQueen:
989 if(gameInfo.variant == VariantChu) goto doQueen;
993 if (rt >= BOARD_HEIGHT) break;
994 if (SameColor(board[rf][ff], board[rt][ft])) break;
995 callback(board, flags, NormalMove,
996 rf, ff, rt, ft, closure);
997 if (board[rt][ft] != EmptySquare) break;
1001 case SHOGI BlackQueen:
1002 if(gameInfo.variant == VariantChu) goto doQueen;
1007 if (SameColor(board[rf][ff], board[rt][ft])) break;
1008 callback(board, flags, NormalMove,
1009 rf, ff, rt, ft, closure);
1010 if (board[rt][ft] != EmptySquare) break;
1014 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1017 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1018 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1019 for (s = -2; s <= 2; s += 4) {
1021 ft = ff + s * (1 - d);
1022 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1023 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1024 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1025 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1027 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1028 Wazir(board, flags, rf, ff, callback, closure);
1030 Rook(board, flags, rf, ff, callback, closure);
1033 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1034 case SHOGI WhiteDragon:
1035 case SHOGI BlackDragon:
1036 case SHOGI WhitePDragon:
1037 case SHOGI BlackPDragon:
1039 Rook(board, flags, rf, ff, callback, closure);
1040 Ferz(board, flags, rf, ff, callback, closure);
1044 /* Capablanca Chancellor sets flag to continue as Knight */
1047 Rook(board, flags, rf, ff, callback, closure);
1048 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1049 Ferz(board, flags, rf, ff, callback, closure);
1051 Knight(board, flags, rf, ff, callback, closure);
1054 /* Shogi Rooks are ordinary Rooks */
1055 case SHOGI WhiteRook:
1056 case SHOGI BlackRook:
1057 case SHOGI WhitePRook:
1058 case SHOGI BlackPRook:
1061 Rook(board, flags, rf, ff, callback, closure);
1066 case SHOGI WhiteMother:
1067 case SHOGI BlackMother:
1069 Rook(board, flags, rf, ff, callback, closure);
1070 Bishop(board, flags, rf, ff, callback, closure);
1073 case SHOGI WhitePawn:
1074 StepForward(board, flags, rf, ff, callback, closure);
1077 case SHOGI BlackPawn:
1078 StepBackward(board, flags, rf, ff, callback, closure);
1082 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1083 case SHOGI WhiteFerz:
1084 Ferz(board, flags, rf, ff, callback, closure);
1085 StepForward(board, flags, rf, ff, callback, closure);
1089 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1090 case SHOGI BlackFerz:
1091 StepBackward(board, flags, rf, ff, callback, closure);
1095 /* [HGM] support Shatranj pieces */
1096 Ferz(board, flags, rf, ff, callback, closure);
1101 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1104 case SHOGI WhiteMonarch:
1105 case SHOGI BlackMonarch:
1106 case SHOGI WhiteKing:
1107 case SHOGI BlackKing:
1110 Ferz(board, flags, rf, ff, callback, closure);
1111 Wazir(board, flags, rf, ff, callback, closure);
1114 case WhiteNightrider:
1115 case BlackNightrider:
1116 for (i = -1; i <= 1; i += 2)
1117 for (j = -1; j <= 1; j += 2)
1118 for (s = 1; s <= 2; s++) { int k;
1121 ft = ff + k*j*(3-s);
1122 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1123 if (SameColor(board[rf][ff], board[rt][ft])) break;
1124 callback(board, flags, NormalMove,
1125 rf, ff, rt, ft, closure);
1126 if (board[rt][ft] != EmptySquare) break;
1132 Bishop(board, flags, rf, ff, callback, closure);
1133 Rook(board, flags, rf, ff, callback, closure);
1134 Knight(board, flags, rf, ff, callback, closure);
1137 // Use Lance as Berolina / Spartan Pawn.
1139 if(gameInfo.variant == VariantSuper) goto Amazon;
1140 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1141 callback(board, flags,
1142 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1143 rf, ff, rf + 1, ff, closure);
1144 for (s = -1; s <= 1; s += 2) {
1145 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1146 callback(board, flags,
1147 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1148 rf, ff, rf + 1, ff + s, closure);
1149 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1150 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1155 if(gameInfo.variant == VariantSuper) goto Amazon;
1156 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1157 callback(board, flags,
1158 rf <= promoRank ? BlackPromotion : NormalMove,
1159 rf, ff, rf - 1, ff, closure);
1160 for (s = -1; s <= 1; s += 2) {
1161 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1162 callback(board, flags,
1163 rf <= promoRank ? BlackPromotion : NormalMove,
1164 rf, ff, rf - 1, ff + s, closure);
1165 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1166 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1170 case SHOGI WhiteNothing:
1171 case SHOGI BlackNothing:
1172 case SHOGI WhiteLion:
1173 case SHOGI BlackLion:
1176 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1177 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1178 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1179 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1180 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1181 rf, ff, rt, ft, closure);
1186 case SHOGI WhiteFalcon:
1187 case SHOGI BlackFalcon:
1188 case SHOGI WhitePDagger:
1189 case SHOGI BlackPDagger:
1190 SlideSideways(board, flags, rf, ff, callback, closure);
1191 StepVertical(board, flags, rf, ff, callback, closure);
1194 case SHOGI WhiteCobra:
1195 case SHOGI BlackCobra:
1196 StepVertical(board, flags, rf, ff, callback, closure);
1199 case SHOGI (PROMOTED WhiteFerz):
1200 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1201 case SHOGI (PROMOTED BlackFerz):
1202 if(gameInfo.variant == VariantShogi) goto BlackGold;
1203 case SHOGI WhitePSword:
1204 case SHOGI BlackPSword:
1205 SlideVertical(board, flags, rf, ff, callback, closure);
1206 StepSideways(board, flags, rf, ff, callback, closure);
1209 case SHOGI WhiteUnicorn:
1210 case SHOGI BlackUnicorn:
1211 Ferz(board, flags, rf, ff, callback, closure);
1212 StepVertical(board, flags, rf, ff, callback, closure);
1215 case SHOGI WhiteMan:
1216 StepDiagForward(board, flags, rf, ff, callback, closure);
1217 StepVertical(board, flags, rf, ff, callback, closure);
1220 case SHOGI BlackMan:
1221 StepDiagBackward(board, flags, rf, ff, callback, closure);
1222 StepVertical(board, flags, rf, ff, callback, closure);
1225 case SHOGI WhiteHCrown:
1226 case SHOGI BlackHCrown:
1227 Bishop(board, flags, rf, ff, callback, closure);
1228 SlideSideways(board, flags, rf, ff, callback, closure);
1231 case SHOGI WhiteCrown:
1232 case SHOGI BlackCrown:
1233 Bishop(board, flags, rf, ff, callback, closure);
1234 SlideVertical(board, flags, rf, ff, callback, closure);
1237 case SHOGI WhiteHorned:
1238 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1239 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1240 if(killX >= 0) break;
1241 Bishop(board, flags, rf, ff, callback, closure);
1242 SlideSideways(board, flags, rf, ff, callback, closure);
1243 SlideBackward(board, flags, rf, ff, callback, closure);
1246 case SHOGI BlackHorned:
1247 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1248 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1249 if(killX >= 0) break;
1250 Bishop(board, flags, rf, ff, callback, closure);
1251 SlideSideways(board, flags, rf, ff, callback, closure);
1252 SlideForward(board, flags, rf, ff, callback, closure);
1255 case SHOGI WhiteEagle:
1256 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1257 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1258 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1259 if(killX >= 0) break;
1260 Rook(board, flags, rf, ff, callback, closure);
1261 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1264 case SHOGI BlackEagle:
1265 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1266 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1267 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1268 if(killX >= 0) break;
1269 Rook(board, flags, rf, ff, callback, closure);
1270 SlideDiagForward(board, flags, rf, ff, callback, closure);
1273 case SHOGI WhiteDolphin:
1274 case SHOGI BlackHorse:
1275 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1276 SlideVertical(board, flags, rf, ff, callback, closure);
1279 case SHOGI BlackDolphin:
1280 case SHOGI WhiteHorse:
1281 SlideDiagForward(board, flags, rf, ff, callback, closure);
1282 SlideVertical(board, flags, rf, ff, callback, closure);
1285 case SHOGI WhiteLance:
1286 SlideForward(board, flags, rf, ff, callback, closure);
1289 case SHOGI BlackLance:
1290 SlideBackward(board, flags, rf, ff, callback, closure);
1293 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1297 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1310 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1311 Board xqCheckers, nullBoard;
1313 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1314 int rf, int ff, int rt, int ft,
1318 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1320 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1322 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1324 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1326 if (!(flags & F_IGNORE_CHECK) ) {
1327 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1330 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1331 kings += (board[r][f] == BlackKing);
1335 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1337 check = CheckTest(board, flags, rf, ff, rt, ft,
1338 kind == WhiteCapturesEnPassant ||
1339 kind == BlackCapturesEnPassant);
1340 if(promo) board[rf][ff] = BlackLance;
1343 if (flags & F_ATOMIC_CAPTURE) {
1344 if (board[rt][ft] != EmptySquare ||
1345 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1347 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1348 if (board[rf][ff] == king) return;
1349 for (r = rt-1; r <= rt+1; r++) {
1350 for (f = ft-1; f <= ft+1; f++) {
1351 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1352 board[r][f] == king) return;
1357 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1364 int captures; // [HGM] losers
1365 } LegalityTestClosure;
1368 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1369 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1370 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1371 moves that would destroy your own king. The CASTLE_OK flags are
1372 true if castling is not yet ruled out by a move of the king or
1373 rook. Return TRUE if the player on move is currently in check and
1374 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1376 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1379 int ff, ft, k, left, right, swap;
1380 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1381 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1382 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1387 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1388 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1389 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1391 if (inCheck) return TRUE;
1393 /* Generate castling moves */
1394 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1395 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1398 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1399 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1401 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1402 if ((flags & F_WHITE_ON_MOVE) &&
1403 (flags & F_WHITE_KCASTLE_OK) &&
1404 board[0][ff] == wKing &&
1405 board[0][ff + 1] == EmptySquare &&
1406 board[0][ff + 2] == EmptySquare &&
1407 board[0][BOARD_RGHT-3] == EmptySquare &&
1408 board[0][BOARD_RGHT-2] == EmptySquare &&
1409 board[0][BOARD_RGHT-1] == WhiteRook &&
1410 castlingRights[0] != NoRights && /* [HGM] check rights */
1411 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1413 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1414 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1415 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1416 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1418 callback(board, flags,
1419 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1420 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1422 if ((flags & F_WHITE_ON_MOVE) &&
1423 (flags & F_WHITE_QCASTLE_OK) &&
1424 board[0][ff] == wKing &&
1425 board[0][ff - 1] == EmptySquare &&
1426 board[0][ff - 2] == EmptySquare &&
1427 board[0][BOARD_LEFT+2] == EmptySquare &&
1428 board[0][BOARD_LEFT+1] == EmptySquare &&
1429 board[0][BOARD_LEFT+0] == WhiteRook &&
1430 castlingRights[1] != NoRights && /* [HGM] check rights */
1431 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1433 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1434 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1435 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1437 callback(board, flags,
1438 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1439 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1441 if (!(flags & F_WHITE_ON_MOVE) &&
1442 (flags & F_BLACK_KCASTLE_OK) &&
1443 board[BOARD_HEIGHT-1][ff] == bKing &&
1444 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1445 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1446 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1447 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1448 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1449 castlingRights[3] != NoRights && /* [HGM] check rights */
1450 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1452 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1453 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1454 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1455 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1457 callback(board, flags,
1458 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1459 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1461 if (!(flags & F_WHITE_ON_MOVE) &&
1462 (flags & F_BLACK_QCASTLE_OK) &&
1463 board[BOARD_HEIGHT-1][ff] == bKing &&
1464 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1465 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1466 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1467 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1468 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1469 castlingRights[4] != NoRights && /* [HGM] check rights */
1470 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1472 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1473 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1474 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1476 callback(board, flags,
1477 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1478 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1482 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1484 /* generate all potential FRC castling moves (KxR), ignoring flags */
1485 /* [HGM] test if the Rooks we find have castling rights */
1486 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1489 if ((flags & F_WHITE_ON_MOVE) != 0) {
1490 ff = castlingRights[2]; /* King file if we have any rights */
1491 if(ff != NoRights && board[0][ff] == WhiteKing) {
1492 if (appData.debugMode) {
1493 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1494 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1496 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1498 right = BOARD_RGHT-2;
1499 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1500 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1501 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1502 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1503 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1504 if(ft != NoRights && board[0][ft] == WhiteRook) {
1505 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1506 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1509 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1510 left = BOARD_LEFT+2;
1512 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1513 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1514 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1515 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1516 if(ff > BOARD_LEFT+2)
1517 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1518 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1519 if(ft != NoRights && board[0][ft] == WhiteRook) {
1520 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1521 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1525 ff = castlingRights[5]; /* King file if we have any rights */
1526 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1527 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1529 right = BOARD_RGHT-2;
1530 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1531 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1532 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1533 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1534 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1535 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1536 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1537 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1540 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1541 left = BOARD_LEFT+2;
1543 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1544 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1545 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1546 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1547 if(ff > BOARD_LEFT+2)
1548 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1549 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1550 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1551 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1552 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1569 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1570 int rf, int ff, int rt, int ft,
1575 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1577 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1579 if (rt == cl->rking && ft == cl->fking) {
1580 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1582 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1584 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1585 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1586 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1590 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1591 he leave himself in check? Or if rf == -1, is the player on move
1592 in check now? enPassant must be TRUE if the indicated move is an
1593 e.p. capture. The possibility of castling out of a check along the
1594 back rank is not accounted for (i.e., we still return nonzero), as
1595 this is illegal anyway. Return value is the number of times the
1596 king is in check. */
1598 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1600 CheckTestClosure cl;
1601 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1602 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1603 /* Suppress warnings on uninitialized variables */
1605 if(gameInfo.variant == VariantXiangqi)
1606 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1607 if(gameInfo.variant == VariantKnightmate)
1608 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1609 if(gameInfo.variant == VariantChu) { // strictly speaking this is not needed, as Chu officially has no check
1610 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1611 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1612 if(board[r][f] == k || board[r][f] == prince) {
1613 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1614 king = board[r][f]; // remember hich one we had
1621 captured = board[rf][ft];
1622 board[rf][ft] = EmptySquare;
1624 captured = board[rt][ft];
1625 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; }
1627 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1628 board[rt][ft] = board[rf][ff];
1629 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1631 ep = board[EP_STATUS];
1632 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1633 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1634 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1635 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1636 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1637 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1641 /* For compatibility with ICS wild 9, we scan the board in the
1642 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1643 and we test only whether that one is in check. */
1644 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1645 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1646 if (board[cl.rking][cl.fking] == king) {
1648 if(gameInfo.variant == VariantXiangqi) {
1649 /* [HGM] In Xiangqi opposing Kings means check as well */
1651 dir = (king >= BlackPawn) ? -1 : 1;
1652 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1653 board[i][cl.fking] == EmptySquare; i+=dir );
1654 if(i>=0 && i<BOARD_HEIGHT &&
1655 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1658 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1659 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1660 goto undo_move; /* 2-level break */
1667 if(rf != DROP_RANK) // [HGM] drop
1668 board[rf][ff] = board[rt][ft];
1670 board[rf][ft] = captured;
1671 board[rt][ft] = EmptySquare;
1673 if(killX >= 0) board[killY][killX] = trampled;
1674 board[rt][ft] = captured;
1676 board[EP_STATUS] = ep;
1679 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1683 HasLion (Board board, int flags)
1685 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1687 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1688 if(board[r][f] == lion) return 1;
1693 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1694 { // [HGM] put drop legality testing in separate routine for clarity
1696 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1697 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1698 n = PieceToNumber(piece);
1699 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1700 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1701 return ImpossibleMove; // piece not available
1702 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1703 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1704 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1705 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1706 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1707 if(piece == WhitePawn || piece == BlackPawn) {
1708 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1709 for(r=1; r<BOARD_HEIGHT-1; r++)
1710 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1711 // should still test if we mate with this Pawn
1713 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1714 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1716 if( (piece == WhitePawn || piece == BlackPawn) &&
1717 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1718 return IllegalMove; /* no pawn drops on 1st/8th */
1720 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1721 if (!(flags & F_IGNORE_CHECK) &&
1722 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1723 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1726 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1727 int rf, int ff, int rt, int ft,
1731 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1733 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1735 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1736 cl->captures++; // [HGM] losers: count legal captures
1737 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1742 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1744 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1746 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1747 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1748 piece = filterPiece = board[rf][ff];
1749 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1751 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1752 /* (perhaps we should disallow moves that obviously leave us in check?) */
1753 if((piece == WhiteFalcon || piece == BlackFalcon ||
1754 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1755 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1759 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1760 cl.ft = fFilter = ft;
1761 cl.kind = IllegalMove;
1762 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1763 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1764 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1765 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1766 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1767 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1769 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1770 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1771 if(board[rf][ff] < BlackPawn) { // white
1772 if(rf != 0) return IllegalMove; // must be on back rank
1773 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1774 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1775 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1776 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1778 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1779 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1780 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1781 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1782 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1785 if(gameInfo.variant == VariantChu) {
1786 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1787 if(promoChar != '+')
1788 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1789 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1790 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1792 if(gameInfo.variant == VariantShogi) {
1793 /* [HGM] Shogi promotions. '=' means defer */
1794 if(rf != DROP_RANK && cl.kind == NormalMove) {
1795 ChessSquare piece = board[rf][ff];
1797 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1798 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1799 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1800 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1801 promoChar = '+'; // allowed ICS notations
1802 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1803 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1804 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1805 else if(flags & F_WHITE_ON_MOVE) {
1806 if( (int) piece < (int) WhiteWazir &&
1807 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1808 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1809 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1810 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1811 else /* promotion optional, default is defer */
1812 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1813 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1815 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1816 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1817 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1818 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1819 else /* promotion optional, default is defer */
1820 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1821 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1825 if (promoChar != NULLCHAR) {
1826 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1827 ChessSquare piece = board[rf][ff];
1828 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1829 // should test if in zone, really
1830 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1832 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1834 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1835 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1836 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1837 if(piece == EmptySquare)
1838 cl.kind = ImpossibleMove; // non-existing piece
1839 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1840 cl.kind = IllegalMove; // no two Lions
1841 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1842 if(promoChar != PieceToChar(BlackKing)) {
1843 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1844 if(piece == BlackLance) cl.kind = ImpossibleMove;
1845 } else { // promotion to King allowed only if we do not have two yet
1846 int r, f, kings = 0;
1847 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1848 if(kings == 2) cl.kind = IllegalMove;
1850 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1851 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1852 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1853 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1854 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1855 cl.kind = IllegalMove; // promotion to King usually not allowed
1857 cl.kind = IllegalMove;
1867 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1868 int rf, int ff, int rt, int ft,
1872 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1874 register MateTestClosure *cl = (MateTestClosure *) closure;
1879 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1881 MateTest (Board board, int flags)
1884 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1885 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1887 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1888 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1889 nrKing += (board[r][f] == king); // stm has king
1890 if( board[r][f] != EmptySquare ) {
1891 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1896 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1897 case VariantShatranj:
1898 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1902 if(nrKing == 0) return MT_NOKING;
1905 if(myPieces == 1) return MT_BARE;
1908 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1909 // [HGM] 3check: yet to do!
1911 return inCheck ? MT_CHECK : MT_NONE;
1913 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1914 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1915 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1916 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1917 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1918 if(board[n][holdings] != EmptySquare) {
1919 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1920 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1923 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1924 return myPieces == hisPieces ? MT_STALEMATE :
1925 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1926 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1927 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1929 return inCheck ? MT_CHECKMATE
1930 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1931 MT_STAINMATE : MT_STALEMATE;
1936 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1937 int rf, int ff, int rt, int ft,
1941 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1943 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1944 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1946 // [HGM] wild: for wild-card pieces rt and rf are dummies
1947 if(piece == WhiteFalcon || piece == BlackFalcon ||
1948 piece == WhiteCobra || piece == BlackCobra)
1951 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1952 || PieceToChar(board[rf][ff]) == '~'
1953 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1955 (cl->rfIn == -1 || cl->rfIn == rf) &&
1956 (cl->ffIn == -1 || cl->ffIn == ff) &&
1957 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1958 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1960 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1963 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1964 // [HGM] oneclick: if multiple moves, be sure we remember capture
1965 cl->piece = board[rf][ff];
1968 cl->rt = wildCard ? cl->rtIn : rt;
1969 cl->ft = wildCard ? cl->ftIn : ft;
1972 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1977 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1979 int illegal = 0; char c = closure->promoCharIn;
1981 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1982 closure->count = closure->captures = 0;
1983 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1984 closure->kind = ImpossibleMove;
1985 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1986 fFilter = closure->ftIn;
1987 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1988 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1989 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1990 closure->count = closure->captures = 0;
1991 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1992 closure->kind = ImpossibleMove;
1993 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1996 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
1997 if (closure->count == 0) {
1998 /* See if it's an illegal move due to check */
2000 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2001 if (closure->count == 0) {
2002 /* No, it's not even that */
2003 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2004 int f, r; // if there is only a single piece of the requested type on the board, use that
2005 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2006 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2007 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2008 if(closure->count > 1) illegal = 0; // ambiguous
2010 if(closure->count == 0) {
2011 if (appData.debugMode) { int i, j;
2012 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2013 for(j=0; j<BOARD_WIDTH; j++)
2014 fprintf(debugFP, "%3d", (int) board[i][j]);
2015 fprintf(debugFP, "\n");
2021 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2022 DisambiguateClosure spare = *closure;
2023 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2024 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2025 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2029 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2030 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2031 if(closure->piece < BlackPawn) { // white
2032 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2033 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2034 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2035 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2036 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2038 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2039 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2040 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2041 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2042 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2045 if(gameInfo.variant == VariantChu) {
2046 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2048 if(gameInfo.variant == VariantShogi) {
2049 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2050 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2051 ChessSquare piece = closure->piece;
2052 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2053 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2054 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2055 c = '+'; // allowed ICS notations
2056 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2057 else if(flags & F_WHITE_ON_MOVE) {
2058 if( (int) piece < (int) WhiteWazir &&
2059 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2060 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2061 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2062 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2063 else /* promotion optional, default is defer */
2064 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2065 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2067 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2068 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2069 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2070 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2071 else /* promotion optional, default is defer */
2072 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2073 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2076 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2077 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2079 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2080 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2081 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2082 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2083 c = PieceToChar(BlackFerz);
2084 else if(gameInfo.variant == VariantGreat)
2085 c = PieceToChar(BlackMan);
2086 else if(gameInfo.variant == VariantGrand)
2087 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2089 c = PieceToChar(BlackQueen);
2090 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2091 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2092 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2093 ChessSquare p = closure->piece;
2094 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2095 closure->kind = ImpossibleMove; // used on non-promotable piece
2096 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2097 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2099 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2100 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2101 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2102 if (closure->count > 1) {
2103 closure->kind = AmbiguousMove;
2106 /* Note: If more than one illegal move matches, but no legal
2107 moves, we return IllegalMove, not AmbiguousMove. Caller
2108 can look at closure->count to detect this.
2110 closure->kind = IllegalMove;
2124 } CoordsToAlgebraicClosure;
2126 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2127 ChessMove kind, int rf, int ff,
2128 int rt, int ft, VOIDSTAR closure));
2131 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2133 register CoordsToAlgebraicClosure *cl =
2134 (CoordsToAlgebraicClosure *) closure;
2136 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2137 (board[rf][ff] == cl->piece
2138 || PieceToChar(board[rf][ff]) == '~' &&
2139 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2143 cl->kind = kind; /* this is the move we want */
2145 cl->file++; /* need file to rule out this move */
2149 cl->rank++; /* need rank to rule out this move */
2151 cl->either++; /* rank or file will rule out this move */
2157 /* Convert coordinates to normal algebraic notation.
2158 promoChar must be NULLCHAR or 'x' if not a promotion.
2161 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2165 char *outp = out, c, capture;
2166 CoordsToAlgebraicClosure cl;
2168 if (rf == DROP_RANK) {
2169 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2170 /* Bughouse piece drop */
2171 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2176 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2178 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2181 if (promoChar == 'x') promoChar = NULLCHAR;
2182 piece = board[rf][ff];
2183 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2188 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2189 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2190 /* Keep short notation if move is illegal only because it
2191 leaves the player in check, but still return IllegalMove */
2192 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2193 if (kind == IllegalMove) break;
2198 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2199 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2200 /* Non-capture; use style "e5" */
2203 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2205 /* Capture; use style "exd5" */
2207 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2211 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2213 /* Use promotion suffix style "=Q" */
2215 if (promoChar != NULLCHAR) {
2216 if(IS_SHOGI(gameInfo.variant)) {
2217 /* [HGM] ... but not in Shogi! */
2218 *outp++ = promoChar == '=' ? '=' : '+';
2221 *outp++ = ToUpper(promoChar);
2230 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2231 /* Code added by Tord: FRC castling. */
2232 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2233 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2235 safeStrCpy(out, "O-O", MOVE_LEN);
2237 safeStrCpy(out, "O-O-O", MOVE_LEN);
2238 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2240 /* End of code added by Tord */
2241 /* Test for castling or ICS wild castling */
2242 /* Use style "O-O" (oh-oh) for PGN compatibility */
2243 else if (rf == rt &&
2244 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2245 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2246 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2247 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2248 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2249 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2251 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2253 /* This notation is always unambiguous, unless there are
2254 kings on both the d and e files, with "wild castling"
2255 possible for the king on the d file and normal castling
2256 possible for the other. ICS rules for wild 9
2257 effectively make castling illegal for either king in
2258 this situation. So I am not going to worry about it;
2259 I'll just generate an ambiguous O-O in this case.
2261 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2264 /* else fall through */
2269 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2270 cl.ft = fFilter = ft;
2272 cl.kind = IllegalMove;
2273 cl.rank = cl.file = cl.either = 0;
2274 c = PieceToChar(piece) ;
2275 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2277 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2278 /* Generate pretty moves for moving into check, but
2279 still return IllegalMove.
2281 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2282 if (cl.kind == IllegalMove) break;
2283 cl.kind = IllegalMove;
2286 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2287 else "Ngf3" or "Ngxf7",
2288 else "N1f3" or "N5xf7",
2289 else "Ng1f3" or "Ng5xf7".
2291 if( c == '~' || c == '+') {
2292 /* [HGM] print nonexistent piece as its demoted version */
2293 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2295 if(c=='+') *outp++ = c;
2296 *outp++ = ToUpper(PieceToChar(piece));
2298 if (cl.file || (cl.either && !cl.rank)) {
2304 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2307 if(board[rt][ft] != EmptySquare)
2313 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2314 if (IS_SHOGI(gameInfo.variant)) {
2315 /* [HGM] in Shogi non-pawns can promote */
2316 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2318 else if (gameInfo.variant == VariantChuChess && promoChar ||
2319 gameInfo.variant != VariantSuper && promoChar &&
2320 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2322 *outp++ = ToUpper(promoChar);
2324 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2326 *outp++ = ToUpper(promoChar);
2332 /* Moving a nonexistent piece */
2336 /* Not a legal move, even ignoring check.
2337 If there was a piece on the from square,
2338 use style "Ng1g3" or "Ng1xe8";
2339 if there was a pawn or nothing (!),
2340 use style "g1g3" or "g1xe8". Use "x"
2341 if a piece was on the to square, even
2342 a piece of the same color.
2346 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2348 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2349 c += (board[r][f] == piece); // count on-board pieces of given type
2350 *outp++ = ToUpper(PieceToChar(piece));
2352 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2356 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2358 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2362 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2363 /* Use promotion suffix style "=Q" */
2364 if (promoChar != NULLCHAR && promoChar != 'x') {
2366 *outp++ = ToUpper(promoChar);
2373 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2382 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2384 int preyStackPointer, chaseStackPointer;
2387 unsigned char rf, ff, rt, ft;
2391 unsigned char rank, file;
2397 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2399 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2400 int rf, int ff, int rt, int ft,
2404 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2405 { // For adding captures that can lead to chase indictment to the chaseStack
2406 if(board[rt][ft] == EmptySquare) return; // non-capture
2407 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2408 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2409 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2410 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2411 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2412 chaseStack[chaseStackPointer].rf = rf;
2413 chaseStack[chaseStackPointer].ff = ff;
2414 chaseStack[chaseStackPointer].rt = rt;
2415 chaseStack[chaseStackPointer].ft = ft;
2416 chaseStackPointer++;
2419 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2420 int rf, int ff, int rt, int ft,
2424 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2425 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2427 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2429 if(board[rt][ft] == EmptySquare) return; // no capture
2430 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2431 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2433 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2434 for(i=0; i<chaseStackPointer; i++) {
2435 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2436 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2437 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2438 chaseStack[i] = chaseStack[--chaseStackPointer];
2444 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2445 int rf, int ff, int rt, int ft,
2449 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2450 { // for determining if a piece (given through the closure) is protected
2451 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2453 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2454 if(appData.debugMode && board[rt][ft] != EmptySquare)
2455 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2458 extern char moveList[MAX_MOVES][MOVE_LEN];
2461 PerpetualChase (int first, int last)
2462 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2465 ChessSquare captured;
2467 preyStackPointer = 0; // clear stack of chased pieces
2468 for(i=first; i<last; i+=2) { // for all positions with same side to move
2469 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2470 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2471 // determine all captures possible after the move, and put them on chaseStack
2472 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2473 if(appData.debugMode) { int n;
2474 for(n=0; n<chaseStackPointer; n++)
2475 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2476 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2477 fprintf(debugFP, ": all capts\n");
2479 // determine all captures possible before the move, and delete them from chaseStack
2480 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2481 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2482 cl.rt = moveList[i][3]-ONE;
2483 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2484 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2485 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2486 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2487 if(appData.debugMode) { int n;
2488 for(n=0; n<chaseStackPointer; n++)
2489 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2490 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2491 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2493 // chaseSack now contains all captures made possible by the move
2494 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2495 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2496 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2498 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2499 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2501 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2502 continue; // C or H attack on R is always chase; leave on chaseStack
2504 if(attacker == victim) {
2505 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2506 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2507 // we can capture back with equal piece, so this is no chase but a sacrifice
2508 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2509 j--; /* ! */ continue;
2514 // the attack is on a lower piece, or on a pinned or blocked equal one
2515 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2516 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2517 // test if the victim is protected by a true protector. First make the capture.
2518 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2519 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2520 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2521 // Then test if the opponent can recapture
2522 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2523 cl.rt = chaseStack[j].rt;
2524 cl.ft = chaseStack[j].ft;
2525 if(appData.debugMode) {
2526 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2528 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2529 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2530 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2531 // unmake the capture
2532 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2533 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2534 // if a recapture was found, piece is protected, and we are not chasing it.
2535 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2536 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2540 // chaseStack now contains all moves that chased
2541 if(appData.debugMode) { int n;
2542 for(n=0; n<chaseStackPointer; n++)
2543 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2544 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2545 fprintf(debugFP, ": chases\n");
2547 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2548 for(j=0; j<chaseStackPointer; j++) {
2549 preyStack[j].rank = chaseStack[j].rt;
2550 preyStack[j].file = chaseStack[j].ft;
2552 preyStackPointer = chaseStackPointer;
2555 for(j=0; j<chaseStackPointer; j++) {
2556 for(k=0; k<preyStackPointer; k++) {
2557 // search the victim of each chase move on the preyStack (first occurrence)
2558 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2559 if(k < tail) break; // piece was already identified as still being chased
2560 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2561 preyStack[tail] = preyStack[k]; // by swapping
2562 preyStack[k] = preyStack[preyStackPointer];
2568 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2569 if(appData.debugMode) { int n;
2570 for(n=0; n<preyStackPointer; n++)
2571 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2572 fprintf(debugFP, "always chased upto ply %d\n", i);
2574 // now adjust the location of the chased pieces according to opponent move
2575 for(j=0; j<preyStackPointer; j++) {
2576 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2577 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2578 preyStack[j].rank = moveList[i+1][3]-ONE;
2579 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2584 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2585 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the