2 * moves.c - Move generation and checking
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.
10 * Enhancements Copyright 2005 Alessandro Scotti
12 * The following terms apply to Digital Equipment Corporation's copyright
14 * ------------------------------------------------------------------------
17 * Permission to use, copy, modify, and distribute this software and its
18 * documentation for any purpose and without fee is hereby granted,
19 * provided that the above copyright notice appear in all copies and that
20 * both that copyright notice and this permission notice appear in
21 * supporting documentation, and that the name of Digital not be
22 * used in advertising or publicity pertaining to distribution of the
23 * software without specific, written prior permission.
25 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
26 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
27 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
28 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
29 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
30 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
32 * ------------------------------------------------------------------------
34 * The following terms apply to the enhanced version of XBoard
35 * distributed by the Free Software Foundation:
36 * ------------------------------------------------------------------------
38 * GNU XBoard is free software: you can redistribute it and/or modify
39 * it under the terms of the GNU General Public License as published by
40 * the Free Software Foundation, either version 3 of the License, or (at
41 * your option) any later version.
43 * GNU XBoard is distributed in the hope that it will be useful, but
44 * WITHOUT ANY WARRANTY; without even the implied warranty of
45 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
46 * General Public License for more details.
48 * You should have received a copy of the GNU General Public License
49 * along with this program. If not, see http://www.gnu.org/licenses/. *
51 *------------------------------------------------------------------------
52 ** See the file ChangeLog for a revision history. */
61 #else /* not HAVE_STRING_H */
63 #endif /* not HAVE_STRING_H */
69 int WhitePiece P((ChessSquare));
70 int BlackPiece P((ChessSquare));
71 int SameColor P((ChessSquare, ChessSquare));
72 int PosFlags(int index);
74 extern signed char initialRights[BOARD_FILES]; /* [HGM] all rights enabled, set in InitPosition */
76 char *pieceDesc[EmptySquare];
77 char *defaultDesc[EmptySquare] = {
78 "fmWfceFifmnD", "N", "B", "R", "Q",
79 "F", "A", "BN", "RN", "W", "K",
80 "mRcpR", "N0", "BW", "RF", "gQ",
81 "", "", "QN", "", "N", "",
83 "", "", "", "", "", "",
85 "", "", "", "", "", "K"
89 WhitePiece (ChessSquare piece)
91 return (int) piece >= (int) WhitePawn && (int) piece < (int) BlackPawn;
95 BlackPiece (ChessSquare piece)
97 return (int) piece >= (int) BlackPawn && (int) piece < (int) EmptySquare;
102 SameColor (ChessSquare piece1, ChessSquare piece2)
104 return ((int) piece1 >= (int) WhitePawn && /* [HGM] can be > King ! */
105 (int) piece1 < (int) BlackPawn &&
106 (int) piece2 >= (int) WhitePawn &&
107 (int) piece2 < (int) BlackPawn)
108 || ((int) piece1 >= (int) BlackPawn &&
109 (int) piece1 < (int) EmptySquare &&
110 (int) piece2 >= (int) BlackPawn &&
111 (int) piece2 < (int) EmptySquare);
114 #define SameColor(piece1, piece2) (piece1 < EmptySquare && piece2 < EmptySquare && (piece1 < BlackPawn) == (piece2 < BlackPawn) || piece1 == DarkSquare || piece2 == DarkSquare)
117 char pieceToChar[] = {
118 'P', 'N', 'B', 'R', 'Q', 'F', 'E', 'A', 'C', 'W', 'M',
119 'O', 'H', 'I', 'J', 'G', 'D', 'V', 'L', 'S', 'U', 'K',
120 'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm',
121 'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k',
123 char pieceNickName[EmptySquare];
126 PieceToChar (ChessSquare p)
128 if((int)p < 0 || (int)p >= (int)EmptySquare) return('x'); /* [HGM] for safety */
129 return pieceToChar[(int) p];
133 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
136 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
138 while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
146 if(c == '.') return EmptySquare;
147 for(i=0; i< (int) EmptySquare; i++)
148 if(pieceNickName[i] == c) return (ChessSquare) i;
149 for(i=0; i< (int) EmptySquare; i++)
150 if(pieceToChar[i] == c) return (ChessSquare) i;
155 CopyBoard (Board to, Board from)
159 for (i = 0; i < BOARD_HEIGHT; i++)
160 for (j = 0; j < BOARD_WIDTH; j++)
161 to[i][j] = from[i][j];
162 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
163 to[VIRGIN][j] = from[VIRGIN][j],
164 to[CASTLING][j] = from[CASTLING][j];
165 to[HOLDINGS_SET] = 0; // flag used in ICS play
169 CompareBoards (Board board1, Board board2)
173 for (i = 0; i < BOARD_HEIGHT; i++)
174 for (j = 0; j < BOARD_WIDTH; j++) {
175 if (board1[i][j] != board2[i][j])
181 char defaultName[] = "PNBRQ......................................K" // white
182 "pnbrq......................................k"; // black
183 char shogiName[] = "PNBRLS...G.++++++..........................K" // white
184 "pnbrls...g.++++++..........................k"; // black
185 char xqName[] = "PH.R.AE..K.C................................" // white
186 "ph.r.ae..k.c................................"; // black
189 CollectPieceDescriptors ()
190 { // make a line of piece descriptions for use in the PGN Piece tag:
191 // dump all engine defined pieces, and pieces with non-standard names,
192 // but suppress black pieces that are the same as their white counterpart
194 static char buf[MSG_SIZ];
195 char *m, c, d, *pieceName = defaultName;
198 if(!pieceDefs) return "";
199 if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
200 if(gameInfo.variant == VariantShogi) pieceName = shogiName;
201 if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
202 for(p=WhitePawn; p<EmptySquare; p++) {
203 if((c = pieceToChar[p]) == '.' || c == '~') continue; // does not participate
204 m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED p] : c);
205 if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == toupper(c)
206 && (c != '+' || pieceToChar[DEMOTED BLACK_TO_WHITE p] == d)) { // black member of normal pair
207 char *wm = pieceDesc[BLACK_TO_WHITE p];
208 if(!m && !wm || m && wm && !strcmp(wm, m)) continue; // moves as a white piece
209 } else // white or unpaired black
210 if((p < BlackPawn || CharToPiece(toupper(d)) != EmptySquare) && // white or lone black
211 !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
212 // TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
213 if(!m) m = defaultDesc[p];
215 snprintf(buf+len, MSG_SIZ-len, "%s%s%c:%s", len ? ";" : "", c == '+' ? "+" : "", d, m);
220 // [HGM] gen: configurable move generation from Betza notation sent by engine.
221 // Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
222 // square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
223 // if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
224 // target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
225 // is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
226 // user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
227 // generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
228 // can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
229 // 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
233 // alphabet "abcdefghijklmnopqrstuvwxyz"
234 char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
235 char xStep[] = "2110.130.102.10.00....0..2";
236 char yStep[] = "2132.133.313.20.11....1..3";
237 char dirType[] = "01000104000200000260050000";
238 char upgrade[] = "AFCD.BGH.JQL.NO.KW....R..Z";
239 char rotate[] = "DRCA.WHG.JKL.NO.QB....F..Z";
241 // alphabet "a b c d e f g h i j k l m n o p q r s t u v w x y z "
242 int dirs1[] = { 0,0x3C,0,0,0,0xC3,0,0, 0,0,0,0xF0,0,0,0,0,0,0x0F,0 ,0,0,0 ,0,0,0,0 };
243 int dirs2[] = { 0,0x18,0,0,0,0x81,0,0xFF,0,0,0,0x60,0,0,0,0,0,0x06,0x66,0,0,0x99,0,0,0,0 };
244 int dirs3[] = { 0,0x38,0,0,0,0x83,0,0xFF,0,0,0,0xE0,0,0,0,0,0,0x0E,0xEE,0,0,0xBB,0,0,0,0 };
245 int dirs4[] = { 0,0x10,0,0,0,0x01,0,0xFF,0,0,0,0x40,0,0,0,0,0,0x04,0x44,0,0,0x11,0,0,0,0 };
247 int rot[][4] = { // rotation matrices for each direction
259 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
265 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
267 char buf[80], *p = desc, *atom = NULL;
268 int mine, his, dir, bit, occup, i;
269 if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
270 while(*p) { // more moves to go
271 int expo = 1, dx, dy, x, y, mode, dirSet, ds2, retry=0, initial=0, jump=1, skip = 0, all = 0;
273 if(*p == 'i') initial = 1, desc = ++p;
274 while(islower(*p)) p++; // skip prefixes
275 if(!isupper(*p)) return; // syntax error: no atom
276 dx = xStep[*p-'A'] - '0';// step vector of atom
277 dy = yStep[*p-'A'] - '0';
278 dirSet = 0; // build direction set based on atom symmetry
279 switch(symmetry[*p-'A']) {
280 case 'B': expo = 0; // bishop, slide
281 case 'F': all = 0xAA; // diagonal atom (degenerate 4-fold)
282 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
283 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
284 int b = dirs1[*desc-'a']; // use wide version
285 if( islower(desc[1]) &&
286 ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim)
287 b = dirs1[*desc-'a'] & dirs1[desc[1]-'a']; // intersect wide & perp wide
292 dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
294 case 'R': expo = 0; // rook, slide
295 case 'W': all = 0x55; // orthogonal atom (non-deg 4-fold)
296 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
297 while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
298 dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
299 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
301 case 'N': all = 0xFF; // oblique atom (degenerate 8-fold)
302 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
303 if(*desc == 'h') { // chiral direction sets 'hr' and 'hl'
304 dirSet = (desc[1] == 'r' ? 0x55 : 0xAA); desc += 2;
306 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
307 int b = dirs2[*desc-'a']; // when alone, use narrow version
308 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
309 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
310 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
311 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
316 if(!dirSet) dirSet = 0xFF;
318 case 'Q': expo = 0; // queen, slide
319 case 'K': all = 0xFF; // non-deg (pseudo) 8-fold
321 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
322 int b = dirs4[*desc-'a']; // when alone, use narrow version
323 if(desc[1] == *desc) desc++; // doubling forces alone
324 else if(islower(desc[1]) && i < '4'
325 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
326 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
331 if(!dirSet) dirSet = (tx < 0 ? 0xFF // default is all directions, but in continuation leg
332 : all == 0xFF ? 0xEF : 0x45); // omits backward, and for 4-fold atoms also diags
333 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
334 ds2 = dirSet & 0xAA; // extract diagonal directions
335 if(dirSet &= 0x55) // start with orthogonal moves, if present
336 retry = 1, dx = 0; // and schedule the diagonal moves for later
337 else dx = dy, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
338 break; // should not have direction indicators
339 default: return; // syntax error: invalid atom
341 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
342 mode = 0; // build mode mask
343 if(*desc == 'm') mode |= 4, desc++; // move to empty
344 if(*desc == 'c') mode |= his, desc++; // capture foe
345 if(*desc == 'd') mode |= mine, desc++; // destroy (capture friend)
346 if(*desc == 'e') mode |= 8, desc++; // e.p. capture last mover
347 if(*desc == 't') mode |= 16, desc++; // exclude enemies as hop platform ('test')
348 if(*desc == 'p') mode |= 32, desc++; // hop over occupied
349 if(*desc == 'g') mode |= 64, desc++; // hop and toggle range
350 if(*desc == 'o') mode |= 128, desc++; // wrap around cylinder board
351 if(*desc == 'y') mode |= 512, desc++; // toggle range on empty square
352 if(*desc == 'n') jump = 0, desc++; // non-jumping
353 while(*desc == 'j') jump++, desc++; // must jump (on B,R,Q: skip first square)
354 if(*desc == 'a') cont = ++desc; // move again after doing what preceded it
355 if(isdigit(*++p)) expo = atoi(p++); // read exponent
356 if(expo > 9) p++; // allow double-digit
357 desc = p; // this is start of next move
358 if(initial && (board[r][f] != initialPosition[r][f] ||
359 r == 0 && board[TOUCHED_W] & 1<<f ||
360 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
361 if(expo > 1 && dx == 0 && dy == 0) { // castling indicated by O + number
362 mode |= 1024; dy = 1;
365 if(!(mode & 15)) mode |= his + 4; // no mode spec, use default = mc
367 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
368 atom = buf; while(islower(*atom)) atom++; // skip to atom
369 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
370 if(mode & 64 + 512) {
371 mode |= 256; // and 'g' too, but converts leaper <-> slider
372 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
373 *atom = upgrade[*atom-'A']; // replace atom, BRQ <-> FWK
374 atom[1] = atom[2] = '\0'; // make sure any old range is stripped off
375 if(expo == 1) atom[1] = '0'; // turn other leapers into riders
377 if(!(mode & 0x30F)) mode |= 4; // and default of this leg = m
379 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
381 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
382 int i = expo, j = skip, hop = mode, vx, vy;
383 if(!(bit & dirSet)) continue; // does not move in this direction
384 if(dy != 1) j = 0; //
385 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
386 vy = dx*rot[dir][2] + dy*rot[dir][3];
387 if(tx < 0) x = f, y = r; // start square
388 else x = tx, y = ty; // from previous to-square if continuation
390 x += vx; y += vy; // step to next square
391 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
392 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT; else break; }
393 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT; else break; }
394 if(j) { j--; continue; } // skip irrespective of occupation
395 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
396 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
397 if(x == f && y == r) occup = 4; else // start square counts as empty
398 if(board[y][x] < BlackPawn) occup = 0x101; else
399 if(board[y][x] < EmptySquare) occup = 0x102; else
401 if(cont) { // non-final leg
402 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
403 if(occup & mode) { // valid intermediate square, do continuation
404 char origAtom = *atom;
405 if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
406 if(occup & mode & 0x104) // no side effects, merge legs to one move
407 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
408 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
410 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
411 if(cnt) { // and if there are
412 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
414 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
418 *atom = origAtom; // undo any interconversion
420 if(occup != 4) break; // occupied squares always terminate the leg
423 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
424 if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
425 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
427 if(mode & 1024) { // castling
428 i = 2; // kludge to elongate move indefinitely
429 if(occup == 4) continue; // skip empty squares
430 if(x == BOARD_LEFT && board[y][x] == initialPosition[y][x]) // reached initial corner piece
431 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
432 if(x == BOARD_RGHT-1 && board[y][x] == initialPosition[y][x])
433 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
436 if(occup & mode) cb(board, flags, NormalMove, r, f, y, x, cl); // allowed, generate
437 if(occup != 4) break; // not valid transit square
440 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
441 } while(retry-- && ds2); // and start doing them
442 if(tx >= 0) break; // don't do other atoms in continuation legs
446 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
449 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
454 if (rt >= BOARD_HEIGHT) break;
455 if (SameColor(board[rf][ff], board[rt][ft])) break;
456 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
457 if (board[rt][ft] != EmptySquare) break;
462 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
468 if (SameColor(board[rf][ff], board[rt][ft])) break;
469 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
470 if (board[rt][ft] != EmptySquare) break;
475 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
477 SlideForward(board, flags, rf, ff, callback, closure);
478 SlideBackward(board, flags, rf, ff, callback, closure);
482 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
484 int i, s, rt = rf, ft;
485 for(s = -1; s <= 1; s+= 2) {
488 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
489 if (SameColor(board[rf][ff], board[rt][ft])) break;
490 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
491 if (board[rt][ft] != EmptySquare) break;
497 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
500 for(s = -1; s <= 1; s+= 2) {
504 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
505 if (SameColor(board[rf][ff], board[rt][ft])) break;
506 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
507 if (board[rt][ft] != EmptySquare) break;
513 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
516 for(s = -1; s <= 1; s+= 2) {
520 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
521 if (SameColor(board[rf][ff], board[rt][ft])) break;
522 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
523 if (board[rt][ft] != EmptySquare) break;
529 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
531 SlideVertical(board, flags, rf, ff, callback, closure);
532 SlideSideways(board, flags, rf, ff, callback, closure);
536 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
538 SlideDiagForward(board, flags, rf, ff, callback, closure);
539 SlideDiagBackward(board, flags, rf, ff, callback, closure);
543 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
544 { // Lion-like move of Horned Falcon and Souring Eagle
545 int ft = ff + dx, rt = rf + dy;
546 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
548 if (!SameColor(board[rf][ff], board[rt][ft]))
549 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
552 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
554 if (!SameColor(board[rf][ff], board[rt][ft]))
555 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
556 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
557 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
562 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
564 int ft = ff, rt = rf + 1;
565 if (rt >= BOARD_HEIGHT) return;
566 if (SameColor(board[rf][ff], board[rt][ft])) return;
567 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
571 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
573 int ft = ff, rt = rf - 1;
575 if (SameColor(board[rf][ff], board[rt][ft])) return;
576 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
580 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
584 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
585 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
587 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
588 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
592 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
595 if (rt >= BOARD_HEIGHT) return;
597 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
598 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
600 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
601 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
605 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
610 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
611 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
613 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
614 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
618 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
620 StepForward(board, flags, rf, ff, callback, closure);
621 StepBackward(board, flags, rf, ff, callback, closure);
625 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
627 StepDiagForward(board, flags, rf, ff, callback, closure);
628 StepDiagBackward(board, flags, rf, ff, callback, closure);
632 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
634 StepVertical(board, flags, rf, ff, callback, closure);
635 StepSideways(board, flags, rf, ff, callback, closure);
639 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
642 for (i = -1; i <= 1; i += 2)
643 for (j = -1; j <= 1; j += 2)
644 for (s = 1; s <= 2; s++) {
647 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
648 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
649 && !SameColor(board[rf][ff], board[rt][ft]))
650 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
654 /* Call callback once for each pseudo-legal move in the given
655 position, except castling moves. A move is pseudo-legal if it is
656 legal, or if it would be legal except that it leaves the king in
657 check. In the arguments, epfile is EP_NONE if the previous move
658 was not a double pawn push, or the file 0..7 if it was, or
659 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
660 Promotion moves generated are to Queen only.
663 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
664 // speed: only do moves with this piece type
667 int i, j, d, s, fs, rs, rt, ft, m;
668 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
669 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
671 for (rf = 0; rf < BOARD_HEIGHT; rf++)
672 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
675 if(board[rf][ff] == EmptySquare) continue;
676 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
677 m = 0; piece = board[rf][ff];
678 if(PieceToChar(piece) == '~')
679 piece = (ChessSquare) ( DEMOTED piece );
680 if(filter != EmptySquare && piece != filter) continue;
681 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
682 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
685 if(IS_SHOGI(gameInfo.variant))
686 piece = (ChessSquare) ( SHOGI piece );
688 switch ((int)piece) {
689 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
691 /* can't happen ([HGM] except for faries...) */
695 if(gameInfo.variant == VariantXiangqi) {
696 /* [HGM] capture and move straight ahead in Xiangqi */
697 if (rf < BOARD_HEIGHT-1 &&
698 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
699 callback(board, flags, NormalMove,
700 rf, ff, rf + 1, ff, closure);
702 /* and move sideways when across the river */
703 for (s = -1; s <= 1; s += 2) {
704 if (rf >= BOARD_HEIGHT>>1 &&
705 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
706 !WhitePiece(board[rf][ff+s]) ) {
707 callback(board, flags, NormalMove,
708 rf, ff, rf, ff+s, closure);
713 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
714 callback(board, flags,
715 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
716 rf, ff, rf + 1, ff, closure);
718 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
719 gameInfo.variant != VariantShatranj && /* [HGM] */
720 gameInfo.variant != VariantCourier && /* [HGM] */
721 board[rf+2][ff] == EmptySquare ) {
722 callback(board, flags, NormalMove,
723 rf, ff, rf+2, ff, closure);
725 for (s = -1; s <= 1; s += 2) {
726 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
727 ((flags & F_KRIEGSPIEL_CAPTURE) ||
728 BlackPiece(board[rf + 1][ff + s]))) {
729 callback(board, flags,
730 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
731 rf, ff, rf + 1, ff + s, closure);
733 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
734 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
735 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
736 board[rf][ff + s] == BlackPawn &&
737 board[rf+1][ff + s] == EmptySquare) {
738 callback(board, flags, WhiteCapturesEnPassant,
739 rf, ff, rf+1, ff + s, closure);
746 if(gameInfo.variant == VariantXiangqi) {
747 /* [HGM] capture straight ahead in Xiangqi */
748 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
749 callback(board, flags, NormalMove,
750 rf, ff, rf - 1, ff, closure);
752 /* and move sideways when across the river */
753 for (s = -1; s <= 1; s += 2) {
754 if (rf < BOARD_HEIGHT>>1 &&
755 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
756 !BlackPiece(board[rf][ff+s]) ) {
757 callback(board, flags, NormalMove,
758 rf, ff, rf, ff+s, closure);
763 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
764 callback(board, flags,
765 rf <= promoRank ? BlackPromotion : NormalMove,
766 rf, ff, rf - 1, ff, closure);
768 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
769 gameInfo.variant != VariantShatranj && /* [HGM] */
770 gameInfo.variant != VariantCourier && /* [HGM] */
771 board[rf-2][ff] == EmptySquare) {
772 callback(board, flags, NormalMove,
773 rf, ff, rf-2, ff, closure);
775 for (s = -1; s <= 1; s += 2) {
776 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
777 ((flags & F_KRIEGSPIEL_CAPTURE) ||
778 WhitePiece(board[rf - 1][ff + s]))) {
779 callback(board, flags,
780 rf <= promoRank ? BlackPromotion : NormalMove,
781 rf, ff, rf - 1, ff + s, closure);
783 if (rf < BOARD_HEIGHT>>1) {
784 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
785 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
786 board[rf][ff + s] == WhitePawn &&
787 board[rf-1][ff + s] == EmptySquare) {
788 callback(board, flags, BlackCapturesEnPassant,
789 rf, ff, rf-1, ff + s, closure);
799 for (i = -1; i <= 1; i += 2)
800 for (j = -1; j <= 1; j += 2)
801 for (s = 1; s <= 2; s++) {
804 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
805 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
806 && !SameColor(board[rf][ff], board[rt][ft]))
807 callback(board, flags, NormalMove,
808 rf, ff, rt, ft, closure);
812 case SHOGI WhiteKnight:
813 for (s = -1; s <= 1; s += 2) {
814 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
815 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
816 callback(board, flags, NormalMove,
817 rf, ff, rf + 2, ff + s, closure);
822 case SHOGI BlackKnight:
823 for (s = -1; s <= 1; s += 2) {
824 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
825 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
826 callback(board, flags, NormalMove,
827 rf, ff, rf - 2, ff + s, closure);
834 for (d = 0; d <= 1; d++)
835 for (s = -1; s <= 1; s += 2) {
838 rt = rf + (i * s) * d;
839 ft = ff + (i * s) * (1 - d);
840 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
841 if (m == 0 && board[rt][ft] == EmptySquare)
842 callback(board, flags, NormalMove,
843 rf, ff, rt, ft, closure);
844 if (m == 1 && board[rt][ft] != EmptySquare &&
845 !SameColor(board[rf][ff], board[rt][ft]) )
846 callback(board, flags, NormalMove,
847 rf, ff, rt, ft, closure);
848 if (board[rt][ft] != EmptySquare && m++) break;
853 /* Gold General (and all its promoted versions) . First do the */
854 /* diagonal forward steps, then proceed as normal Wazir */
855 case SHOGI (PROMOTED WhitePawn):
856 if(gameInfo.variant == VariantShogi) goto WhiteGold;
857 case SHOGI (PROMOTED BlackPawn):
858 if(gameInfo.variant == VariantShogi) goto BlackGold;
859 SlideVertical(board, flags, rf, ff, callback, closure);
862 case SHOGI (PROMOTED WhiteKnight):
863 if(gameInfo.variant == VariantShogi) goto WhiteGold;
864 case SHOGI BlackDrunk:
865 case SHOGI BlackAlfil:
866 Ferz(board, flags, rf, ff, callback, closure);
867 StepSideways(board, flags, rf, ff, callback, closure);
868 StepBackward(board, flags, rf, ff, callback, closure);
871 case SHOGI (PROMOTED BlackKnight):
872 if(gameInfo.variant == VariantShogi) goto BlackGold;
873 case SHOGI WhiteDrunk:
874 case SHOGI WhiteAlfil:
875 Ferz(board, flags, rf, ff, callback, closure);
876 StepSideways(board, flags, rf, ff, callback, closure);
877 StepForward(board, flags, rf, ff, callback, closure);
881 case SHOGI WhiteStag:
882 case SHOGI BlackStag:
883 if(gameInfo.variant == VariantShogi) goto BlackGold;
884 SlideVertical(board, flags, rf, ff, callback, closure);
885 Ferz(board, flags, rf, ff, callback, closure);
886 StepSideways(board, flags, rf, ff, callback, closure);
889 case SHOGI (PROMOTED WhiteQueen):
890 case SHOGI WhiteTokin:
891 case SHOGI WhiteWazir:
893 StepDiagForward(board, flags, rf, ff, callback, closure);
894 Wazir(board, flags, rf, ff, callback, closure);
897 case SHOGI (PROMOTED BlackQueen):
898 case SHOGI BlackTokin:
899 case SHOGI BlackWazir:
901 StepDiagBackward(board, flags, rf, ff, callback, closure);
902 Wazir(board, flags, rf, ff, callback, closure);
907 Wazir(board, flags, rf, ff, callback, closure);
910 case SHOGI WhiteMarshall:
911 case SHOGI BlackMarshall:
912 Ferz(board, flags, rf, ff, callback, closure);
913 for (d = 0; d <= 1; d++)
914 for (s = -2; s <= 2; s += 4) {
916 ft = ff + s * (1 - d);
917 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
918 if (!SameColor(board[rf][ff], board[rt][ft]) )
919 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
923 case SHOGI WhiteAngel:
924 case SHOGI BlackAngel:
925 Wazir(board, flags, rf, ff, callback, closure);
929 /* [HGM] support Shatranj pieces */
930 for (rs = -1; rs <= 1; rs += 2)
931 for (fs = -1; fs <= 1; fs += 2) {
934 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
935 && ( gameInfo.variant != VariantXiangqi ||
936 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
938 && !SameColor(board[rf][ff], board[rt][ft]))
939 callback(board, flags, NormalMove,
940 rf, ff, rt, ft, closure);
941 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
942 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
943 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
945 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
946 && !SameColor(board[rf][ff], board[rt][ft]))
947 callback(board, flags, NormalMove,
948 rf, ff, rt, ft, closure);
950 if(gameInfo.variant == VariantSpartan)
951 for(fs = -1; fs <= 1; fs += 2) {
953 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
954 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
958 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
961 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
962 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
963 for (s = -2; s <= 2; s += 4) {
965 ft = ff + s * (1 - d);
966 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
967 if (SameColor(board[rf][ff], board[rt][ft])) continue;
968 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
971 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
972 case SHOGI WhiteCardinal:
973 case SHOGI BlackCardinal:
974 case SHOGI WhitePCardinal:
975 case SHOGI BlackPCardinal:
977 Bishop(board, flags, rf, ff, callback, closure);
978 Wazir(board, flags, rf, ff, callback, closure);
981 /* Capablanca Archbishop continues as Knight */
984 Knight(board, flags, rf, ff, callback, closure);
986 /* Shogi Bishops are ordinary Bishops */
987 case SHOGI WhiteBishop:
988 case SHOGI BlackBishop:
989 case SHOGI WhitePBishop:
990 case SHOGI BlackPBishop:
993 Bishop(board, flags, rf, ff, callback, closure);
996 /* Shogi Lance is unlike anything, and asymmetric at that */
997 case SHOGI WhiteQueen:
998 if(gameInfo.variant == VariantChu) goto doQueen;
1002 if (rt >= BOARD_HEIGHT) break;
1003 if (SameColor(board[rf][ff], board[rt][ft])) break;
1004 callback(board, flags, NormalMove,
1005 rf, ff, rt, ft, closure);
1006 if (board[rt][ft] != EmptySquare) break;
1010 case SHOGI BlackQueen:
1011 if(gameInfo.variant == VariantChu) goto doQueen;
1016 if (SameColor(board[rf][ff], board[rt][ft])) break;
1017 callback(board, flags, NormalMove,
1018 rf, ff, rt, ft, closure);
1019 if (board[rt][ft] != EmptySquare) break;
1023 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1026 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1027 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1028 for (s = -2; s <= 2; s += 4) {
1030 ft = ff + s * (1 - d);
1031 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1032 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1033 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1034 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1036 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1037 Wazir(board, flags, rf, ff, callback, closure);
1039 Rook(board, flags, rf, ff, callback, closure);
1042 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1043 case SHOGI WhiteDragon:
1044 case SHOGI BlackDragon:
1045 case SHOGI WhitePDragon:
1046 case SHOGI BlackPDragon:
1048 Rook(board, flags, rf, ff, callback, closure);
1049 Ferz(board, flags, rf, ff, callback, closure);
1053 /* Capablanca Chancellor sets flag to continue as Knight */
1056 Rook(board, flags, rf, ff, callback, closure);
1057 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1058 Ferz(board, flags, rf, ff, callback, closure);
1060 Knight(board, flags, rf, ff, callback, closure);
1063 /* Shogi Rooks are ordinary Rooks */
1064 case SHOGI WhiteRook:
1065 case SHOGI BlackRook:
1066 case SHOGI WhitePRook:
1067 case SHOGI BlackPRook:
1070 Rook(board, flags, rf, ff, callback, closure);
1075 case SHOGI WhiteMother:
1076 case SHOGI BlackMother:
1078 Rook(board, flags, rf, ff, callback, closure);
1079 Bishop(board, flags, rf, ff, callback, closure);
1082 case SHOGI WhitePawn:
1083 StepForward(board, flags, rf, ff, callback, closure);
1086 case SHOGI BlackPawn:
1087 StepBackward(board, flags, rf, ff, callback, closure);
1091 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1092 case SHOGI WhiteFerz:
1093 Ferz(board, flags, rf, ff, callback, closure);
1094 StepForward(board, flags, rf, ff, callback, closure);
1098 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1099 case SHOGI BlackFerz:
1100 StepBackward(board, flags, rf, ff, callback, closure);
1104 /* [HGM] support Shatranj pieces */
1105 Ferz(board, flags, rf, ff, callback, closure);
1110 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1113 case SHOGI WhiteMonarch:
1114 case SHOGI BlackMonarch:
1115 case SHOGI WhiteKing:
1116 case SHOGI BlackKing:
1119 Ferz(board, flags, rf, ff, callback, closure);
1120 Wazir(board, flags, rf, ff, callback, closure);
1123 case WhiteNightrider:
1124 case BlackNightrider:
1125 for (i = -1; i <= 1; i += 2)
1126 for (j = -1; j <= 1; j += 2)
1127 for (s = 1; s <= 2; s++) { int k;
1130 ft = ff + k*j*(3-s);
1131 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1132 if (SameColor(board[rf][ff], board[rt][ft])) break;
1133 callback(board, flags, NormalMove,
1134 rf, ff, rt, ft, closure);
1135 if (board[rt][ft] != EmptySquare) break;
1141 Bishop(board, flags, rf, ff, callback, closure);
1142 Rook(board, flags, rf, ff, callback, closure);
1143 Knight(board, flags, rf, ff, callback, closure);
1146 // Use Lance as Berolina / Spartan Pawn.
1148 if(gameInfo.variant == VariantSuper) goto Amazon;
1149 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1150 callback(board, flags,
1151 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1152 rf, ff, rf + 1, ff, closure);
1153 for (s = -1; s <= 1; s += 2) {
1154 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1155 callback(board, flags,
1156 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1157 rf, ff, rf + 1, ff + s, closure);
1158 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1159 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1164 if(gameInfo.variant == VariantSuper) goto Amazon;
1165 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1166 callback(board, flags,
1167 rf <= promoRank ? BlackPromotion : NormalMove,
1168 rf, ff, rf - 1, ff, closure);
1169 for (s = -1; s <= 1; s += 2) {
1170 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1171 callback(board, flags,
1172 rf <= promoRank ? BlackPromotion : NormalMove,
1173 rf, ff, rf - 1, ff + s, closure);
1174 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1175 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1179 case SHOGI WhiteNothing:
1180 case SHOGI BlackNothing:
1181 case SHOGI WhiteLion:
1182 case SHOGI BlackLion:
1185 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1186 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1187 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1188 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1189 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1190 rf, ff, rt, ft, closure);
1195 case SHOGI WhiteFalcon:
1196 case SHOGI BlackFalcon:
1197 case SHOGI WhitePDagger:
1198 case SHOGI BlackPDagger:
1199 SlideSideways(board, flags, rf, ff, callback, closure);
1200 StepVertical(board, flags, rf, ff, callback, closure);
1203 case SHOGI WhiteCobra:
1204 case SHOGI BlackCobra:
1205 StepVertical(board, flags, rf, ff, callback, closure);
1208 case SHOGI (PROMOTED WhiteFerz):
1209 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1210 case SHOGI (PROMOTED BlackFerz):
1211 if(gameInfo.variant == VariantShogi) goto BlackGold;
1212 case SHOGI WhitePSword:
1213 case SHOGI BlackPSword:
1214 SlideVertical(board, flags, rf, ff, callback, closure);
1215 StepSideways(board, flags, rf, ff, callback, closure);
1218 case SHOGI WhiteUnicorn:
1219 case SHOGI BlackUnicorn:
1220 Ferz(board, flags, rf, ff, callback, closure);
1221 StepVertical(board, flags, rf, ff, callback, closure);
1224 case SHOGI WhiteMan:
1225 StepDiagForward(board, flags, rf, ff, callback, closure);
1226 StepVertical(board, flags, rf, ff, callback, closure);
1229 case SHOGI BlackMan:
1230 StepDiagBackward(board, flags, rf, ff, callback, closure);
1231 StepVertical(board, flags, rf, ff, callback, closure);
1234 case SHOGI WhiteHCrown:
1235 case SHOGI BlackHCrown:
1236 Bishop(board, flags, rf, ff, callback, closure);
1237 SlideSideways(board, flags, rf, ff, callback, closure);
1240 case SHOGI WhiteCrown:
1241 case SHOGI BlackCrown:
1242 Bishop(board, flags, rf, ff, callback, closure);
1243 SlideVertical(board, flags, rf, ff, callback, closure);
1246 case SHOGI WhiteHorned:
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 SlideBackward(board, flags, rf, ff, callback, closure);
1255 case SHOGI BlackHorned:
1256 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1257 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1258 if(killX >= 0) break;
1259 Bishop(board, flags, rf, ff, callback, closure);
1260 SlideSideways(board, flags, rf, ff, callback, closure);
1261 SlideForward(board, flags, rf, ff, callback, closure);
1264 case SHOGI WhiteEagle:
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 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1273 case SHOGI BlackEagle:
1274 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1275 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1276 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1277 if(killX >= 0) break;
1278 Rook(board, flags, rf, ff, callback, closure);
1279 SlideDiagForward(board, flags, rf, ff, callback, closure);
1282 case SHOGI WhiteDolphin:
1283 case SHOGI BlackHorse:
1284 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1285 SlideVertical(board, flags, rf, ff, callback, closure);
1288 case SHOGI BlackDolphin:
1289 case SHOGI WhiteHorse:
1290 SlideDiagForward(board, flags, rf, ff, callback, closure);
1291 SlideVertical(board, flags, rf, ff, callback, closure);
1294 case SHOGI WhiteLance:
1295 SlideForward(board, flags, rf, ff, callback, closure);
1298 case SHOGI BlackLance:
1299 SlideBackward(board, flags, rf, ff, callback, closure);
1302 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1306 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1319 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1320 Board xqCheckers, nullBoard;
1322 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1323 int rf, int ff, int rt, int ft,
1327 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1329 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1331 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1333 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1335 if (!(flags & F_IGNORE_CHECK) ) {
1336 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1339 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1340 kings += (board[r][f] == BlackKing);
1344 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1346 check = CheckTest(board, flags, rf, ff, rt, ft,
1347 kind == WhiteCapturesEnPassant ||
1348 kind == BlackCapturesEnPassant);
1349 if(promo) board[rf][ff] = BlackLance;
1352 if (flags & F_ATOMIC_CAPTURE) {
1353 if (board[rt][ft] != EmptySquare ||
1354 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1356 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1357 if (board[rf][ff] == king) return;
1358 for (r = rt-1; r <= rt+1; r++) {
1359 for (f = ft-1; f <= ft+1; f++) {
1360 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1361 board[r][f] == king) return;
1366 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1373 int captures; // [HGM] losers
1374 } LegalityTestClosure;
1377 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1378 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1379 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1380 moves that would destroy your own king. The CASTLE_OK flags are
1381 true if castling is not yet ruled out by a move of the king or
1382 rook. Return TRUE if the player on move is currently in check and
1383 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1385 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1388 int ff, ft, k, left, right, swap;
1389 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1390 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1391 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1396 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1397 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1398 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1400 if (inCheck) return TRUE;
1402 /* Generate castling moves */
1403 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1404 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1407 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1408 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1410 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1411 if ((flags & F_WHITE_ON_MOVE) &&
1412 (flags & F_WHITE_KCASTLE_OK) &&
1413 board[0][ff] == wKing &&
1414 board[0][ff + 1] == EmptySquare &&
1415 board[0][ff + 2] == EmptySquare &&
1416 board[0][BOARD_RGHT-3] == EmptySquare &&
1417 board[0][BOARD_RGHT-2] == EmptySquare &&
1418 board[0][BOARD_RGHT-1] == WhiteRook &&
1419 castlingRights[0] != NoRights && /* [HGM] check rights */
1420 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1422 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1423 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1424 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1425 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1427 callback(board, flags,
1428 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1429 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1431 if ((flags & F_WHITE_ON_MOVE) &&
1432 (flags & F_WHITE_QCASTLE_OK) &&
1433 board[0][ff] == wKing &&
1434 board[0][ff - 1] == EmptySquare &&
1435 board[0][ff - 2] == EmptySquare &&
1436 board[0][BOARD_LEFT+2] == EmptySquare &&
1437 board[0][BOARD_LEFT+1] == EmptySquare &&
1438 board[0][BOARD_LEFT+0] == WhiteRook &&
1439 castlingRights[1] != NoRights && /* [HGM] check rights */
1440 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1442 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1443 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1444 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1446 callback(board, flags,
1447 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1448 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1450 if (!(flags & F_WHITE_ON_MOVE) &&
1451 (flags & F_BLACK_KCASTLE_OK) &&
1452 board[BOARD_HEIGHT-1][ff] == bKing &&
1453 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1454 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1455 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1456 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1457 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1458 castlingRights[3] != NoRights && /* [HGM] check rights */
1459 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1461 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1462 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1463 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1464 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1466 callback(board, flags,
1467 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1468 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1470 if (!(flags & F_WHITE_ON_MOVE) &&
1471 (flags & F_BLACK_QCASTLE_OK) &&
1472 board[BOARD_HEIGHT-1][ff] == bKing &&
1473 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1474 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1475 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1476 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1477 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1478 castlingRights[4] != NoRights && /* [HGM] check rights */
1479 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1481 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1482 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1483 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1485 callback(board, flags,
1486 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1487 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1491 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1493 /* generate all potential FRC castling moves (KxR), ignoring flags */
1494 /* [HGM] test if the Rooks we find have castling rights */
1495 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1498 if ((flags & F_WHITE_ON_MOVE) != 0) {
1499 ff = castlingRights[2]; /* King file if we have any rights */
1500 if(ff != NoRights && board[0][ff] == WhiteKing) {
1501 if (appData.debugMode) {
1502 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1503 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1505 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1507 right = BOARD_RGHT-2;
1508 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1509 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1510 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1511 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1512 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1513 if(ft != NoRights && board[0][ft] == WhiteRook) {
1514 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1515 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1518 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1519 left = BOARD_LEFT+2;
1521 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1522 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1523 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1524 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1525 if(ff > BOARD_LEFT+2)
1526 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1527 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1528 if(ft != NoRights && board[0][ft] == WhiteRook) {
1529 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1530 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1534 ff = castlingRights[5]; /* King file if we have any rights */
1535 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1536 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1538 right = BOARD_RGHT-2;
1539 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1540 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1541 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1542 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1543 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1544 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1545 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1546 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1549 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1550 left = BOARD_LEFT+2;
1552 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1553 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1554 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1555 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1556 if(ff > BOARD_LEFT+2)
1557 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1558 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1559 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1560 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1561 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1578 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1579 int rf, int ff, int rt, int ft,
1584 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1586 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1588 if (rt == cl->rking && ft == cl->fking) {
1589 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1591 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1593 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1594 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1595 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1599 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1600 he leave himself in check? Or if rf == -1, is the player on move
1601 in check now? enPassant must be TRUE if the indicated move is an
1602 e.p. capture. The possibility of castling out of a check along the
1603 back rank is not accounted for (i.e., we still return nonzero), as
1604 this is illegal anyway. Return value is the number of times the
1605 king is in check. */
1607 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1609 CheckTestClosure cl;
1610 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1611 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1612 /* Suppress warnings on uninitialized variables */
1614 if(gameInfo.variant == VariantXiangqi)
1615 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1616 if(gameInfo.variant == VariantKnightmate)
1617 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1618 if(gameInfo.variant == VariantChu) { // strictly speaking this is not needed, as Chu officially has no check
1619 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1620 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1621 if(board[r][f] == k || board[r][f] == prince) {
1622 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1623 king = board[r][f]; // remember hich one we had
1630 captured = board[rf][ft];
1631 board[rf][ft] = EmptySquare;
1633 captured = board[rt][ft];
1634 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; }
1636 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1637 board[rt][ft] = board[rf][ff];
1638 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1640 ep = board[EP_STATUS];
1641 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1642 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1643 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1644 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1645 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1646 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1650 /* For compatibility with ICS wild 9, we scan the board in the
1651 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1652 and we test only whether that one is in check. */
1653 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1654 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1655 if (board[cl.rking][cl.fking] == king) {
1657 if(gameInfo.variant == VariantXiangqi) {
1658 /* [HGM] In Xiangqi opposing Kings means check as well */
1660 dir = (king >= BlackPawn) ? -1 : 1;
1661 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1662 board[i][cl.fking] == EmptySquare; i+=dir );
1663 if(i>=0 && i<BOARD_HEIGHT &&
1664 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1667 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1668 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1669 goto undo_move; /* 2-level break */
1676 if(rf != DROP_RANK) // [HGM] drop
1677 board[rf][ff] = board[rt][ft];
1679 board[rf][ft] = captured;
1680 board[rt][ft] = EmptySquare;
1682 if(killX >= 0) board[killY][killX] = trampled;
1683 board[rt][ft] = captured;
1685 board[EP_STATUS] = ep;
1688 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1692 HasLion (Board board, int flags)
1694 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1696 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1697 if(board[r][f] == lion) return 1;
1702 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1703 { // [HGM] put drop legality testing in separate routine for clarity
1705 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1706 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1707 n = PieceToNumber(piece);
1708 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1709 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1710 return ImpossibleMove; // piece not available
1711 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1712 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1713 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1714 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1715 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1716 if(piece == WhitePawn || piece == BlackPawn) {
1717 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1718 for(r=1; r<BOARD_HEIGHT-1; r++)
1719 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1720 // should still test if we mate with this Pawn
1722 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1723 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1725 if( (piece == WhitePawn || piece == BlackPawn) &&
1726 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1727 return IllegalMove; /* no pawn drops on 1st/8th */
1729 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1730 if (!(flags & F_IGNORE_CHECK) &&
1731 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1732 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1735 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1736 int rf, int ff, int rt, int ft,
1740 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1742 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1744 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1745 cl->captures++; // [HGM] losers: count legal captures
1746 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1751 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1753 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1755 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1756 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1757 piece = filterPiece = board[rf][ff];
1758 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1760 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1761 /* (perhaps we should disallow moves that obviously leave us in check?) */
1762 if((piece == WhiteFalcon || piece == BlackFalcon ||
1763 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1764 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1768 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1769 cl.ft = fFilter = ft;
1770 cl.kind = IllegalMove;
1771 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1772 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1773 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1774 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1775 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1776 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1778 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1779 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1780 if(board[rf][ff] < BlackPawn) { // white
1781 if(rf != 0) return IllegalMove; // must be on back rank
1782 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1783 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1784 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1785 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1787 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1788 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1789 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1790 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1791 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1794 if(gameInfo.variant == VariantChu) {
1795 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1796 if(promoChar != '+')
1797 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1798 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1799 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1801 if(gameInfo.variant == VariantShogi) {
1802 /* [HGM] Shogi promotions. '=' means defer */
1803 if(rf != DROP_RANK && cl.kind == NormalMove) {
1804 ChessSquare piece = board[rf][ff];
1806 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1807 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1808 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1809 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1810 promoChar = '+'; // allowed ICS notations
1811 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1812 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1813 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1814 else if(flags & F_WHITE_ON_MOVE) {
1815 if( (int) piece < (int) WhiteWazir &&
1816 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1817 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1818 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1819 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1820 else /* promotion optional, default is defer */
1821 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1822 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1824 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1825 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1826 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1827 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1828 else /* promotion optional, default is defer */
1829 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1830 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1834 if (promoChar != NULLCHAR) {
1835 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1836 ChessSquare piece = board[rf][ff];
1837 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1838 // should test if in zone, really
1839 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1841 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1843 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1844 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1845 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1846 if(piece == EmptySquare)
1847 cl.kind = ImpossibleMove; // non-existing piece
1848 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1849 cl.kind = IllegalMove; // no two Lions
1850 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1851 if(promoChar != PieceToChar(BlackKing)) {
1852 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1853 if(piece == BlackLance) cl.kind = ImpossibleMove;
1854 } else { // promotion to King allowed only if we do not have two yet
1855 int r, f, kings = 0;
1856 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1857 if(kings == 2) cl.kind = IllegalMove;
1859 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1860 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1861 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1862 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1863 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1864 cl.kind = IllegalMove; // promotion to King usually not allowed
1866 cl.kind = IllegalMove;
1876 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1877 int rf, int ff, int rt, int ft,
1881 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1883 register MateTestClosure *cl = (MateTestClosure *) closure;
1888 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1890 MateTest (Board board, int flags)
1893 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1894 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1896 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1897 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1898 nrKing += (board[r][f] == king); // stm has king
1899 if( board[r][f] != EmptySquare ) {
1900 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1905 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1906 case VariantShatranj:
1907 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1911 if(nrKing == 0) return MT_NOKING;
1914 if(myPieces == 1) return MT_BARE;
1917 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1918 // [HGM] 3check: yet to do!
1920 return inCheck ? MT_CHECK : MT_NONE;
1922 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1923 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1924 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1925 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1926 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1927 if(board[n][holdings] != EmptySquare) {
1928 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1929 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1932 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1933 return myPieces == hisPieces ? MT_STALEMATE :
1934 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1935 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1936 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1938 return inCheck ? MT_CHECKMATE
1939 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1940 MT_STAINMATE : MT_STALEMATE;
1945 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1946 int rf, int ff, int rt, int ft,
1950 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1952 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1953 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1955 // [HGM] wild: for wild-card pieces rt and rf are dummies
1956 if(piece == WhiteFalcon || piece == BlackFalcon ||
1957 piece == WhiteCobra || piece == BlackCobra)
1960 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1961 || PieceToChar(board[rf][ff]) == '~'
1962 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1964 (cl->rfIn == -1 || cl->rfIn == rf) &&
1965 (cl->ffIn == -1 || cl->ffIn == ff) &&
1966 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1967 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1969 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1972 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1973 // [HGM] oneclick: if multiple moves, be sure we remember capture
1974 cl->piece = board[rf][ff];
1977 cl->rt = wildCard ? cl->rtIn : rt;
1978 cl->ft = wildCard ? cl->ftIn : ft;
1981 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1986 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1988 int illegal = 0; char c = closure->promoCharIn;
1990 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1991 closure->count = closure->captures = 0;
1992 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1993 closure->kind = ImpossibleMove;
1994 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1995 fFilter = closure->ftIn;
1996 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1997 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1998 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1999 closure->count = closure->captures = 0;
2000 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2001 closure->kind = ImpossibleMove;
2002 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2005 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2006 if (closure->count == 0) {
2007 /* See if it's an illegal move due to check */
2009 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2010 if (closure->count == 0) {
2011 /* No, it's not even that */
2012 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2013 int f, r; // if there is only a single piece of the requested type on the board, use that
2014 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2015 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2016 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2017 if(closure->count > 1) illegal = 0; // ambiguous
2019 if(closure->count == 0) {
2020 if (appData.debugMode) { int i, j;
2021 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2022 for(j=0; j<BOARD_WIDTH; j++)
2023 fprintf(debugFP, "%3d", (int) board[i][j]);
2024 fprintf(debugFP, "\n");
2030 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2031 DisambiguateClosure spare = *closure;
2032 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2033 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2034 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2038 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2039 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2040 if(closure->piece < BlackPawn) { // white
2041 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2042 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2043 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2044 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2045 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2047 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2048 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2049 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2050 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2051 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2054 if(gameInfo.variant == VariantChu) {
2055 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2057 if(gameInfo.variant == VariantShogi) {
2058 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2059 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2060 ChessSquare piece = closure->piece;
2061 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2062 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2063 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2064 c = '+'; // allowed ICS notations
2065 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2066 else if(flags & F_WHITE_ON_MOVE) {
2067 if( (int) piece < (int) WhiteWazir &&
2068 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2069 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2070 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2071 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2072 else /* promotion optional, default is defer */
2073 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2074 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2076 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2077 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2078 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2079 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2080 else /* promotion optional, default is defer */
2081 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2082 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2085 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2086 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2088 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2089 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2090 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2091 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2092 c = PieceToChar(BlackFerz);
2093 else if(gameInfo.variant == VariantGreat)
2094 c = PieceToChar(BlackMan);
2095 else if(gameInfo.variant == VariantGrand)
2096 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2098 c = PieceToChar(BlackQueen);
2099 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2100 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2101 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2102 ChessSquare p = closure->piece;
2103 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2104 closure->kind = ImpossibleMove; // used on non-promotable piece
2105 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2106 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2108 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2109 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2110 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2111 if (closure->count > 1) {
2112 closure->kind = AmbiguousMove;
2115 /* Note: If more than one illegal move matches, but no legal
2116 moves, we return IllegalMove, not AmbiguousMove. Caller
2117 can look at closure->count to detect this.
2119 closure->kind = IllegalMove;
2133 } CoordsToAlgebraicClosure;
2135 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2136 ChessMove kind, int rf, int ff,
2137 int rt, int ft, VOIDSTAR closure));
2140 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2142 register CoordsToAlgebraicClosure *cl =
2143 (CoordsToAlgebraicClosure *) closure;
2145 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2146 (board[rf][ff] == cl->piece
2147 || PieceToChar(board[rf][ff]) == '~' &&
2148 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2152 cl->kind = kind; /* this is the move we want */
2154 cl->file++; /* need file to rule out this move */
2158 cl->rank++; /* need rank to rule out this move */
2160 cl->either++; /* rank or file will rule out this move */
2166 /* Convert coordinates to normal algebraic notation.
2167 promoChar must be NULLCHAR or 'x' if not a promotion.
2170 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2174 char *outp = out, c, capture;
2175 CoordsToAlgebraicClosure cl;
2177 if (rf == DROP_RANK) {
2178 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2179 /* Bughouse piece drop */
2180 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2185 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2187 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2190 if (promoChar == 'x') promoChar = NULLCHAR;
2191 piece = board[rf][ff];
2192 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2197 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2198 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2199 /* Keep short notation if move is illegal only because it
2200 leaves the player in check, but still return IllegalMove */
2201 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2202 if (kind == IllegalMove) break;
2207 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2208 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2209 /* Non-capture; use style "e5" */
2212 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2214 /* Capture; use style "exd5" */
2216 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2220 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2222 /* Use promotion suffix style "=Q" */
2224 if (promoChar != NULLCHAR) {
2225 if(IS_SHOGI(gameInfo.variant)) {
2226 /* [HGM] ... but not in Shogi! */
2227 *outp++ = promoChar == '=' ? '=' : '+';
2230 *outp++ = ToUpper(promoChar);
2239 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2240 /* Code added by Tord: FRC castling. */
2241 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2242 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2244 safeStrCpy(out, "O-O", MOVE_LEN);
2246 safeStrCpy(out, "O-O-O", MOVE_LEN);
2247 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2249 /* End of code added by Tord */
2250 /* Test for castling or ICS wild castling */
2251 /* Use style "O-O" (oh-oh) for PGN compatibility */
2252 else if (rf == rt &&
2253 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2254 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2255 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2256 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2257 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2258 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2260 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2262 /* This notation is always unambiguous, unless there are
2263 kings on both the d and e files, with "wild castling"
2264 possible for the king on the d file and normal castling
2265 possible for the other. ICS rules for wild 9
2266 effectively make castling illegal for either king in
2267 this situation. So I am not going to worry about it;
2268 I'll just generate an ambiguous O-O in this case.
2270 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2273 /* else fall through */
2278 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2279 cl.ft = fFilter = ft;
2281 cl.kind = IllegalMove;
2282 cl.rank = cl.file = cl.either = 0;
2283 c = PieceToChar(piece) ;
2284 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2286 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2287 /* Generate pretty moves for moving into check, but
2288 still return IllegalMove.
2290 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2291 if (cl.kind == IllegalMove) break;
2292 cl.kind = IllegalMove;
2295 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2296 else "Ngf3" or "Ngxf7",
2297 else "N1f3" or "N5xf7",
2298 else "Ng1f3" or "Ng5xf7".
2300 if( c == '~' || c == '+') {
2301 /* [HGM] print nonexistent piece as its demoted version */
2302 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2304 if(c=='+') *outp++ = c;
2305 *outp++ = ToUpper(PieceToChar(piece));
2307 if (cl.file || (cl.either && !cl.rank)) {
2313 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2316 if(board[rt][ft] != EmptySquare)
2322 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2323 if (IS_SHOGI(gameInfo.variant)) {
2324 /* [HGM] in Shogi non-pawns can promote */
2325 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2327 else if (gameInfo.variant == VariantChuChess && promoChar ||
2328 gameInfo.variant != VariantSuper && promoChar &&
2329 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2331 *outp++ = ToUpper(promoChar);
2333 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2335 *outp++ = ToUpper(promoChar);
2341 /* Moving a nonexistent piece */
2345 /* Not a legal move, even ignoring check.
2346 If there was a piece on the from square,
2347 use style "Ng1g3" or "Ng1xe8";
2348 if there was a pawn or nothing (!),
2349 use style "g1g3" or "g1xe8". Use "x"
2350 if a piece was on the to square, even
2351 a piece of the same color.
2355 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2357 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2358 c += (board[r][f] == piece); // count on-board pieces of given type
2359 *outp++ = ToUpper(PieceToChar(piece));
2361 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2365 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2367 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2371 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2372 /* Use promotion suffix style "=Q" */
2373 if (promoChar != NULLCHAR && promoChar != 'x') {
2375 *outp++ = ToUpper(promoChar);
2382 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2391 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2393 int preyStackPointer, chaseStackPointer;
2396 unsigned char rf, ff, rt, ft;
2400 unsigned char rank, file;
2406 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2408 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2409 int rf, int ff, int rt, int ft,
2413 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2414 { // For adding captures that can lead to chase indictment to the chaseStack
2415 if(board[rt][ft] == EmptySquare) return; // non-capture
2416 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2417 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2418 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2419 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2420 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2421 chaseStack[chaseStackPointer].rf = rf;
2422 chaseStack[chaseStackPointer].ff = ff;
2423 chaseStack[chaseStackPointer].rt = rt;
2424 chaseStack[chaseStackPointer].ft = ft;
2425 chaseStackPointer++;
2428 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2429 int rf, int ff, int rt, int ft,
2433 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2434 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2436 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2438 if(board[rt][ft] == EmptySquare) return; // no capture
2439 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2440 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2442 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2443 for(i=0; i<chaseStackPointer; i++) {
2444 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2445 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2446 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2447 chaseStack[i] = chaseStack[--chaseStackPointer];
2453 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2454 int rf, int ff, int rt, int ft,
2458 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2459 { // for determining if a piece (given through the closure) is protected
2460 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2462 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2463 if(appData.debugMode && board[rt][ft] != EmptySquare)
2464 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2467 extern char moveList[MAX_MOVES][MOVE_LEN];
2470 PerpetualChase (int first, int last)
2471 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2474 ChessSquare captured;
2476 preyStackPointer = 0; // clear stack of chased pieces
2477 for(i=first; i<last; i+=2) { // for all positions with same side to move
2478 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2479 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2480 // determine all captures possible after the move, and put them on chaseStack
2481 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2482 if(appData.debugMode) { int n;
2483 for(n=0; n<chaseStackPointer; n++)
2484 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2485 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2486 fprintf(debugFP, ": all capts\n");
2488 // determine all captures possible before the move, and delete them from chaseStack
2489 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2490 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2491 cl.rt = moveList[i][3]-ONE;
2492 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2493 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2494 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2495 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2496 if(appData.debugMode) { int n;
2497 for(n=0; n<chaseStackPointer; n++)
2498 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2499 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2500 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2502 // chaseSack now contains all captures made possible by the move
2503 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2504 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2505 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2507 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2508 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2510 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2511 continue; // C or H attack on R is always chase; leave on chaseStack
2513 if(attacker == victim) {
2514 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2515 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2516 // we can capture back with equal piece, so this is no chase but a sacrifice
2517 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2518 j--; /* ! */ continue;
2523 // the attack is on a lower piece, or on a pinned or blocked equal one
2524 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2525 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2526 // test if the victim is protected by a true protector. First make the capture.
2527 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2528 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2529 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2530 // Then test if the opponent can recapture
2531 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2532 cl.rt = chaseStack[j].rt;
2533 cl.ft = chaseStack[j].ft;
2534 if(appData.debugMode) {
2535 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2537 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2538 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2539 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2540 // unmake the capture
2541 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2542 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2543 // if a recapture was found, piece is protected, and we are not chasing it.
2544 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2545 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2549 // chaseStack now contains all moves that chased
2550 if(appData.debugMode) { int n;
2551 for(n=0; n<chaseStackPointer; n++)
2552 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2553 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2554 fprintf(debugFP, ": chases\n");
2556 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2557 for(j=0; j<chaseStackPointer; j++) {
2558 preyStack[j].rank = chaseStack[j].rt;
2559 preyStack[j].file = chaseStack[j].ft;
2561 preyStackPointer = chaseStackPointer;
2564 for(j=0; j<chaseStackPointer; j++) {
2565 for(k=0; k<preyStackPointer; k++) {
2566 // search the victim of each chase move on the preyStack (first occurrence)
2567 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2568 if(k < tail) break; // piece was already identified as still being chased
2569 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2570 preyStack[tail] = preyStack[k]; // by swapping
2571 preyStack[k] = preyStack[preyStackPointer];
2577 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2578 if(appData.debugMode) { int n;
2579 for(n=0; n<preyStackPointer; n++)
2580 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2581 fprintf(debugFP, "always chased upto ply %d\n", i);
2583 // now adjust the location of the chased pieces according to opponent move
2584 for(j=0; j<preyStackPointer; j++) {
2585 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2586 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2587 preyStack[j].rank = moveList[i+1][3]-ONE;
2588 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2593 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2594 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the