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
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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 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
304 int b = dirs2[*desc-'a']; // when alone, use narrow version
305 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
306 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
307 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
308 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
313 if(!dirSet) dirSet = 0xFF;
315 case 'Q': expo = 0; // queen, slide
316 case 'K': all = 0xFF; // non-deg (pseudo) 8-fold
318 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
319 int b = dirs4[*desc-'a']; // when alone, use narrow version
320 if(desc[1] == *desc) desc++; // doubling forces alone
321 else if(islower(desc[1]) && i < '4'
322 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
323 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
328 if(!dirSet) dirSet = (tx < 0 ? 0xFF // default is all directions, but in continuation leg
329 : all == 0xFF ? 0xEF : 0x45); // omits backward, and for 4-fold atoms also diags
330 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
331 ds2 = dirSet & 0xAA; // extract diagonal directions
332 if(dirSet &= 0x55) // start with orthogonal moves, if present
333 retry = 1, dx = 0; // and schedule the diagonal moves for later
334 else dx = dy, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
335 break; // should not have direction indicators
336 default: return; // syntax error: invalid atom
338 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
339 mode = 0; // build mode mask
340 if(*desc == 'm') mode |= 4, desc++; // move to empty
341 if(*desc == 'c') mode |= his, desc++; // capture foe
342 if(*desc == 'd') mode |= mine, desc++; // destroy (capture friend)
343 if(*desc == 'e') mode |= 8, desc++; // e.p. capture last mover
344 if(*desc == 't') mode |= 16, desc++; // exclude enemies as hop platform ('test')
345 if(*desc == 'p') mode |= 32, desc++; // hop over occupied
346 if(*desc == 'g') mode |= 64, desc++; // hop and toggle range
347 if(*desc == 'o') mode |= 128, desc++; // wrap around cylinder board
348 if(*desc == 'y') mode |= 512, desc++; // toggle range on empty square
349 if(*desc == 'n') jump = 0, desc++; // non-jumping
350 while(*desc == 'j') jump++, desc++; // must jump (on B,R,Q: skip first square)
351 if(*desc == 'a') cont = ++desc; // move again after doing what preceded it
352 if(isdigit(*++p)) expo = atoi(p++); // read exponent
353 if(expo > 9) p++; // allow double-digit
354 desc = p; // this is start of next move
355 if(initial && (board[r][f] != initialPosition[r][f] ||
356 r == 0 && board[TOUCHED_W] & 1<<f ||
357 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
358 if(expo > 1 && dx == 0 && dy == 0) { // castling indicated by O + number
359 mode |= 1024; dy = 1;
362 if(!(mode & 15)) mode |= his + 4; // no mode spec, use default = mc
364 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
365 atom = buf; while(islower(*atom)) atom++; // skip to atom
366 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
367 if(mode & 64 + 512) {
368 mode |= 256; // and 'g' too, but converts leaper <-> slider
369 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
370 *atom = upgrade[*atom-'A']; // replace atom, BRQ <-> FWK
371 atom[1] = atom[2] = '\0'; // make sure any old range is stripped off
372 if(expo == 1) atom[1] = '0'; // turn other leapers into riders
374 if(!(mode & 0x30F)) mode |= 4; // and default of this leg = m
376 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
378 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
379 int i = expo, j = skip, hop = mode, vx, vy;
380 if(!(bit & dirSet)) continue; // does not move in this direction
381 if(dy != 1) j = 0; //
382 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
383 vy = dx*rot[dir][2] + dy*rot[dir][3];
384 if(tx < 0) x = f, y = r; // start square
385 else x = tx, y = ty; // from previous to-square if continuation
387 x += vx; y += vy; // step to next square
388 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
389 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT; else break; }
390 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT; else break; }
391 if(j) { j--; continue; } // skip irrespective of occupation
392 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
393 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
394 if(x == f && y == r) occup = 4; else // start square counts as empty
395 if(board[y][x] < BlackPawn) occup = 0x101; else
396 if(board[y][x] < EmptySquare) occup = 0x102; else
398 if(cont) { // non-final leg
399 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
400 if(occup & mode) { // valid intermediate square, do continuation
401 char origAtom = *atom;
402 if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
403 if(occup & mode & 0x104) // no side effects, merge legs to one move
404 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
405 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
407 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
408 if(cnt) { // and if there are
409 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
411 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
415 *atom = origAtom; // undo any interconversion
417 if(occup != 4) break; // occupied squares always terminate the leg
420 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
421 if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
422 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
424 if(mode & 1024) { // castling
425 i = 2; // kludge to elongate move indefinitely
426 if(occup == 4) continue; // skip empty squares
427 if(x == BOARD_LEFT && board[y][x] == initialPosition[y][x]) // reached initial corner piece
428 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
429 if(x == BOARD_RGHT-1 && board[y][x] == initialPosition[y][x])
430 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
433 if(occup & mode) cb(board, flags, NormalMove, r, f, y, x, cl); // allowed, generate
434 if(occup != 4) break; // not valid transit square
437 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
438 } while(retry-- && ds2); // and start doing them
439 if(tx >= 0) break; // don't do other atoms in continuation legs
443 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
446 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
451 if (rt >= BOARD_HEIGHT) break;
452 if (SameColor(board[rf][ff], board[rt][ft])) break;
453 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
454 if (board[rt][ft] != EmptySquare) break;
459 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
465 if (SameColor(board[rf][ff], board[rt][ft])) break;
466 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
467 if (board[rt][ft] != EmptySquare) break;
472 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
474 SlideForward(board, flags, rf, ff, callback, closure);
475 SlideBackward(board, flags, rf, ff, callback, closure);
479 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
481 int i, s, rt = rf, ft;
482 for(s = -1; s <= 1; s+= 2) {
485 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
486 if (SameColor(board[rf][ff], board[rt][ft])) break;
487 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
488 if (board[rt][ft] != EmptySquare) break;
494 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
497 for(s = -1; s <= 1; s+= 2) {
501 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
502 if (SameColor(board[rf][ff], board[rt][ft])) break;
503 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
504 if (board[rt][ft] != EmptySquare) break;
510 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
513 for(s = -1; s <= 1; s+= 2) {
517 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
518 if (SameColor(board[rf][ff], board[rt][ft])) break;
519 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
520 if (board[rt][ft] != EmptySquare) break;
526 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
528 SlideVertical(board, flags, rf, ff, callback, closure);
529 SlideSideways(board, flags, rf, ff, callback, closure);
533 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
535 SlideDiagForward(board, flags, rf, ff, callback, closure);
536 SlideDiagBackward(board, flags, rf, ff, callback, closure);
540 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
541 { // Lion-like move of Horned Falcon and Souring Eagle
542 int ft = ff + dx, rt = rf + dy;
543 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
545 if (!SameColor(board[rf][ff], board[rt][ft]))
546 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
549 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
551 if (!SameColor(board[rf][ff], board[rt][ft]))
552 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
553 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
554 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
559 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
561 int ft = ff, rt = rf + 1;
562 if (rt >= BOARD_HEIGHT) return;
563 if (SameColor(board[rf][ff], board[rt][ft])) return;
564 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
568 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
570 int ft = ff, rt = rf - 1;
572 if (SameColor(board[rf][ff], board[rt][ft])) return;
573 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
577 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
581 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
582 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
584 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
585 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
589 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
592 if (rt >= BOARD_HEIGHT) return;
594 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
595 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
597 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
598 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
602 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
607 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
608 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
610 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
611 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
615 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
617 StepForward(board, flags, rf, ff, callback, closure);
618 StepBackward(board, flags, rf, ff, callback, closure);
622 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
624 StepDiagForward(board, flags, rf, ff, callback, closure);
625 StepDiagBackward(board, flags, rf, ff, callback, closure);
629 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
631 StepVertical(board, flags, rf, ff, callback, closure);
632 StepSideways(board, flags, rf, ff, callback, closure);
636 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
639 for (i = -1; i <= 1; i += 2)
640 for (j = -1; j <= 1; j += 2)
641 for (s = 1; s <= 2; s++) {
644 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
645 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
646 && !SameColor(board[rf][ff], board[rt][ft]))
647 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
651 /* Call callback once for each pseudo-legal move in the given
652 position, except castling moves. A move is pseudo-legal if it is
653 legal, or if it would be legal except that it leaves the king in
654 check. In the arguments, epfile is EP_NONE if the previous move
655 was not a double pawn push, or the file 0..7 if it was, or
656 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
657 Promotion moves generated are to Queen only.
660 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
661 // speed: only do moves with this piece type
664 int i, j, d, s, fs, rs, rt, ft, m;
665 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
666 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
668 for (rf = 0; rf < BOARD_HEIGHT; rf++)
669 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
672 if(board[rf][ff] == EmptySquare) continue;
673 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
674 m = 0; piece = board[rf][ff];
675 if(PieceToChar(piece) == '~')
676 piece = (ChessSquare) ( DEMOTED piece );
677 if(filter != EmptySquare && piece != filter) continue;
678 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
679 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
682 if(IS_SHOGI(gameInfo.variant))
683 piece = (ChessSquare) ( SHOGI piece );
685 switch ((int)piece) {
686 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
688 /* can't happen ([HGM] except for faries...) */
692 if(gameInfo.variant == VariantXiangqi) {
693 /* [HGM] capture and move straight ahead in Xiangqi */
694 if (rf < BOARD_HEIGHT-1 &&
695 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
696 callback(board, flags, NormalMove,
697 rf, ff, rf + 1, ff, closure);
699 /* and move sideways when across the river */
700 for (s = -1; s <= 1; s += 2) {
701 if (rf >= BOARD_HEIGHT>>1 &&
702 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
703 !WhitePiece(board[rf][ff+s]) ) {
704 callback(board, flags, NormalMove,
705 rf, ff, rf, ff+s, closure);
710 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
711 callback(board, flags,
712 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
713 rf, ff, rf + 1, ff, closure);
715 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
716 gameInfo.variant != VariantShatranj && /* [HGM] */
717 gameInfo.variant != VariantCourier && /* [HGM] */
718 board[rf+2][ff] == EmptySquare ) {
719 callback(board, flags, NormalMove,
720 rf, ff, rf+2, ff, closure);
722 for (s = -1; s <= 1; s += 2) {
723 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
724 ((flags & F_KRIEGSPIEL_CAPTURE) ||
725 BlackPiece(board[rf + 1][ff + s]))) {
726 callback(board, flags,
727 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
728 rf, ff, rf + 1, ff + s, closure);
730 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
731 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
732 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
733 board[rf][ff + s] == BlackPawn &&
734 board[rf+1][ff + s] == EmptySquare) {
735 callback(board, flags, WhiteCapturesEnPassant,
736 rf, ff, rf+1, ff + s, closure);
743 if(gameInfo.variant == VariantXiangqi) {
744 /* [HGM] capture straight ahead in Xiangqi */
745 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
746 callback(board, flags, NormalMove,
747 rf, ff, rf - 1, ff, closure);
749 /* and move sideways when across the river */
750 for (s = -1; s <= 1; s += 2) {
751 if (rf < BOARD_HEIGHT>>1 &&
752 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
753 !BlackPiece(board[rf][ff+s]) ) {
754 callback(board, flags, NormalMove,
755 rf, ff, rf, ff+s, closure);
760 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
761 callback(board, flags,
762 rf <= promoRank ? BlackPromotion : NormalMove,
763 rf, ff, rf - 1, ff, closure);
765 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
766 gameInfo.variant != VariantShatranj && /* [HGM] */
767 gameInfo.variant != VariantCourier && /* [HGM] */
768 board[rf-2][ff] == EmptySquare) {
769 callback(board, flags, NormalMove,
770 rf, ff, rf-2, ff, closure);
772 for (s = -1; s <= 1; s += 2) {
773 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
774 ((flags & F_KRIEGSPIEL_CAPTURE) ||
775 WhitePiece(board[rf - 1][ff + s]))) {
776 callback(board, flags,
777 rf <= promoRank ? BlackPromotion : NormalMove,
778 rf, ff, rf - 1, ff + s, closure);
780 if (rf < BOARD_HEIGHT>>1) {
781 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
782 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
783 board[rf][ff + s] == WhitePawn &&
784 board[rf-1][ff + s] == EmptySquare) {
785 callback(board, flags, BlackCapturesEnPassant,
786 rf, ff, rf-1, ff + s, closure);
796 for (i = -1; i <= 1; i += 2)
797 for (j = -1; j <= 1; j += 2)
798 for (s = 1; s <= 2; s++) {
801 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
802 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
803 && !SameColor(board[rf][ff], board[rt][ft]))
804 callback(board, flags, NormalMove,
805 rf, ff, rt, ft, closure);
809 case SHOGI WhiteKnight:
810 for (s = -1; s <= 1; s += 2) {
811 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
812 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
813 callback(board, flags, NormalMove,
814 rf, ff, rf + 2, ff + s, closure);
819 case SHOGI BlackKnight:
820 for (s = -1; s <= 1; s += 2) {
821 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
822 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
823 callback(board, flags, NormalMove,
824 rf, ff, rf - 2, ff + s, closure);
831 for (d = 0; d <= 1; d++)
832 for (s = -1; s <= 1; s += 2) {
835 rt = rf + (i * s) * d;
836 ft = ff + (i * s) * (1 - d);
837 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
838 if (m == 0 && board[rt][ft] == EmptySquare)
839 callback(board, flags, NormalMove,
840 rf, ff, rt, ft, closure);
841 if (m == 1 && board[rt][ft] != EmptySquare &&
842 !SameColor(board[rf][ff], board[rt][ft]) )
843 callback(board, flags, NormalMove,
844 rf, ff, rt, ft, closure);
845 if (board[rt][ft] != EmptySquare && m++) break;
850 /* Gold General (and all its promoted versions) . First do the */
851 /* diagonal forward steps, then proceed as normal Wazir */
852 case SHOGI (PROMOTED WhitePawn):
853 if(gameInfo.variant == VariantShogi) goto WhiteGold;
854 case SHOGI (PROMOTED BlackPawn):
855 if(gameInfo.variant == VariantShogi) goto BlackGold;
856 SlideVertical(board, flags, rf, ff, callback, closure);
859 case SHOGI (PROMOTED WhiteKnight):
860 if(gameInfo.variant == VariantShogi) goto WhiteGold;
861 case SHOGI BlackDrunk:
862 case SHOGI BlackAlfil:
863 Ferz(board, flags, rf, ff, callback, closure);
864 StepSideways(board, flags, rf, ff, callback, closure);
865 StepBackward(board, flags, rf, ff, callback, closure);
868 case SHOGI (PROMOTED BlackKnight):
869 if(gameInfo.variant == VariantShogi) goto BlackGold;
870 case SHOGI WhiteDrunk:
871 case SHOGI WhiteAlfil:
872 Ferz(board, flags, rf, ff, callback, closure);
873 StepSideways(board, flags, rf, ff, callback, closure);
874 StepForward(board, flags, rf, ff, callback, closure);
878 case SHOGI WhiteStag:
879 case SHOGI BlackStag:
880 if(gameInfo.variant == VariantShogi) goto BlackGold;
881 SlideVertical(board, flags, rf, ff, callback, closure);
882 Ferz(board, flags, rf, ff, callback, closure);
883 StepSideways(board, flags, rf, ff, callback, closure);
886 case SHOGI (PROMOTED WhiteQueen):
887 case SHOGI WhiteTokin:
888 case SHOGI WhiteWazir:
890 StepDiagForward(board, flags, rf, ff, callback, closure);
891 Wazir(board, flags, rf, ff, callback, closure);
894 case SHOGI (PROMOTED BlackQueen):
895 case SHOGI BlackTokin:
896 case SHOGI BlackWazir:
898 StepDiagBackward(board, flags, rf, ff, callback, closure);
899 Wazir(board, flags, rf, ff, callback, closure);
904 Wazir(board, flags, rf, ff, callback, closure);
907 case SHOGI WhiteMarshall:
908 case SHOGI BlackMarshall:
909 Ferz(board, flags, rf, ff, callback, closure);
910 for (d = 0; d <= 1; d++)
911 for (s = -2; s <= 2; s += 4) {
913 ft = ff + s * (1 - d);
914 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
915 if (!SameColor(board[rf][ff], board[rt][ft]) )
916 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
920 case SHOGI WhiteAngel:
921 case SHOGI BlackAngel:
922 Wazir(board, flags, rf, ff, callback, closure);
926 /* [HGM] support Shatranj pieces */
927 for (rs = -1; rs <= 1; rs += 2)
928 for (fs = -1; fs <= 1; fs += 2) {
931 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
932 && ( gameInfo.variant != VariantXiangqi ||
933 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
935 && !SameColor(board[rf][ff], board[rt][ft]))
936 callback(board, flags, NormalMove,
937 rf, ff, rt, ft, closure);
938 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
939 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
940 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
942 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
943 && !SameColor(board[rf][ff], board[rt][ft]))
944 callback(board, flags, NormalMove,
945 rf, ff, rt, ft, closure);
947 if(gameInfo.variant == VariantSpartan)
948 for(fs = -1; fs <= 1; fs += 2) {
950 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
951 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
955 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
958 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
959 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
960 for (s = -2; s <= 2; s += 4) {
962 ft = ff + s * (1 - d);
963 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
964 if (SameColor(board[rf][ff], board[rt][ft])) continue;
965 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
968 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
969 case SHOGI WhiteCardinal:
970 case SHOGI BlackCardinal:
971 case SHOGI WhitePCardinal:
972 case SHOGI BlackPCardinal:
974 Bishop(board, flags, rf, ff, callback, closure);
975 Wazir(board, flags, rf, ff, callback, closure);
978 /* Capablanca Archbishop continues as Knight */
981 Knight(board, flags, rf, ff, callback, closure);
983 /* Shogi Bishops are ordinary Bishops */
984 case SHOGI WhiteBishop:
985 case SHOGI BlackBishop:
986 case SHOGI WhitePBishop:
987 case SHOGI BlackPBishop:
990 Bishop(board, flags, rf, ff, callback, closure);
993 /* Shogi Lance is unlike anything, and asymmetric at that */
994 case SHOGI WhiteQueen:
995 if(gameInfo.variant == VariantChu) goto doQueen;
999 if (rt >= BOARD_HEIGHT) break;
1000 if (SameColor(board[rf][ff], board[rt][ft])) break;
1001 callback(board, flags, NormalMove,
1002 rf, ff, rt, ft, closure);
1003 if (board[rt][ft] != EmptySquare) break;
1007 case SHOGI BlackQueen:
1008 if(gameInfo.variant == VariantChu) goto doQueen;
1013 if (SameColor(board[rf][ff], board[rt][ft])) break;
1014 callback(board, flags, NormalMove,
1015 rf, ff, rt, ft, closure);
1016 if (board[rt][ft] != EmptySquare) break;
1020 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1023 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1024 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1025 for (s = -2; s <= 2; s += 4) {
1027 ft = ff + s * (1 - d);
1028 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1029 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1030 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1031 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1033 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1034 Wazir(board, flags, rf, ff, callback, closure);
1036 Rook(board, flags, rf, ff, callback, closure);
1039 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1040 case SHOGI WhiteDragon:
1041 case SHOGI BlackDragon:
1042 case SHOGI WhitePDragon:
1043 case SHOGI BlackPDragon:
1045 Rook(board, flags, rf, ff, callback, closure);
1046 Ferz(board, flags, rf, ff, callback, closure);
1050 /* Capablanca Chancellor sets flag to continue as Knight */
1053 Rook(board, flags, rf, ff, callback, closure);
1054 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1055 Ferz(board, flags, rf, ff, callback, closure);
1057 Knight(board, flags, rf, ff, callback, closure);
1060 /* Shogi Rooks are ordinary Rooks */
1061 case SHOGI WhiteRook:
1062 case SHOGI BlackRook:
1063 case SHOGI WhitePRook:
1064 case SHOGI BlackPRook:
1067 Rook(board, flags, rf, ff, callback, closure);
1072 case SHOGI WhiteMother:
1073 case SHOGI BlackMother:
1075 Rook(board, flags, rf, ff, callback, closure);
1076 Bishop(board, flags, rf, ff, callback, closure);
1079 case SHOGI WhitePawn:
1080 StepForward(board, flags, rf, ff, callback, closure);
1083 case SHOGI BlackPawn:
1084 StepBackward(board, flags, rf, ff, callback, closure);
1088 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1089 case SHOGI WhiteFerz:
1090 Ferz(board, flags, rf, ff, callback, closure);
1091 StepForward(board, flags, rf, ff, callback, closure);
1095 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1096 case SHOGI BlackFerz:
1097 StepBackward(board, flags, rf, ff, callback, closure);
1101 /* [HGM] support Shatranj pieces */
1102 Ferz(board, flags, rf, ff, callback, closure);
1107 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1110 case SHOGI WhiteMonarch:
1111 case SHOGI BlackMonarch:
1112 case SHOGI WhiteKing:
1113 case SHOGI BlackKing:
1116 Ferz(board, flags, rf, ff, callback, closure);
1117 Wazir(board, flags, rf, ff, callback, closure);
1120 case WhiteNightrider:
1121 case BlackNightrider:
1122 for (i = -1; i <= 1; i += 2)
1123 for (j = -1; j <= 1; j += 2)
1124 for (s = 1; s <= 2; s++) { int k;
1127 ft = ff + k*j*(3-s);
1128 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1129 if (SameColor(board[rf][ff], board[rt][ft])) break;
1130 callback(board, flags, NormalMove,
1131 rf, ff, rt, ft, closure);
1132 if (board[rt][ft] != EmptySquare) break;
1138 Bishop(board, flags, rf, ff, callback, closure);
1139 Rook(board, flags, rf, ff, callback, closure);
1140 Knight(board, flags, rf, ff, callback, closure);
1143 // Use Lance as Berolina / Spartan Pawn.
1145 if(gameInfo.variant == VariantSuper) goto Amazon;
1146 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1147 callback(board, flags,
1148 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1149 rf, ff, rf + 1, ff, closure);
1150 for (s = -1; s <= 1; s += 2) {
1151 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1152 callback(board, flags,
1153 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1154 rf, ff, rf + 1, ff + s, closure);
1155 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1156 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1161 if(gameInfo.variant == VariantSuper) goto Amazon;
1162 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1163 callback(board, flags,
1164 rf <= promoRank ? BlackPromotion : NormalMove,
1165 rf, ff, rf - 1, ff, closure);
1166 for (s = -1; s <= 1; s += 2) {
1167 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1168 callback(board, flags,
1169 rf <= promoRank ? BlackPromotion : NormalMove,
1170 rf, ff, rf - 1, ff + s, closure);
1171 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1172 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1176 case SHOGI WhiteNothing:
1177 case SHOGI BlackNothing:
1178 case SHOGI WhiteLion:
1179 case SHOGI BlackLion:
1182 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1183 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1184 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1185 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1186 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1187 rf, ff, rt, ft, closure);
1192 case SHOGI WhiteFalcon:
1193 case SHOGI BlackFalcon:
1194 case SHOGI WhitePDagger:
1195 case SHOGI BlackPDagger:
1196 SlideSideways(board, flags, rf, ff, callback, closure);
1197 StepVertical(board, flags, rf, ff, callback, closure);
1200 case SHOGI WhiteCobra:
1201 case SHOGI BlackCobra:
1202 StepVertical(board, flags, rf, ff, callback, closure);
1205 case SHOGI (PROMOTED WhiteFerz):
1206 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1207 case SHOGI (PROMOTED BlackFerz):
1208 if(gameInfo.variant == VariantShogi) goto BlackGold;
1209 case SHOGI WhitePSword:
1210 case SHOGI BlackPSword:
1211 SlideVertical(board, flags, rf, ff, callback, closure);
1212 StepSideways(board, flags, rf, ff, callback, closure);
1215 case SHOGI WhiteUnicorn:
1216 case SHOGI BlackUnicorn:
1217 Ferz(board, flags, rf, ff, callback, closure);
1218 StepVertical(board, flags, rf, ff, callback, closure);
1221 case SHOGI WhiteMan:
1222 StepDiagForward(board, flags, rf, ff, callback, closure);
1223 StepVertical(board, flags, rf, ff, callback, closure);
1226 case SHOGI BlackMan:
1227 StepDiagBackward(board, flags, rf, ff, callback, closure);
1228 StepVertical(board, flags, rf, ff, callback, closure);
1231 case SHOGI WhiteHCrown:
1232 case SHOGI BlackHCrown:
1233 Bishop(board, flags, rf, ff, callback, closure);
1234 SlideSideways(board, flags, rf, ff, callback, closure);
1237 case SHOGI WhiteCrown:
1238 case SHOGI BlackCrown:
1239 Bishop(board, flags, rf, ff, callback, closure);
1240 SlideVertical(board, flags, rf, ff, callback, closure);
1243 case SHOGI WhiteHorned:
1244 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1245 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1246 if(killX >= 0) break;
1247 Bishop(board, flags, rf, ff, callback, closure);
1248 SlideSideways(board, flags, rf, ff, callback, closure);
1249 SlideBackward(board, flags, rf, ff, callback, closure);
1252 case SHOGI BlackHorned:
1253 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1254 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1255 if(killX >= 0) break;
1256 Bishop(board, flags, rf, ff, callback, closure);
1257 SlideSideways(board, flags, rf, ff, callback, closure);
1258 SlideForward(board, flags, rf, ff, callback, closure);
1261 case SHOGI WhiteEagle:
1262 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1263 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1264 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1265 if(killX >= 0) break;
1266 Rook(board, flags, rf, ff, callback, closure);
1267 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1270 case SHOGI BlackEagle:
1271 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1272 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1273 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1274 if(killX >= 0) break;
1275 Rook(board, flags, rf, ff, callback, closure);
1276 SlideDiagForward(board, flags, rf, ff, callback, closure);
1279 case SHOGI WhiteDolphin:
1280 case SHOGI BlackHorse:
1281 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1282 SlideVertical(board, flags, rf, ff, callback, closure);
1285 case SHOGI BlackDolphin:
1286 case SHOGI WhiteHorse:
1287 SlideDiagForward(board, flags, rf, ff, callback, closure);
1288 SlideVertical(board, flags, rf, ff, callback, closure);
1291 case SHOGI WhiteLance:
1292 SlideForward(board, flags, rf, ff, callback, closure);
1295 case SHOGI BlackLance:
1296 SlideBackward(board, flags, rf, ff, callback, closure);
1299 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1303 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1316 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1317 Board xqCheckers, nullBoard;
1319 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1320 int rf, int ff, int rt, int ft,
1324 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1326 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1328 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1330 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1332 if (!(flags & F_IGNORE_CHECK) ) {
1333 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1336 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1337 kings += (board[r][f] == BlackKing);
1341 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1343 check = CheckTest(board, flags, rf, ff, rt, ft,
1344 kind == WhiteCapturesEnPassant ||
1345 kind == BlackCapturesEnPassant);
1346 if(promo) board[rf][ff] = BlackLance;
1349 if (flags & F_ATOMIC_CAPTURE) {
1350 if (board[rt][ft] != EmptySquare ||
1351 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1353 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1354 if (board[rf][ff] == king) return;
1355 for (r = rt-1; r <= rt+1; r++) {
1356 for (f = ft-1; f <= ft+1; f++) {
1357 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1358 board[r][f] == king) return;
1363 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1370 int captures; // [HGM] losers
1371 } LegalityTestClosure;
1374 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1375 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1376 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1377 moves that would destroy your own king. The CASTLE_OK flags are
1378 true if castling is not yet ruled out by a move of the king or
1379 rook. Return TRUE if the player on move is currently in check and
1380 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1382 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1385 int ff, ft, k, left, right, swap;
1386 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1387 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1388 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1393 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1394 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1395 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1397 if (inCheck) return TRUE;
1399 /* Generate castling moves */
1400 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1401 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1404 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1405 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1407 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1408 if ((flags & F_WHITE_ON_MOVE) &&
1409 (flags & F_WHITE_KCASTLE_OK) &&
1410 board[0][ff] == wKing &&
1411 board[0][ff + 1] == EmptySquare &&
1412 board[0][ff + 2] == EmptySquare &&
1413 board[0][BOARD_RGHT-3] == EmptySquare &&
1414 board[0][BOARD_RGHT-2] == EmptySquare &&
1415 board[0][BOARD_RGHT-1] == WhiteRook &&
1416 castlingRights[0] != NoRights && /* [HGM] check rights */
1417 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1419 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1420 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1421 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1422 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1424 callback(board, flags,
1425 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1426 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1428 if ((flags & F_WHITE_ON_MOVE) &&
1429 (flags & F_WHITE_QCASTLE_OK) &&
1430 board[0][ff] == wKing &&
1431 board[0][ff - 1] == EmptySquare &&
1432 board[0][ff - 2] == EmptySquare &&
1433 board[0][BOARD_LEFT+2] == EmptySquare &&
1434 board[0][BOARD_LEFT+1] == EmptySquare &&
1435 board[0][BOARD_LEFT+0] == WhiteRook &&
1436 castlingRights[1] != NoRights && /* [HGM] check rights */
1437 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1439 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1440 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1441 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1443 callback(board, flags,
1444 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1445 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1447 if (!(flags & F_WHITE_ON_MOVE) &&
1448 (flags & F_BLACK_KCASTLE_OK) &&
1449 board[BOARD_HEIGHT-1][ff] == bKing &&
1450 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1451 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1452 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1453 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1454 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1455 castlingRights[3] != NoRights && /* [HGM] check rights */
1456 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1458 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1459 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1460 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1461 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1463 callback(board, flags,
1464 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1465 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1467 if (!(flags & F_WHITE_ON_MOVE) &&
1468 (flags & F_BLACK_QCASTLE_OK) &&
1469 board[BOARD_HEIGHT-1][ff] == bKing &&
1470 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1471 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1472 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1473 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1474 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1475 castlingRights[4] != NoRights && /* [HGM] check rights */
1476 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1478 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1479 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1480 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1482 callback(board, flags,
1483 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1484 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1488 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1490 /* generate all potential FRC castling moves (KxR), ignoring flags */
1491 /* [HGM] test if the Rooks we find have castling rights */
1492 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1495 if ((flags & F_WHITE_ON_MOVE) != 0) {
1496 ff = castlingRights[2]; /* King file if we have any rights */
1497 if(ff != NoRights && board[0][ff] == WhiteKing) {
1498 if (appData.debugMode) {
1499 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1500 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1502 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1504 right = BOARD_RGHT-2;
1505 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1506 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1507 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1508 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1509 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1510 if(ft != NoRights && board[0][ft] == WhiteRook) {
1511 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1512 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1515 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1516 left = BOARD_LEFT+2;
1518 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1519 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1520 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1521 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1522 if(ff > BOARD_LEFT+2)
1523 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1524 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1525 if(ft != NoRights && board[0][ft] == WhiteRook) {
1526 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1527 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1531 ff = castlingRights[5]; /* King file if we have any rights */
1532 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1533 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1535 right = BOARD_RGHT-2;
1536 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1537 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1538 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1539 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1540 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1541 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1542 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1543 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1546 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1547 left = BOARD_LEFT+2;
1549 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1550 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1551 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1552 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1553 if(ff > BOARD_LEFT+2)
1554 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1555 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1556 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1557 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1558 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1575 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1576 int rf, int ff, int rt, int ft,
1581 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1583 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1585 if (rt == cl->rking && ft == cl->fking) {
1586 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1588 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1590 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1591 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1592 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1596 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1597 he leave himself in check? Or if rf == -1, is the player on move
1598 in check now? enPassant must be TRUE if the indicated move is an
1599 e.p. capture. The possibility of castling out of a check along the
1600 back rank is not accounted for (i.e., we still return nonzero), as
1601 this is illegal anyway. Return value is the number of times the
1602 king is in check. */
1604 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1606 CheckTestClosure cl;
1607 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1608 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1609 /* Suppress warnings on uninitialized variables */
1611 if(gameInfo.variant == VariantXiangqi)
1612 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1613 if(gameInfo.variant == VariantKnightmate)
1614 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1615 if(gameInfo.variant == VariantChu) { // strictly speaking this is not needed, as Chu officially has no check
1616 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1617 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1618 if(board[r][f] == k || board[r][f] == prince) {
1619 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1620 king = board[r][f]; // remember hich one we had
1627 captured = board[rf][ft];
1628 board[rf][ft] = EmptySquare;
1630 captured = board[rt][ft];
1631 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; }
1633 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1634 board[rt][ft] = board[rf][ff];
1635 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1637 ep = board[EP_STATUS];
1638 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1639 ChessSquare victim = killX < 0 ? EmptySquare : trampled;
1640 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1641 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1642 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn) ) // no or worthless 'bridge'
1643 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1647 /* For compatibility with ICS wild 9, we scan the board in the
1648 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1649 and we test only whether that one is in check. */
1650 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1651 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1652 if (board[cl.rking][cl.fking] == king) {
1654 if(gameInfo.variant == VariantXiangqi) {
1655 /* [HGM] In Xiangqi opposing Kings means check as well */
1657 dir = (king >= BlackPawn) ? -1 : 1;
1658 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1659 board[i][cl.fking] == EmptySquare; i+=dir );
1660 if(i>=0 && i<BOARD_HEIGHT &&
1661 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1664 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1665 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1666 goto undo_move; /* 2-level break */
1673 if(rf != DROP_RANK) // [HGM] drop
1674 board[rf][ff] = board[rt][ft];
1676 board[rf][ft] = captured;
1677 board[rt][ft] = EmptySquare;
1679 if(killX >= 0) board[killY][killX] = trampled;
1680 board[rt][ft] = captured;
1682 board[EP_STATUS] = ep;
1685 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1689 HasLion (Board board, int flags)
1691 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1693 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1694 if(board[r][f] == lion) return 1;
1699 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1700 { // [HGM] put drop legality testing in separate routine for clarity
1702 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1703 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1704 n = PieceToNumber(piece);
1705 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1706 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1707 return ImpossibleMove; // piece not available
1708 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1709 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1710 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1711 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1712 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1713 if(piece == WhitePawn || piece == BlackPawn) {
1714 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1715 for(r=1; r<BOARD_HEIGHT-1; r++)
1716 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1717 // should still test if we mate with this Pawn
1719 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1720 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1722 if( (piece == WhitePawn || piece == BlackPawn) &&
1723 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1724 return IllegalMove; /* no pawn drops on 1st/8th */
1726 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1727 if (!(flags & F_IGNORE_CHECK) &&
1728 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1729 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1732 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1733 int rf, int ff, int rt, int ft,
1737 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1739 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1741 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1742 cl->captures++; // [HGM] losers: count legal captures
1743 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1748 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1750 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1752 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1753 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1754 piece = filterPiece = board[rf][ff];
1755 if(PieceToChar(piece) == '~') filterPiece = DEMOTED piece;
1757 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1758 /* (perhaps we should disallow moves that obviously leave us in check?) */
1759 if((piece == WhiteFalcon || piece == BlackFalcon ||
1760 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1761 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1765 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1766 cl.ft = fFilter = ft;
1767 cl.kind = IllegalMove;
1768 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1769 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1770 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1771 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1772 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1773 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1775 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1776 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1777 if(board[rf][ff] < BlackPawn) { // white
1778 if(rf != 0) return IllegalMove; // must be on back rank
1779 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1780 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1781 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1782 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1784 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1785 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1786 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1787 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1788 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1791 if(gameInfo.variant == VariantChu) {
1792 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1793 if(promoChar != '+')
1794 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1795 if(PieceToChar(CHUPROMOTED board[rf][ff]) != '+') return ImpossibleMove;
1796 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1798 if(gameInfo.variant == VariantShogi) {
1799 /* [HGM] Shogi promotions. '=' means defer */
1800 if(rf != DROP_RANK && cl.kind == NormalMove) {
1801 ChessSquare piece = board[rf][ff];
1803 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1804 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1805 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1806 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1807 promoChar = '+'; // allowed ICS notations
1808 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1809 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1810 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1811 else if(flags & F_WHITE_ON_MOVE) {
1812 if( (int) piece < (int) WhiteWazir &&
1813 (rf >= BOARD_HEIGHT - BOARD_HEIGHT/3 || rt >= BOARD_HEIGHT - BOARD_HEIGHT/3) ) {
1814 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1815 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1816 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1817 else /* promotion optional, default is defer */
1818 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1819 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1821 if( (int) piece < (int) BlackWazir && (rf < BOARD_HEIGHT/3 || rt < BOARD_HEIGHT/3) ) {
1822 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1823 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1824 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1825 else /* promotion optional, default is defer */
1826 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1827 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1831 if (promoChar != NULLCHAR) {
1832 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1833 ChessSquare piece = board[rf][ff];
1834 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1835 // should test if in zone, really
1836 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1838 if(PieceToChar(PROMOTED piece) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1840 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1841 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1842 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1843 if(piece == EmptySquare)
1844 cl.kind = ImpossibleMove; // non-existing piece
1845 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1846 cl.kind = IllegalMove; // no two Lions
1847 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1848 if(promoChar != PieceToChar(BlackKing)) {
1849 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1850 if(piece == BlackLance) cl.kind = ImpossibleMove;
1851 } else { // promotion to King allowed only if we do not have two yet
1852 int r, f, kings = 0;
1853 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1854 if(kings == 2) cl.kind = IllegalMove;
1856 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1857 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1858 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1859 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1860 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1861 cl.kind = IllegalMove; // promotion to King usually not allowed
1863 cl.kind = IllegalMove;
1873 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1874 int rf, int ff, int rt, int ft,
1878 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1880 register MateTestClosure *cl = (MateTestClosure *) closure;
1885 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1887 MateTest (Board board, int flags)
1890 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1891 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1893 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1894 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1895 nrKing += (board[r][f] == king); // stm has king
1896 if( board[r][f] != EmptySquare ) {
1897 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1902 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1903 case VariantShatranj:
1904 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1908 if(nrKing == 0) return MT_NOKING;
1911 if(myPieces == 1) return MT_BARE;
1914 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1915 // [HGM] 3check: yet to do!
1917 return inCheck ? MT_CHECK : MT_NONE;
1919 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1920 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
1921 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
1922 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
1923 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
1924 if(board[n][holdings] != EmptySquare) {
1925 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
1926 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
1929 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
1930 return myPieces == hisPieces ? MT_STALEMATE :
1931 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
1932 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
1933 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
1935 return inCheck ? MT_CHECKMATE
1936 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
1937 MT_STAINMATE : MT_STALEMATE;
1942 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
1943 int rf, int ff, int rt, int ft,
1947 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1949 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
1950 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
1952 // [HGM] wild: for wild-card pieces rt and rf are dummies
1953 if(piece == WhiteFalcon || piece == BlackFalcon ||
1954 piece == WhiteCobra || piece == BlackCobra)
1957 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
1958 || PieceToChar(board[rf][ff]) == '~'
1959 && cl->pieceIn == (ChessSquare)(DEMOTED board[rf][ff])
1961 (cl->rfIn == -1 || cl->rfIn == rf) &&
1962 (cl->ffIn == -1 || cl->ffIn == ff) &&
1963 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
1964 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
1966 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
1969 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
1970 // [HGM] oneclick: if multiple moves, be sure we remember capture
1971 cl->piece = board[rf][ff];
1974 cl->rt = wildCard ? cl->rtIn : rt;
1975 cl->ft = wildCard ? cl->ftIn : ft;
1978 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
1983 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
1985 int illegal = 0; char c = closure->promoCharIn;
1987 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1988 closure->count = closure->captures = 0;
1989 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1990 closure->kind = ImpossibleMove;
1991 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
1992 fFilter = closure->ftIn;
1993 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
1994 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
1995 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
1996 closure->count = closure->captures = 0;
1997 closure->rf = closure->ff = closure->rt = closure->ft = 0;
1998 closure->kind = ImpossibleMove;
1999 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2002 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2003 if (closure->count == 0) {
2004 /* See if it's an illegal move due to check */
2006 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2007 if (closure->count == 0) {
2008 /* No, it's not even that */
2009 if(!appData.testLegality && closure->pieceIn != EmptySquare) {
2010 int f, r; // if there is only a single piece of the requested type on the board, use that
2011 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2012 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2013 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2014 if(closure->count > 1) illegal = 0; // ambiguous
2016 if(closure->count == 0) {
2017 if (appData.debugMode) { int i, j;
2018 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2019 for(j=0; j<BOARD_WIDTH; j++)
2020 fprintf(debugFP, "%3d", (int) board[i][j]);
2021 fprintf(debugFP, "\n");
2027 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2028 DisambiguateClosure spare = *closure;
2029 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2030 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2031 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2035 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2036 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2037 if(closure->piece < BlackPawn) { // white
2038 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2039 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2040 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2041 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2042 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2044 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2045 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2046 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2047 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2048 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2051 if(gameInfo.variant == VariantChu) {
2052 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2054 if(gameInfo.variant == VariantShogi) {
2055 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2056 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2057 ChessSquare piece = closure->piece;
2058 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2059 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2060 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2061 c = '+'; // allowed ICS notations
2062 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2063 else if(flags & F_WHITE_ON_MOVE) {
2064 if( (int) piece < (int) WhiteWazir &&
2065 (closure->rf >= BOARD_HEIGHT-(BOARD_HEIGHT/3) || closure->rt >= BOARD_HEIGHT-(BOARD_HEIGHT/3)) ) {
2066 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2067 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2068 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2069 else /* promotion optional, default is defer */
2070 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2071 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2073 if( (int) piece < (int) BlackWazir && (closure->rf < BOARD_HEIGHT/3 || closure->rt < BOARD_HEIGHT/3) ) {
2074 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2075 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2076 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2077 else /* promotion optional, default is defer */
2078 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2079 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2082 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2083 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2085 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2086 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2087 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2088 gameInfo.variant == VariantMakruk || gameInfo.variant == VariantASEAN)
2089 c = PieceToChar(BlackFerz);
2090 else if(gameInfo.variant == VariantGreat)
2091 c = PieceToChar(BlackMan);
2092 else if(gameInfo.variant == VariantGrand)
2093 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2095 c = PieceToChar(BlackQueen);
2096 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2097 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2098 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2099 ChessSquare p = closure->piece;
2100 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED p) != '+')
2101 closure->kind = ImpossibleMove; // used on non-promotable piece
2102 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2103 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2105 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2106 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2107 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2108 if (closure->count > 1) {
2109 closure->kind = AmbiguousMove;
2112 /* Note: If more than one illegal move matches, but no legal
2113 moves, we return IllegalMove, not AmbiguousMove. Caller
2114 can look at closure->count to detect this.
2116 closure->kind = IllegalMove;
2130 } CoordsToAlgebraicClosure;
2132 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2133 ChessMove kind, int rf, int ff,
2134 int rt, int ft, VOIDSTAR closure));
2137 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2139 register CoordsToAlgebraicClosure *cl =
2140 (CoordsToAlgebraicClosure *) closure;
2142 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2143 (board[rf][ff] == cl->piece
2144 || PieceToChar(board[rf][ff]) == '~' &&
2145 (ChessSquare) (DEMOTED board[rf][ff]) == cl->piece)
2149 cl->kind = kind; /* this is the move we want */
2151 cl->file++; /* need file to rule out this move */
2155 cl->rank++; /* need rank to rule out this move */
2157 cl->either++; /* rank or file will rule out this move */
2163 /* Convert coordinates to normal algebraic notation.
2164 promoChar must be NULLCHAR or 'x' if not a promotion.
2167 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2171 char *outp = out, c, capture;
2172 CoordsToAlgebraicClosure cl;
2174 if (rf == DROP_RANK) {
2175 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2176 /* Bughouse piece drop */
2177 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2182 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2184 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2187 if (promoChar == 'x') promoChar = NULLCHAR;
2188 piece = board[rf][ff];
2189 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED piece);
2194 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2195 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2196 /* Keep short notation if move is illegal only because it
2197 leaves the player in check, but still return IllegalMove */
2198 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2199 if (kind == IllegalMove) break;
2204 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2205 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2206 /* Non-capture; use style "e5" */
2209 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2211 /* Capture; use style "exd5" */
2213 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2217 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2219 /* Use promotion suffix style "=Q" */
2221 if (promoChar != NULLCHAR) {
2222 if(IS_SHOGI(gameInfo.variant)) {
2223 /* [HGM] ... but not in Shogi! */
2224 *outp++ = promoChar == '=' ? '=' : '+';
2227 *outp++ = ToUpper(promoChar);
2236 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2237 /* Code added by Tord: FRC castling. */
2238 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2239 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2241 safeStrCpy(out, "O-O", MOVE_LEN);
2243 safeStrCpy(out, "O-O-O", MOVE_LEN);
2244 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2246 /* End of code added by Tord */
2247 /* Test for castling or ICS wild castling */
2248 /* Use style "O-O" (oh-oh) for PGN compatibility */
2249 else if (rf == rt &&
2250 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2251 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2252 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2253 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2254 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2255 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2257 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2259 /* This notation is always unambiguous, unless there are
2260 kings on both the d and e files, with "wild castling"
2261 possible for the king on the d file and normal castling
2262 possible for the other. ICS rules for wild 9
2263 effectively make castling illegal for either king in
2264 this situation. So I am not going to worry about it;
2265 I'll just generate an ambiguous O-O in this case.
2267 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2270 /* else fall through */
2275 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2276 cl.ft = fFilter = ft;
2278 cl.kind = IllegalMove;
2279 cl.rank = cl.file = cl.either = 0;
2280 c = PieceToChar(piece) ;
2281 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece)); // [HGM] speed
2283 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2284 /* Generate pretty moves for moving into check, but
2285 still return IllegalMove.
2287 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED piece));
2288 if (cl.kind == IllegalMove) break;
2289 cl.kind = IllegalMove;
2292 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2293 else "Ngf3" or "Ngxf7",
2294 else "N1f3" or "N5xf7",
2295 else "Ng1f3" or "Ng5xf7".
2297 if( c == '~' || c == '+') {
2298 /* [HGM] print nonexistent piece as its demoted version */
2299 piece = (ChessSquare) (DEMOTED piece - 11*(gameInfo.variant == VariantChu));
2301 if(c=='+') *outp++ = c;
2302 *outp++ = ToUpper(PieceToChar(piece));
2304 if (cl.file || (cl.either && !cl.rank)) {
2310 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2313 if(board[rt][ft] != EmptySquare)
2319 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2320 if (IS_SHOGI(gameInfo.variant)) {
2321 /* [HGM] in Shogi non-pawns can promote */
2322 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2324 else if (gameInfo.variant == VariantChuChess && promoChar ||
2325 gameInfo.variant != VariantSuper && promoChar &&
2326 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2328 *outp++ = ToUpper(promoChar);
2330 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2332 *outp++ = ToUpper(promoChar);
2338 /* Moving a nonexistent piece */
2342 /* Not a legal move, even ignoring check.
2343 If there was a piece on the from square,
2344 use style "Ng1g3" or "Ng1xe8";
2345 if there was a pawn or nothing (!),
2346 use style "g1g3" or "g1xe8". Use "x"
2347 if a piece was on the to square, even
2348 a piece of the same color.
2352 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2354 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2355 c += (board[r][f] == piece); // count on-board pieces of given type
2356 *outp++ = ToUpper(PieceToChar(piece));
2358 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2362 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2364 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2368 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2369 /* Use promotion suffix style "=Q" */
2370 if (promoChar != NULLCHAR && promoChar != 'x') {
2372 *outp++ = ToUpper(promoChar);
2379 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2388 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2390 int preyStackPointer, chaseStackPointer;
2393 unsigned char rf, ff, rt, ft;
2397 unsigned char rank, file;
2403 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2405 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2406 int rf, int ff, int rt, int ft,
2410 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2411 { // For adding captures that can lead to chase indictment to the chaseStack
2412 if(board[rt][ft] == EmptySquare) return; // non-capture
2413 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2414 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2415 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2416 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2417 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2418 chaseStack[chaseStackPointer].rf = rf;
2419 chaseStack[chaseStackPointer].ff = ff;
2420 chaseStack[chaseStackPointer].rt = rt;
2421 chaseStack[chaseStackPointer].ft = ft;
2422 chaseStackPointer++;
2425 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2426 int rf, int ff, int rt, int ft,
2430 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2431 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2433 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2435 if(board[rt][ft] == EmptySquare) return; // no capture
2436 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2437 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2439 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2440 for(i=0; i<chaseStackPointer; i++) {
2441 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2442 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2443 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2444 chaseStack[i] = chaseStack[--chaseStackPointer];
2450 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2451 int rf, int ff, int rt, int ft,
2455 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2456 { // for determining if a piece (given through the closure) is protected
2457 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2459 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2460 if(appData.debugMode && board[rt][ft] != EmptySquare)
2461 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2464 extern char moveList[MAX_MOVES][MOVE_LEN];
2467 PerpetualChase (int first, int last)
2468 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2471 ChessSquare captured;
2473 preyStackPointer = 0; // clear stack of chased pieces
2474 for(i=first; i<last; i+=2) { // for all positions with same side to move
2475 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2476 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2477 // determine all captures possible after the move, and put them on chaseStack
2478 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2479 if(appData.debugMode) { int n;
2480 for(n=0; n<chaseStackPointer; n++)
2481 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2482 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2483 fprintf(debugFP, ": all capts\n");
2485 // determine all captures possible before the move, and delete them from chaseStack
2486 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2487 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2488 cl.rt = moveList[i][3]-ONE;
2489 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2490 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2491 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2492 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2493 if(appData.debugMode) { int n;
2494 for(n=0; n<chaseStackPointer; n++)
2495 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2496 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2497 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2499 // chaseSack now contains all captures made possible by the move
2500 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2501 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2502 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2504 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2505 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2507 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2508 continue; // C or H attack on R is always chase; leave on chaseStack
2510 if(attacker == victim) {
2511 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2512 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2513 // we can capture back with equal piece, so this is no chase but a sacrifice
2514 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2515 j--; /* ! */ continue;
2520 // the attack is on a lower piece, or on a pinned or blocked equal one
2521 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2522 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2523 // test if the victim is protected by a true protector. First make the capture.
2524 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2525 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2526 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2527 // Then test if the opponent can recapture
2528 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2529 cl.rt = chaseStack[j].rt;
2530 cl.ft = chaseStack[j].ft;
2531 if(appData.debugMode) {
2532 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2534 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2535 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2536 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2537 // unmake the capture
2538 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2539 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2540 // if a recapture was found, piece is protected, and we are not chasing it.
2541 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2542 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2546 // chaseStack now contains all moves that chased
2547 if(appData.debugMode) { int n;
2548 for(n=0; n<chaseStackPointer; n++)
2549 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2550 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2551 fprintf(debugFP, ": chases\n");
2553 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2554 for(j=0; j<chaseStackPointer; j++) {
2555 preyStack[j].rank = chaseStack[j].rt;
2556 preyStack[j].file = chaseStack[j].ft;
2558 preyStackPointer = chaseStackPointer;
2561 for(j=0; j<chaseStackPointer; j++) {
2562 for(k=0; k<preyStackPointer; k++) {
2563 // search the victim of each chase move on the preyStack (first occurrence)
2564 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2565 if(k < tail) break; // piece was already identified as still being chased
2566 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2567 preyStack[tail] = preyStack[k]; // by swapping
2568 preyStack[k] = preyStack[preyStackPointer];
2574 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2575 if(appData.debugMode) { int n;
2576 for(n=0; n<preyStackPointer; n++)
2577 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2578 fprintf(debugFP, "always chased upto ply %d\n", i);
2580 // now adjust the location of the chased pieces according to opponent move
2581 for(j=0; j<preyStackPointer; j++) {
2582 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2583 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2584 preyStack[j].rank = moveList[i+1][3]-ONE;
2585 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2590 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2591 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the