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, 2015, 2016 Free
9 * Software Foundation, Inc.
11 * Enhancements Copyright 2005 Alessandro Scotti
13 * The following terms apply to Digital Equipment Corporation's copyright
15 * ------------------------------------------------------------------------
18 * Permission to use, copy, modify, and distribute this software and its
19 * documentation for any purpose and without fee is hereby granted,
20 * provided that the above copyright notice appear in all copies and that
21 * both that copyright notice and this permission notice appear in
22 * supporting documentation, and that the name of Digital not be
23 * used in advertising or publicity pertaining to distribution of the
24 * software without specific, written prior permission.
26 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
27 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
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29 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
30 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
31 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
33 * ------------------------------------------------------------------------
35 * The following terms apply to the enhanced version of XBoard
36 * distributed by the Free Software Foundation:
37 * ------------------------------------------------------------------------
39 * GNU XBoard is free software: you can redistribute it and/or modify
40 * it under the terms of the GNU General Public License as published by
41 * the Free Software Foundation, either version 3 of the License, or (at
42 * your option) any later version.
44 * GNU XBoard is distributed in the hope that it will be useful, but
45 * WITHOUT ANY WARRANTY; without even the implied warranty of
46 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
47 * General Public License for more details.
49 * You should have received a copy of the GNU General Public License
50 * along with this program. If not, see http://www.gnu.org/licenses/. *
52 *------------------------------------------------------------------------
53 ** See the file ChangeLog for a revision history. */
62 #else /* not HAVE_STRING_H */
64 #endif /* not HAVE_STRING_H */
70 int WhitePiece P((ChessSquare));
71 int BlackPiece P((ChessSquare));
72 int SameColor P((ChessSquare, ChessSquare));
73 int PosFlags(int index);
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 unsigned char pieceToChar[EmptySquare+1] = {
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 unsigned char pieceNickName[EmptySquare];
124 int promoPartner[EmptySquare];
127 PieceToChar (ChessSquare p)
130 if((int)p < 0 || (int)p >= (int)EmptySquare) return('?'); /* [HGM] for safety */
131 c = pieceToChar[(int) p];
132 if(c & 128) c = c & 63 | 64;
137 PieceSuffix (ChessSquare p)
140 if((int)p < 0 || (int)p >= (int)EmptySquare) return 0; /* [HGM] for safety */
141 c = pieceToChar[(int) p];
142 if(c < 128) return 0;
143 return SUFFIXES[c - 128 >> 6];
147 PieceToNumber (ChessSquare p) /* [HGM] holdings: count piece type, ignoring non-participating piece types */
150 ChessSquare start = (int)p >= (int)BlackPawn ? BlackPawn : WhitePawn;
152 while(start++ != p) if(pieceToChar[start-1] != '.' && pieceToChar[start-1] != '+') i++;
160 if(c == '.') return EmptySquare;
161 for(i=0; i< (int) EmptySquare; i++)
162 if(pieceNickName[i] == c) return (ChessSquare) i;
163 for(i=0; i< (int) EmptySquare; i++)
164 if(pieceToChar[i] == c) return (ChessSquare) i;
169 CopyBoard (Board to, Board from)
173 for (i = 0; i < BOARD_HEIGHT; i++)
174 for (j = 0; j < BOARD_WIDTH; j++)
175 to[i][j] = from[i][j];
176 for (j = 0; j < BOARD_FILES; j++) // [HGM] gamestate: copy castling rights and ep status
177 to[VIRGIN][j] = from[VIRGIN][j],
178 to[CASTLING][j] = from[CASTLING][j];
179 to[HOLDINGS_SET] = 0; // flag used in ICS play
183 CompareBoards (Board board1, Board board2)
187 for (i = 0; i < BOARD_HEIGHT; i++)
188 for (j = 0; j < BOARD_WIDTH; j++) {
189 if (board1[i][j] != board2[i][j])
195 char defaultName[] = "PNBRQ......................................K" // white
196 "pnbrq......................................k"; // black
197 char shogiName[] = "PNBRLS...G.++++++..........................K" // white
198 "pnbrls...g.++++++..........................k"; // black
199 char xqName[] = "PH.R.AE..K.C................................" // white
200 "ph.r.ae..k.c................................"; // black
203 CollectPieceDescriptors ()
204 { // make a line of piece descriptions for use in the PGN Piece tag:
205 // dump all engine defined pieces, and pieces with non-standard names,
206 // but suppress black pieces that are the same as their white counterpart
208 static char buf[MSG_SIZ], s[2];
209 char *m, c, d, *pieceName = defaultName;
212 if(!pieceDefs) return "";
213 if(gameInfo.variant == VariantChu) return ""; // for now don't do this for Chu Shogi
214 if(gameInfo.variant == VariantShogi) pieceName = shogiName;
215 if(gameInfo.variant == VariantXiangqi) pieceName = xqName;
216 for(p=WhitePawn; p<EmptySquare; p++) {
217 if((c = pieceToChar[p]) == '.' || c == '~') continue; // does not participate
218 m = pieceDesc[p]; d = (c == '+' ? pieceToChar[DEMOTED(p)] : c);
219 if(p >= BlackPawn && pieceToChar[BLACK_TO_WHITE p] == (c & ~32)
220 && (c != '+' || pieceToChar[DEMOTED(BLACK_TO_WHITE p)] == d)) {// black member of normal pair
221 char *wm = pieceDesc[BLACK_TO_WHITE p];
222 if(!m && !wm || m && wm && !strcmp(wm, m)) continue; // moves as a white piece
223 } else // white or unpaired black
224 if((p < BlackPawn || CharToPiece(d & ~32) != EmptySquare) && // white or lone black
225 !pieceDesc[p] /*&& pieceName[p] == c*/) continue; // orthodox piece known by its usual name
226 // TODO: listing pieces because of unusual name can only be done if we have accurate Betza of all defaults
227 if(!m) m = defaultDesc[p];
230 *s = (d > 128 ? SUFFIXES[d-128>>6] : 0); d = 64 + (d & 63);
231 snprintf(buf+len, MSG_SIZ-len, "%s%s%c%s:%s", len ? ";" : "", c == '+' ? "+" : "", d, s, m);
237 LoadPieceDesc (char *s)
240 static char suf[] = SUFFIXES;
242 int ok = TRUE, promoted, c;
246 if(q) *q = 0, s = q+1;
247 if(*p == '+') promoted = 1, p++; else promoted = 0;
249 if(!c) { ok = FALSE; continue; } // bad syntax
250 if(*p && (r = strchr(suf, *p))) c += 64*(r - suf + 1), p++;
251 if(*p++ != ':') { ok = FALSE; continue; } // bad syntax
252 if(!strcmp(p, "(null)")) continue; // handle bug in writing of XBoard 4.8.0
253 piece = CharToPiece(c);
254 if(piece >= EmptySquare) { ok = FALSE; continue; } // non-existent piece
256 piece = promoPartner[piece];
257 if(pieceToChar[piece] != '+') { ok = FALSE; continue; } // promoted form does not exist
259 ASSIGN(pieceDesc[piece], p);
260 if(piece < BlackPawn && (pieceToChar[WHITE_TO_BLACK piece] == pieceToChar[piece] + 32 || promoted)) {
261 ASSIGN(pieceDesc[WHITE_TO_BLACK piece], p);
268 // [HGM] gen: configurable move generation from Betza notation sent by engine.
269 // Some notes about two-leg moves: GenPseudoLegal() works in two modes, depending on whether a 'kill-
270 // square has been set: without one is generates all moves, and a global int legNr flags in bits 0 and 1
271 // if the move has 1 or 2 legs. Only the marking of squares makes use of this info, by only marking
272 // target squares of leg 1 (rejecting null move). A dummy move with MoveType 'FirstLeg' to the relay square
273 // is generated, so a cyan marker can be put there, and other functions can ignore such a move. When the
274 // user selects this square, it becomes the kill-square. Once a kill-square is set, only 2-leg moves are
275 // generated that use that square as relay, plus 1-leg moves, so the 1-leg move that goes to the kill-square
276 // can be marked during 2nd-leg entry to terminate the move there. For judging the pseudo-legality of the
277 // 2nd leg, the from-square has to be considered empty, although the moving piece is still on it.
281 // alphabet "abcdefghijklmnopqrstuvwxyz"
282 char symmetry[] = "FBNW.FFW.NKN.NW.QR....W..N";
283 char xStep[] = "2110.130.102.10.00....0..2";
284 char yStep[] = "2132.133.313.20.11....1..3";
285 char dirType[] = "01000104000200000260050000";
286 char upgrade[] = "AFCD.BGH.JQL.NO.KW....R..Z";
287 char rotate[] = "DRCA.WHG.JKL.NO.QB....F..Z";
289 // 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 "
290 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 };
291 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 };
292 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 };
293 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 };
295 int rot[][4] = { // rotation matrices for each direction
307 OK (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR cl)
313 MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle, char *desc, MoveCallback cb, VOIDSTAR cl)
315 char buf[80], *p = desc, *atom = NULL;
316 int mine, his, dir, bit, occup, i, ep, promoRank = -1;
317 ChessMove promo= NormalMove; ChessSquare pc = board[r][f];
318 if(pc == DarkSquare) return; // this is not a piece, but a 'hole' in the board
319 if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
320 if(pc == WhitePawn || pc == WhiteLance) promo = WhitePromotion, promoRank = BOARD_HEIGHT-1; else
321 if(pc == BlackPawn || pc == BlackLance) promo = BlackPromotion, promoRank = 0;
322 while(*p) { // more moves to go
323 int expo = -1, dx, dy, x, y, mode, dirSet, ds2=0, retry=0, initial=0, jump=1, skip = 0, all = 0;
325 while(*p == 'i') initial++, desc = ++p;
326 while(islower(*p)) p++; // skip prefixes
327 if(!isupper(*p)) return; // syntax error: no atom
328 dx = xStep[*p-'A'] - '0';// step vector of atom
329 dy = yStep[*p-'A'] - '0';
330 dirSet = 0; // build direction set based on atom symmetry
331 switch(symmetry[*p-'A']) {
332 case 'B': expo = 0; // bishop, slide
333 case 'F': all = 0xAA; // diagonal atom (degenerate 4-fold)
334 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
335 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
336 int b = dirs1[*desc-'a']; // use wide version
337 if( islower(desc[1]) &&
338 ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim)
339 b = dirs1[*desc-'a'] & dirs1[desc[1]-'a']; // intersect wide & perp wide
344 dirSet &= 0xAA; if(!dirSet) dirSet = 0xAA;
346 case 'R': expo = 0; // rook, slide
347 case 'W': all = 0x55; // orthogonal atom (non-deg 4-fold)
348 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
349 while(islower(*desc) && (dirType[*desc-'a'] & ~4) != '0') dirSet |= dirs2[*desc++-'a'];
350 dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
351 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
353 case 'N': all = 0xFF; // oblique atom (degenerate 8-fold)
354 if(tx >= 0) goto king; // continuation legs specified in K/Q system!
355 if(*desc == 'h') { // chiral direction sets 'hr' and 'hl'
356 dirSet = (desc[1] == 'r' ? 0x55 : 0xAA); desc += 2;
358 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
359 int b = dirs2[*desc-'a']; // when alone, use narrow version
360 if(desc[1] == 'h') b = dirs1[*desc-'a'], desc += 2; // dirs1 is wide version
361 else if(*desc == desc[1] || islower(desc[1]) && i < '4'
362 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
363 b = dirs1[*desc-'a'] & dirs2[desc[1]-'a']; // intersect wide & perp narrow
368 if(!dirSet) dirSet = 0xFF;
370 case 'Q': expo = 0; // queen, slide
371 case 'K': all = 0xFF; // non-deg (pseudo) 8-fold
373 while(islower(*desc) && (i = dirType[*desc-'a']) != '0') {
374 int b = dirs4[*desc-'a']; // when alone, use narrow version
375 if(desc[1] == *desc) desc++; // doubling forces alone
376 else if(islower(desc[1]) && i < '4'
377 && ((i | dirType[desc[1]-'a']) & 3) == 3) { // combinable (perpendicular dim or same)
378 b = dirs3[*desc-'a'] & dirs3[desc[1]-'a']; // intersect wide & perp wide
383 if(!dirSet) dirSet = (tx < 0 ? 0xFF // default is all directions, but in continuation leg
384 : all == 0xFF ? 0xEF : 0x45); // omits backward, and for 4-fold atoms also diags
385 dirSet = (dirSet << angle | dirSet >> 8-angle) & 255; // re-orient direction system
386 ds2 = dirSet & 0xAA; // extract diagonal directions
387 if(dirSet &= 0x55) // start with orthogonal moves, if present
388 retry = 1, dx = 0; // and schedule the diagonal moves for later
389 else dx = dy, dirSet = ds2; // if no orthogonal directions, do diagonal immediately
390 break; // should not have direction indicators
391 default: return; // syntax error: invalid atom
393 if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255; // invert black moves
394 mode = 0; // build mode mask
395 if(*desc == 'm') mode |= 4, desc++; // move to empty
396 if(*desc == 'c') mode |= his, desc++; // capture foe
397 if(*desc == 'd') mode |= mine, desc++; // destroy (capture friend)
398 if(*desc == 'e') mode |= 8, desc++; // e.p. capture last mover
399 if(*desc == 't') mode |= 16, desc++; // exclude enemies as hop platform ('test')
400 if(*desc == 'p') mode |= 32, desc++; // hop over occupied
401 if(*desc == 'g') mode |= 64, desc++; // hop and toggle range
402 if(*desc == 'o') mode |= 128, desc++; // wrap around cylinder board
403 if(*desc == 'y') mode |= 512, desc++; // toggle range on empty square
404 if(*desc == 'n') jump = 0, desc++; // non-jumping
405 while(*desc == 'j') jump++, desc++; // must jump (on B,R,Q: skip first square)
406 if(*desc == 'a') cont = ++desc; // move again after doing what preceded it
407 if(isdigit(*++p)) expo = atoi(p++); // read exponent
408 if(expo > 9) p++; // allow double-digit
409 desc = p; // this is start of next move
410 if(initial == 2) { if(board[r][f] != initialPosition[r-2*his+3][f]) continue; } else
411 if(initial && (board[r][f] != initialPosition[r][f] ||
412 r == 0 && board[TOUCHED_W] & 1<<f ||
413 r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f ) ) continue;
414 if(expo > 0 && dx == 0 && dy == 0) { // castling indicated by O + number
415 mode |= 1024; dy = 1;
417 if(expo < 0) expo = 1; // use 1 for default
419 if(!(mode & 15)) mode |= his + 4; // no mode spec, use default = mc
421 strncpy(buf, cont, 80); cont = buf; // copy next leg(s), so we can modify
422 atom = buf; while(islower(*atom)) atom++; // skip to atom
423 if(mode & 32) mode ^= 256 + 32; // in non-final legs 'p' means 'pass through'
424 if(mode & 64 + 512) {
425 mode |= 256; // and 'g' too, but converts leaper <-> slider
426 if(mode & 512) mode ^= 0x304; // and 'y' is m-like 'g'
427 *atom = upgrade[*atom-'A']; // replace atom, BRQ <-> FWK
428 atom[1] = atom[2] = '\0'; // make sure any old range is stripped off
429 if(expo == 1) atom[1] = '0'; // turn other leapers into riders
431 if(!(mode & 0x30F)) mode |= 4; // and default of this leg = m
433 if(dy == 1) skip = jump - 1, jump = 1; // on W & F atoms 'j' = skip first square
435 for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
436 int i = expo, j = skip, hop = mode, vx, vy, loop = 0;
437 if(!(bit & dirSet)) continue; // does not move in this direction
438 if(dy != 1 || mode & 1024) j = 0; //
439 vx = dx*rot[dir][0] + dy*rot[dir][1]; // rotate step vector
440 vy = dx*rot[dir][2] + dy*rot[dir][3];
441 if(tx < 0) x = f, y = r; // start square
442 else x = tx, y = ty; // from previous to-square if continuation
444 x += vx; y += vy; // step to next square
445 if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
446 if(x < BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT, loop++; else break; }
447 if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT, loop++; else break; }
448 if(j) { j--; continue; } // skip irrespective of occupation
449 if(board[y][x] == DarkSquare) break; // black squares are supposed to be off board
450 if(!jump && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
451 if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
452 if(x == f && y == r && !loop) occup = 4; else // start square counts as empty (if not around cylinder!)
453 if(board[y][x] < BlackPawn) occup = 0x101; else
454 if(board[y][x] < EmptySquare) occup = 0x102; else
456 if(cont) { // non-final leg
457 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
458 if(occup & mode) { // valid intermediate square, do continuation
459 char origAtom = *atom;
460 if(!(bit & all)) *atom = rotate[*atom - 'A']; // orth-diag interconversion to make direction valid
461 if(occup & mode & 0x104) // no side effects, merge legs to one move
462 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
463 if(occup & mode & 3 && (killX < 0 || killX == x && killY == y)) { // destructive first leg
465 MovesFromString(board, flags, f, r, x, y, dir, cont, &OK, &cnt); // count possible continuations
466 if(cnt) { // and if there are
467 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); // then generate their first leg
469 MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
473 *atom = origAtom; // undo any interconversion
475 if(occup != 4) break; // occupied squares always terminate the leg
478 if(hop & 32+64) { if(occup != 4) { if(hop & 64 && i != 1) i = 2; hop &= 31; } continue; } // hopper
480 if(mode & 8 && occup == 4 && board[EP_FILE] == x && (y == (ep & 127) || y - vy == ep - 128)) { // to e.p. square (or 2nd e.p. square)
481 cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
483 if(mode & 1024) { // castling
484 i = 2; // kludge to elongate move indefinitely
485 if(occup == 4) continue; // skip empty squares
486 if((x == BOARD_LEFT + skip || x > BOARD_LEFT + skip && vx < 0 && board[y][x-1-skip] == DarkSquare)
487 && board[y][x] == initialPosition[y][x]) { // reached initial corner piece
488 if(pc != WhiteKing && pc != BlackKing || expo == 1) { // non-royal castling (to be entered as two-leg move via 'Rook')
489 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); if(killX < f)
490 legNr <<= 1, cb(board, flags, NormalMove, r, f, y, f - expo, cl), legNr >>= 1;
492 cb(board, flags, mine == 1 ? WhiteQueenSideCastle : BlackQueenSideCastle, r, f, y, f - expo, cl);
494 if((x == BOARD_RGHT-1-skip || x < BOARD_RGHT-1-skip && vx > 0 && board[y][x+1+skip] == DarkSquare)
495 && board[y][x] == initialPosition[y][x]) {
496 if(pc != WhiteKing && pc != BlackKing || expo == 1) {
497 if(killX < 0) cb(board, flags, FirstLeg, r, f, y, x, cl); if(killX > f)
498 legNr <<= 1, cb(board, flags, NormalMove, r, f, y, f + expo, cl), legNr >>= 1;
500 cb(board, flags, mine == 1 ? WhiteKingSideCastle : BlackKingSideCastle, r, f, y, f + expo, cl);
504 if(mode & 16 && (board[y][x] == WhiteKing || board[y][x] == BlackKing)) break; // tame piece, cannot capture royal
505 if(occup & mode) cb(board, flags, y == promoRank ? promo : NormalMove, r, f, y, x, cl); // allowed, generate
506 if(occup != 4) break; // not valid transit square
509 dx = dy; dirSet = ds2; // prepare for diagonal moves of K,Q
510 } while(retry-- && ds2); // and start doing them
511 if(tx >= 0) break; // don't do other atoms in continuation legs
515 // [HGM] move generation now based on hierarchy of subroutines for rays and combinations of rays
518 SlideForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
523 if (rt >= BOARD_HEIGHT) break;
524 if (SameColor(board[rf][ff], board[rt][ft])) break;
525 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
526 if (board[rt][ft] != EmptySquare) break;
531 SlideBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
537 if (SameColor(board[rf][ff], board[rt][ft])) break;
538 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
539 if (board[rt][ft] != EmptySquare) break;
544 SlideVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
546 SlideForward(board, flags, rf, ff, callback, closure);
547 SlideBackward(board, flags, rf, ff, callback, closure);
551 SlideSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
553 int i, s, rt = rf, ft;
554 for(s = -1; s <= 1; s+= 2) {
557 if (ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
558 if (SameColor(board[rf][ff], board[rt][ft])) break;
559 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
560 if (board[rt][ft] != EmptySquare) break;
566 SlideDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
569 for(s = -1; s <= 1; s+= 2) {
573 if (rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
574 if (SameColor(board[rf][ff], board[rt][ft])) break;
575 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
576 if (board[rt][ft] != EmptySquare) break;
582 SlideDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
585 for(s = -1; s <= 1; s+= 2) {
589 if (rt < 0 || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
590 if (SameColor(board[rf][ff], board[rt][ft])) break;
591 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
592 if (board[rt][ft] != EmptySquare) break;
598 Rook (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
600 SlideVertical(board, flags, rf, ff, callback, closure);
601 SlideSideways(board, flags, rf, ff, callback, closure);
605 Bishop (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
607 SlideDiagForward(board, flags, rf, ff, callback, closure);
608 SlideDiagBackward(board, flags, rf, ff, callback, closure);
612 Sting (Board board, int flags, int rf, int ff, int dy, int dx, MoveCallback callback, VOIDSTAR closure)
613 { // Lion-like move of Horned Falcon and Souring Eagle
614 int ft = ff + dx, rt = rf + dy;
615 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
617 if (!SameColor(board[rf][ff], board[rt][ft]))
618 callback(board, flags, board[rt][ft] != EmptySquare ? FirstLeg : NormalMove, rf, ff, rt, ft, closure);
621 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) return;
623 if (!SameColor(board[rf][ff], board[rt][ft]))
624 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
625 if (!SameColor(board[rf][ff], board[rf+dy][ff+dx]))
626 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
631 StepForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
633 int ft = ff, rt = rf + 1;
634 if (rt >= BOARD_HEIGHT) return;
635 if (SameColor(board[rf][ff], board[rt][ft])) return;
636 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
640 StepBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
642 int ft = ff, rt = rf - 1;
644 if (SameColor(board[rf][ff], board[rt][ft])) return;
645 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
649 StepSideways (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
653 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
654 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
656 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
657 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
661 StepDiagForward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
664 if (rt >= BOARD_HEIGHT) return;
666 if (!(rt >= BOARD_HEIGHT || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
667 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
669 if (!(rt >= BOARD_HEIGHT || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
670 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
674 StepDiagBackward (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
679 if (!(rt < 0 || ft >= BOARD_RGHT) && !SameColor(board[rf][ff], board[rt][ft]))
680 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
682 if (!(rt < 0 || ft < BOARD_LEFT) && !SameColor(board[rf][ff], board[rt][ft]))
683 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
687 StepVertical (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
689 StepForward(board, flags, rf, ff, callback, closure);
690 StepBackward(board, flags, rf, ff, callback, closure);
694 Ferz (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
696 StepDiagForward(board, flags, rf, ff, callback, closure);
697 StepDiagBackward(board, flags, rf, ff, callback, closure);
701 Wazir (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
703 StepVertical(board, flags, rf, ff, callback, closure);
704 StepSideways(board, flags, rf, ff, callback, closure);
708 Knight (Board board, int flags, int rf, int ff, MoveCallback callback, VOIDSTAR closure)
711 for (i = -1; i <= 1; i += 2)
712 for (j = -1; j <= 1; j += 2)
713 for (s = 1; s <= 2; s++) {
716 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
717 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
718 && !SameColor(board[rf][ff], board[rt][ft]))
719 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
723 /* Call callback once for each pseudo-legal move in the given
724 position, except castling moves. A move is pseudo-legal if it is
725 legal, or if it would be legal except that it leaves the king in
726 check. In the arguments, epfile is EP_NONE if the previous move
727 was not a double pawn push, or the file 0..7 if it was, or
728 EP_UNKNOWN if we don't know and want to allow all e.p. captures.
729 Promotion moves generated are to Queen only.
732 GenPseudoLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
733 // speed: only do moves with this piece type
736 int i, j, d, s, fs, rs, rt, ft, m;
737 int epfile = (signed char)board[EP_STATUS]; // [HGM] gamestate: extract ep status from board
738 int promoRank = gameInfo.variant == VariantMakruk || gameInfo.variant == VariantGrand || gameInfo.variant == VariantChuChess ? 3 : 1;
740 for (rf = 0; rf < BOARD_HEIGHT; rf++)
741 for (ff = BOARD_LEFT; ff < BOARD_RGHT; ff++) {
744 if(board[rf][ff] == EmptySquare) continue;
745 if ((flags & F_WHITE_ON_MOVE) != (board[rf][ff] < BlackPawn)) continue; // [HGM] speed: wrong color
746 m = 0; piece = board[rf][ff];
747 if(PieceToChar(piece) == '~')
748 piece = (ChessSquare) ( DEMOTED(piece) );
749 if(filter != EmptySquare && piece != filter) continue;
750 if(pieceDefs && pieceDesc[piece]) { // [HGM] gen: use engine-defined moves
751 MovesFromString(board, flags, ff, rf, -1, -1, 0, pieceDesc[piece], callback, closure);
754 if(IS_SHOGI(gameInfo.variant))
755 piece = (ChessSquare) ( SHOGI piece );
757 switch ((int)piece) {
758 /* case EmptySquare: [HGM] this is nonsense, and conflicts with Shogi cases */
760 /* can't happen ([HGM] except for faries...) */
764 if(gameInfo.variant == VariantXiangqi) {
765 /* [HGM] capture and move straight ahead in Xiangqi */
766 if (rf < BOARD_HEIGHT-1 &&
767 !SameColor(board[rf][ff], board[rf + 1][ff]) ) {
768 callback(board, flags, NormalMove,
769 rf, ff, rf + 1, ff, closure);
771 /* and move sideways when across the river */
772 for (s = -1; s <= 1; s += 2) {
773 if (rf >= BOARD_HEIGHT>>1 &&
774 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
775 !WhitePiece(board[rf][ff+s]) ) {
776 callback(board, flags, NormalMove,
777 rf, ff, rf, ff+s, closure);
782 if (rf < BOARD_HEIGHT-1 && board[rf + 1][ff] == EmptySquare) {
783 callback(board, flags,
784 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
785 rf, ff, rf + 1, ff, closure);
787 if (rf <= (BOARD_HEIGHT>>1)-3 && board[rf+1][ff] == EmptySquare && // [HGM] grand: also on 3rd rank on 10-board
788 gameInfo.variant != VariantShatranj && /* [HGM] */
789 gameInfo.variant != VariantCourier && /* [HGM] */
790 board[rf+2][ff] == EmptySquare ) {
791 callback(board, flags, NormalMove,
792 rf, ff, rf+2, ff, closure);
794 for (s = -1; s <= 1; s += 2) {
795 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
796 ((flags & F_KRIEGSPIEL_CAPTURE) ||
797 BlackPiece(board[rf + 1][ff + s]))) {
798 callback(board, flags,
799 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
800 rf, ff, rf + 1, ff + s, closure);
802 if (rf >= BOARD_HEIGHT+1>>1) {// [HGM] grand: 4th & 5th rank on 10-board
803 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
804 (epfile == ff + s || epfile == EP_UNKNOWN) && rf < BOARD_HEIGHT-3 &&
805 board[rf][ff + s] == BlackPawn &&
806 board[rf+1][ff + s] == EmptySquare) {
807 callback(board, flags, WhiteCapturesEnPassant,
808 rf, ff, rf+1, ff + s, closure);
815 if(gameInfo.variant == VariantXiangqi) {
816 /* [HGM] capture straight ahead in Xiangqi */
817 if (rf > 0 && !SameColor(board[rf][ff], board[rf - 1][ff]) ) {
818 callback(board, flags, NormalMove,
819 rf, ff, rf - 1, ff, closure);
821 /* and move sideways when across the river */
822 for (s = -1; s <= 1; s += 2) {
823 if (rf < BOARD_HEIGHT>>1 &&
824 ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
825 !BlackPiece(board[rf][ff+s]) ) {
826 callback(board, flags, NormalMove,
827 rf, ff, rf, ff+s, closure);
832 if (rf > 0 && board[rf - 1][ff] == EmptySquare) {
833 callback(board, flags,
834 rf <= promoRank ? BlackPromotion : NormalMove,
835 rf, ff, rf - 1, ff, closure);
837 if (rf >= (BOARD_HEIGHT+1>>1)+2 && board[rf-1][ff] == EmptySquare && // [HGM] grand
838 gameInfo.variant != VariantShatranj && /* [HGM] */
839 gameInfo.variant != VariantCourier && /* [HGM] */
840 board[rf-2][ff] == EmptySquare) {
841 callback(board, flags, NormalMove,
842 rf, ff, rf-2, ff, closure);
844 for (s = -1; s <= 1; s += 2) {
845 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
846 ((flags & F_KRIEGSPIEL_CAPTURE) ||
847 WhitePiece(board[rf - 1][ff + s]))) {
848 callback(board, flags,
849 rf <= promoRank ? BlackPromotion : NormalMove,
850 rf, ff, rf - 1, ff + s, closure);
852 if (rf < BOARD_HEIGHT>>1) {
853 if (ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
854 (epfile == ff + s || epfile == EP_UNKNOWN) && rf > 2 &&
855 board[rf][ff + s] == WhitePawn &&
856 board[rf-1][ff + s] == EmptySquare) {
857 callback(board, flags, BlackCapturesEnPassant,
858 rf, ff, rf-1, ff + s, closure);
868 for (i = -1; i <= 1; i += 2)
869 for (j = -1; j <= 1; j += 2)
870 for (s = 1; s <= 2; s++) {
873 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
874 && ( gameInfo.variant != VariantXiangqi || board[rf+i*(s-1)][ff+j*(2-s)] == EmptySquare)
875 && !SameColor(board[rf][ff], board[rt][ft]))
876 callback(board, flags, NormalMove,
877 rf, ff, rt, ft, closure);
881 case SHOGI WhiteKnight:
882 for (s = -1; s <= 1; s += 2) {
883 if (rf < BOARD_HEIGHT-2 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
884 !SameColor(board[rf][ff], board[rf + 2][ff + s])) {
885 callback(board, flags, NormalMove,
886 rf, ff, rf + 2, ff + s, closure);
891 case SHOGI BlackKnight:
892 for (s = -1; s <= 1; s += 2) {
893 if (rf > 1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT &&
894 !SameColor(board[rf][ff], board[rf - 2][ff + s])) {
895 callback(board, flags, NormalMove,
896 rf, ff, rf - 2, ff + s, closure);
903 for (d = 0; d <= 1; d++)
904 for (s = -1; s <= 1; s += 2) {
907 rt = rf + (i * s) * d;
908 ft = ff + (i * s) * (1 - d);
909 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
910 if (m == 0 && board[rt][ft] == EmptySquare)
911 callback(board, flags, NormalMove,
912 rf, ff, rt, ft, closure);
913 if (m == 1 && board[rt][ft] != EmptySquare &&
914 !SameColor(board[rf][ff], board[rt][ft]) )
915 callback(board, flags, NormalMove,
916 rf, ff, rt, ft, closure);
917 if (board[rt][ft] != EmptySquare && m++) break;
922 /* Gold General (and all its promoted versions) . First do the */
923 /* diagonal forward steps, then proceed as normal Wazir */
924 case SHOGI (PROMO WhitePawn):
925 if(gameInfo.variant == VariantShogi) goto WhiteGold;
926 case SHOGI (PROMO BlackPawn):
927 if(gameInfo.variant == VariantShogi) goto BlackGold;
928 SlideVertical(board, flags, rf, ff, callback, closure);
931 case SHOGI (PROMO WhiteKnight):
932 if(gameInfo.variant == VariantShogi) goto WhiteGold;
933 case SHOGI BlackDrunk:
934 case SHOGI BlackAlfil:
935 Ferz(board, flags, rf, ff, callback, closure);
936 StepSideways(board, flags, rf, ff, callback, closure);
937 StepBackward(board, flags, rf, ff, callback, closure);
940 case SHOGI (PROMO BlackKnight):
941 if(gameInfo.variant == VariantShogi) goto BlackGold;
942 case SHOGI WhiteDrunk:
943 case SHOGI WhiteAlfil:
944 Ferz(board, flags, rf, ff, callback, closure);
945 StepSideways(board, flags, rf, ff, callback, closure);
946 StepForward(board, flags, rf, ff, callback, closure);
952 if(gameInfo.variant == VariantShogi) goto BlackGold;
953 SlideVertical(board, flags, rf, ff, callback, closure);
954 Ferz(board, flags, rf, ff, callback, closure);
955 StepSideways(board, flags, rf, ff, callback, closure);
958 case SHOGI (PROMO WhiteQueen):
959 case SHOGI WhiteTokin:
960 case SHOGI WhiteWazir:
962 StepDiagForward(board, flags, rf, ff, callback, closure);
963 Wazir(board, flags, rf, ff, callback, closure);
966 case SHOGI (PROMO BlackQueen):
967 case SHOGI BlackTokin:
968 case SHOGI BlackWazir:
970 StepDiagBackward(board, flags, rf, ff, callback, closure);
971 Wazir(board, flags, rf, ff, callback, closure);
976 Wazir(board, flags, rf, ff, callback, closure);
979 case SHOGI WhiteMarshall:
980 case SHOGI BlackMarshall:
981 Ferz(board, flags, rf, ff, callback, closure);
982 for (d = 0; d <= 1; d++)
983 for (s = -2; s <= 2; s += 4) {
985 ft = ff + s * (1 - d);
986 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
987 if (!SameColor(board[rf][ff], board[rt][ft]) )
988 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
992 case SHOGI WhiteAngel:
993 case SHOGI BlackAngel:
994 Wazir(board, flags, rf, ff, callback, closure);
998 /* [HGM] support Shatranj pieces */
999 for (rs = -1; rs <= 1; rs += 2)
1000 for (fs = -1; fs <= 1; fs += 2) {
1003 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
1004 && ( gameInfo.variant != VariantXiangqi ||
1005 board[rf+rs][ff+fs] == EmptySquare && (2*rf < BOARD_HEIGHT) == (2*rt < BOARD_HEIGHT) )
1007 && !SameColor(board[rf][ff], board[rt][ft]))
1008 callback(board, flags, NormalMove,
1009 rf, ff, rt, ft, closure);
1010 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
1011 gameInfo.variant == VariantChu || gameInfo.variant == VariantXiangqi) continue; // classical Alfil
1012 rt = rf + rs; // in unknown variant we assume Modern Elephant, which can also do one step
1014 if (!(rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT)
1015 && !SameColor(board[rf][ff], board[rt][ft]))
1016 callback(board, flags, NormalMove,
1017 rf, ff, rt, ft, closure);
1019 if(gameInfo.variant == VariantSpartan)
1020 for(fs = -1; fs <= 1; fs += 2) {
1022 if (!(ft < BOARD_LEFT || ft >= BOARD_RGHT) && board[rf][ft] == EmptySquare)
1023 callback(board, flags, NormalMove, rf, ff, rf, ft, closure);
1027 /* Make Dragon-Horse also do Dababba moves outside Shogi, for better disambiguation in variant Fairy */
1030 if(gameInfo.variant == VariantChuChess) goto DragonHorse;
1031 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1032 for (s = -2; s <= 2; s += 4) {
1034 ft = ff + s * (1 - d);
1035 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1036 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1037 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1040 /* Shogi Dragon Horse has to continue with Wazir after Bishop */
1041 case SHOGI WhiteCardinal:
1042 case SHOGI BlackCardinal:
1043 case SHOGI WhitePCardinal:
1044 case SHOGI BlackPCardinal:
1046 Bishop(board, flags, rf, ff, callback, closure);
1047 Wazir(board, flags, rf, ff, callback, closure);
1050 /* Capablanca Archbishop continues as Knight */
1053 Knight(board, flags, rf, ff, callback, closure);
1055 /* Shogi Bishops are ordinary Bishops */
1056 case SHOGI WhiteBishop:
1057 case SHOGI BlackBishop:
1058 case SHOGI WhitePBishop:
1059 case SHOGI BlackPBishop:
1062 Bishop(board, flags, rf, ff, callback, closure);
1065 /* Shogi Lance is unlike anything, and asymmetric at that */
1066 case SHOGI WhiteQueen:
1067 if(gameInfo.variant == VariantChu) goto doQueen;
1071 if (rt >= BOARD_HEIGHT) break;
1072 if (SameColor(board[rf][ff], board[rt][ft])) break;
1073 callback(board, flags, NormalMove,
1074 rf, ff, rt, ft, closure);
1075 if (board[rt][ft] != EmptySquare) break;
1079 case SHOGI BlackQueen:
1080 if(gameInfo.variant == VariantChu) goto doQueen;
1085 if (SameColor(board[rf][ff], board[rt][ft])) break;
1086 callback(board, flags, NormalMove,
1087 rf, ff, rt, ft, closure);
1088 if (board[rt][ft] != EmptySquare) break;
1092 /* Make Dragon-King Dababba & Rook-like outside Shogi, for better disambiguation in variant Fairy */
1095 if(gameInfo.variant == VariantChuChess) goto DragonKing;
1096 for (d = 0; d <= 1; d++) // Dababba moves that Rook cannot do
1097 for (s = -2; s <= 2; s += 4) {
1099 ft = ff + s * (1 - d);
1100 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1101 if (board[rf+rt>>1][ff+ft>>1] == EmptySquare && gameInfo.variant != VariantSpartan) continue;
1102 if (SameColor(board[rf][ff], board[rt][ft])) continue;
1103 callback(board, flags, NormalMove, rf, ff, rt, ft, closure);
1105 if(gameInfo.variant == VariantSpartan) // in Spartan Chess restrict range to modern Dababba
1106 Wazir(board, flags, rf, ff, callback, closure);
1108 Rook(board, flags, rf, ff, callback, closure);
1111 /* Shogi Dragon King has to continue as Ferz after Rook moves */
1112 case SHOGI WhiteDragon:
1113 case SHOGI BlackDragon:
1114 case SHOGI WhitePDragon:
1115 case SHOGI BlackPDragon:
1117 Rook(board, flags, rf, ff, callback, closure);
1118 Ferz(board, flags, rf, ff, callback, closure);
1122 /* Capablanca Chancellor sets flag to continue as Knight */
1125 Rook(board, flags, rf, ff, callback, closure);
1126 if(gameInfo.variant == VariantSpartan) // in Spartan Chess Chancellor is used for Dragon King.
1127 Ferz(board, flags, rf, ff, callback, closure);
1129 Knight(board, flags, rf, ff, callback, closure);
1132 /* Shogi Rooks are ordinary Rooks */
1133 case SHOGI WhiteRook:
1134 case SHOGI BlackRook:
1135 case SHOGI WhitePRook:
1136 case SHOGI BlackPRook:
1139 Rook(board, flags, rf, ff, callback, closure);
1144 case SHOGI WhiteMother:
1145 case SHOGI BlackMother:
1147 Rook(board, flags, rf, ff, callback, closure);
1148 Bishop(board, flags, rf, ff, callback, closure);
1151 case SHOGI WhitePawn:
1152 StepForward(board, flags, rf, ff, callback, closure);
1155 case SHOGI BlackPawn:
1156 StepBackward(board, flags, rf, ff, callback, closure);
1160 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1161 case SHOGI WhiteFerz:
1162 Ferz(board, flags, rf, ff, callback, closure);
1163 StepForward(board, flags, rf, ff, callback, closure);
1167 if(gameInfo.variant != VariantMakruk && gameInfo.variant != VariantASEAN) goto commoner;
1168 case SHOGI BlackFerz:
1169 StepBackward(board, flags, rf, ff, callback, closure);
1173 /* [HGM] support Shatranj pieces */
1174 Ferz(board, flags, rf, ff, callback, closure);
1179 Knight(board, flags, rf, ff, callback, closure); // [HGM] superchess: use for Centaur
1182 case SHOGI WhiteMonarch:
1183 case SHOGI BlackMonarch:
1184 case SHOGI WhiteKing:
1185 case SHOGI BlackKing:
1188 Ferz(board, flags, rf, ff, callback, closure);
1189 Wazir(board, flags, rf, ff, callback, closure);
1192 case WhiteNightrider:
1193 case BlackNightrider:
1194 for (i = -1; i <= 1; i += 2)
1195 for (j = -1; j <= 1; j += 2)
1196 for (s = 1; s <= 2; s++) { int k;
1199 ft = ff + k*j*(3-s);
1200 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) break;
1201 if (SameColor(board[rf][ff], board[rt][ft])) break;
1202 callback(board, flags, NormalMove,
1203 rf, ff, rt, ft, closure);
1204 if (board[rt][ft] != EmptySquare) break;
1210 Bishop(board, flags, rf, ff, callback, closure);
1211 Rook(board, flags, rf, ff, callback, closure);
1212 Knight(board, flags, rf, ff, callback, closure);
1215 // Use Lance as Berolina / Spartan Pawn.
1217 if(gameInfo.variant == VariantSuper) goto Amazon;
1218 if (rf < BOARD_HEIGHT-1 && BlackPiece(board[rf + 1][ff]))
1219 callback(board, flags,
1220 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1221 rf, ff, rf + 1, ff, closure);
1222 for (s = -1; s <= 1; s += 2) {
1223 if (rf < BOARD_HEIGHT-1 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf + 1][ff + s] == EmptySquare)
1224 callback(board, flags,
1225 rf >= BOARD_HEIGHT-1-promoRank ? WhitePromotion : NormalMove,
1226 rf, ff, rf + 1, ff + s, closure);
1227 if (rf == 1 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[3][ff + 2*s] == EmptySquare )
1228 callback(board, flags, NormalMove, rf, ff, 3, ff + 2*s, closure);
1233 if(gameInfo.variant == VariantSuper) goto Amazon;
1234 if (rf > 0 && WhitePiece(board[rf - 1][ff]))
1235 callback(board, flags,
1236 rf <= promoRank ? BlackPromotion : NormalMove,
1237 rf, ff, rf - 1, ff, closure);
1238 for (s = -1; s <= 1; s += 2) {
1239 if (rf > 0 && ff + s >= BOARD_LEFT && ff + s < BOARD_RGHT && board[rf - 1][ff + s] == EmptySquare)
1240 callback(board, flags,
1241 rf <= promoRank ? BlackPromotion : NormalMove,
1242 rf, ff, rf - 1, ff + s, closure);
1243 if (rf == BOARD_HEIGHT-2 && ff + 2*s >= BOARD_LEFT && ff + 2*s < BOARD_RGHT && board[rf-2][ff + 2*s] == EmptySquare )
1244 callback(board, flags, NormalMove, rf, ff, rf-2, ff + 2*s, closure);
1248 case SHOGI WhiteNothing:
1249 case SHOGI BlackNothing:
1250 case SHOGI WhiteLion:
1251 case SHOGI BlackLion:
1254 for(rt = rf - 2; rt <= rf + 2; rt++) for(ft = ff - 2; ft <= ff + 2; ft++) {
1255 if (rt < 0 || rt >= BOARD_HEIGHT || ft < BOARD_LEFT || ft >= BOARD_RGHT) continue;
1256 if (!(ff == ft && rf == rt) && SameColor(board[rf][ff], board[rt][ft])) continue;
1257 i = (killX >= 0 && (rt-killY)*(rt-killY) + (killX-ft)*(killX-ft) < 3); legNr += 2*i;
1258 callback(board, flags, (rt-rf)*(rt-rf) + (ff-ft)*(ff-ft) < 3 && board[rt][ft] != EmptySquare ? FirstLeg : NormalMove,
1259 rf, ff, rt, ft, closure);
1264 case SHOGI WhiteFalcon:
1265 case SHOGI BlackFalcon:
1266 case SHOGI WhitePDagger:
1267 case SHOGI BlackPDagger:
1268 SlideSideways(board, flags, rf, ff, callback, closure);
1269 StepVertical(board, flags, rf, ff, callback, closure);
1272 case SHOGI WhiteCobra:
1273 case SHOGI BlackCobra:
1274 StepVertical(board, flags, rf, ff, callback, closure);
1277 case SHOGI (PROMO WhiteFerz):
1278 if(gameInfo.variant == VariantShogi) goto WhiteGold;
1279 case SHOGI (PROMO BlackFerz):
1280 if(gameInfo.variant == VariantShogi) goto BlackGold;
1281 case SHOGI WhitePSword:
1282 case SHOGI BlackPSword:
1283 SlideVertical(board, flags, rf, ff, callback, closure);
1284 StepSideways(board, flags, rf, ff, callback, closure);
1287 case SHOGI WhiteUnicorn:
1288 case SHOGI BlackUnicorn:
1289 Ferz(board, flags, rf, ff, callback, closure);
1290 StepVertical(board, flags, rf, ff, callback, closure);
1293 case SHOGI WhiteMan:
1294 StepDiagForward(board, flags, rf, ff, callback, closure);
1295 StepVertical(board, flags, rf, ff, callback, closure);
1298 case SHOGI BlackMan:
1299 StepDiagBackward(board, flags, rf, ff, callback, closure);
1300 StepVertical(board, flags, rf, ff, callback, closure);
1303 case SHOGI WhiteHCrown:
1304 case SHOGI BlackHCrown:
1305 Bishop(board, flags, rf, ff, callback, closure);
1306 SlideSideways(board, flags, rf, ff, callback, closure);
1309 case SHOGI WhiteCrown:
1310 case SHOGI BlackCrown:
1311 Bishop(board, flags, rf, ff, callback, closure);
1312 SlideVertical(board, flags, rf, ff, callback, closure);
1315 case SHOGI WhiteCat:
1316 Sting(board, flags, rf, ff, 1, 0, callback, closure);
1317 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1318 if(killX >= 0) break;
1319 Bishop(board, flags, rf, ff, callback, closure);
1320 SlideSideways(board, flags, rf, ff, callback, closure);
1321 SlideBackward(board, flags, rf, ff, callback, closure);
1324 case SHOGI BlackCat:
1325 Sting(board, flags, rf, ff, -1, 0, callback, closure);
1326 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1327 if(killX >= 0) break;
1328 Bishop(board, flags, rf, ff, callback, closure);
1329 SlideSideways(board, flags, rf, ff, callback, closure);
1330 SlideForward(board, flags, rf, ff, callback, closure);
1333 case SHOGI WhiteDagger:
1334 Sting(board, flags, rf, ff, 1, 1, callback, closure);
1335 Sting(board, flags, rf, ff, 1, -1, callback, closure);
1336 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1337 if(killX >= 0) break;
1338 Rook(board, flags, rf, ff, callback, closure);
1339 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1342 case SHOGI BlackDagger:
1343 Sting(board, flags, rf, ff, -1, 1, callback, closure);
1344 Sting(board, flags, rf, ff, -1, -1, callback, closure);
1345 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1346 if(killX >= 0) break;
1347 Rook(board, flags, rf, ff, callback, closure);
1348 SlideDiagForward(board, flags, rf, ff, callback, closure);
1351 case SHOGI WhiteDolphin:
1352 case SHOGI BlackHorse:
1353 SlideDiagBackward(board, flags, rf, ff, callback, closure);
1354 SlideVertical(board, flags, rf, ff, callback, closure);
1357 case SHOGI BlackDolphin:
1358 case SHOGI WhiteHorse:
1359 SlideDiagForward(board, flags, rf, ff, callback, closure);
1360 SlideVertical(board, flags, rf, ff, callback, closure);
1363 case SHOGI WhiteLance:
1364 SlideForward(board, flags, rf, ff, callback, closure);
1367 case SHOGI BlackLance:
1368 SlideBackward(board, flags, rf, ff, callback, closure);
1371 case WhiteFalcon: // [HGM] wild: for wildcards, self-capture symbolizes move to anywhere
1375 callback(board, flags, NormalMove, rf, ff, rf, ff, closure);
1388 int rFilter, fFilter; // [HGM] speed: sorry, but I get a bit tired of this closure madness
1389 Board xqCheckers, nullBoard;
1391 extern void GenLegalCallback P((Board board, int flags, ChessMove kind,
1392 int rf, int ff, int rt, int ft,
1396 GenLegalCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1398 register GenLegalClosure *cl = (GenLegalClosure *) closure;
1400 if(rFilter >= 0 && rFilter != rt || fFilter >= 0 && fFilter != ft) return; // [HGM] speed: ignore moves with wrong to-square
1402 if (board[EP_STATUS] == EP_IRON_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)) return; //[HGM] lion
1404 if (!(flags & F_IGNORE_CHECK) ) {
1405 int check, promo = (gameInfo.variant == VariantSpartan && kind == BlackPromotion);
1408 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1409 kings += (board[r][f] == BlackKing);
1413 board[rf][ff] = BlackKing; // [HGM] spartan: promote to King before check-test
1415 check = CheckTest(board, flags, rf, ff, rt, ft,
1416 kind == WhiteCapturesEnPassant ||
1417 kind == BlackCapturesEnPassant);
1418 if(promo) board[rf][ff] = BlackLance;
1421 if (flags & F_ATOMIC_CAPTURE) {
1422 if (board[rt][ft] != EmptySquare ||
1423 kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant) {
1425 ChessSquare king = (flags & F_WHITE_ON_MOVE) ? WhiteKing : BlackKing;
1426 if (board[rf][ff] == king) return;
1427 for (r = rt-1; r <= rt+1; r++) {
1428 for (f = ft-1; f <= ft+1; f++) {
1429 if (r >= 0 && r < BOARD_HEIGHT && f >= BOARD_LEFT && f < BOARD_RGHT &&
1430 board[r][f] == king) return;
1435 cl->cb(board, flags, kind, rf, ff, rt, ft, cl->cl);
1442 int captures; // [HGM] losers
1443 } LegalityTestClosure;
1446 /* Like GenPseudoLegal, but (1) include castling moves, (2) unless
1447 F_IGNORE_CHECK is set in the flags, omit moves that would leave the
1448 king in check, and (3) if F_ATOMIC_CAPTURE is set in the flags, omit
1449 moves that would destroy your own king. The CASTLE_OK flags are
1450 true if castling is not yet ruled out by a move of the king or
1451 rook. Return TRUE if the player on move is currently in check and
1452 F_IGNORE_CHECK is not set. [HGM] add castlingRights parameter */
1454 GenLegal (Board board, int flags, MoveCallback callback, VOIDSTAR closure, ChessSquare filter)
1457 int ff, ft, k, left, right, swap;
1458 int ignoreCheck = (flags & F_IGNORE_CHECK) != 0;
1459 ChessSquare wKing = WhiteKing, bKing = BlackKing, *castlingRights = board[CASTLING];
1460 int inCheck = !ignoreCheck && CheckTest(board, flags, -1, -1, -1, -1, FALSE); // kludge alert: this would mark pre-existing checkers if status==1
1465 xqCheckers[EP_STATUS] *= 2; // quasi: if previous CheckTest has been marking, we now set flag for suspending same checkers
1466 if(filter == EmptySquare) rFilter = fFilter = -1; // [HGM] speed: do not filter on square if we do not filter on piece
1467 GenPseudoLegal(board, flags, GenLegalCallback, (VOIDSTAR) &cl, filter);
1469 if (inCheck) return TRUE;
1471 /* Generate castling moves */
1472 if(gameInfo.variant == VariantKnightmate) { /* [HGM] Knightmate */
1473 wKing = WhiteUnicorn; bKing = BlackUnicorn;
1476 p = (flags & F_WHITE_ON_MOVE ? pieceDesc[wKing] : pieceDesc[bKing]);
1477 if(p && strchr(p, 'O')) return FALSE; // [HGM] gen: castlings were already generated from string
1479 for (ff = BOARD_WIDTH>>1; ff >= (BOARD_WIDTH-1)>>1; ff-- /*ics wild 1*/) {
1480 if ((flags & F_WHITE_ON_MOVE) &&
1481 (flags & F_WHITE_KCASTLE_OK) &&
1482 board[0][ff] == wKing &&
1483 board[0][ff + 1] == EmptySquare &&
1484 board[0][ff + 2] == EmptySquare &&
1485 board[0][BOARD_RGHT-3] == EmptySquare &&
1486 board[0][BOARD_RGHT-2] == EmptySquare &&
1487 board[0][BOARD_RGHT-1] == WhiteRook &&
1488 castlingRights[0] != NoRights && /* [HGM] check rights */
1489 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1491 (!CheckTest(board, flags, 0, ff, 0, ff + 1, FALSE) &&
1492 !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-3, FALSE) &&
1493 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, 0, ff, 0, BOARD_RGHT-2, FALSE)) &&
1494 !CheckTest(board, flags, 0, ff, 0, ff + 2, FALSE)))) {
1496 callback(board, flags,
1497 ff==BOARD_WIDTH>>1 ? WhiteKingSideCastle : WhiteKingSideCastleWild,
1498 0, ff, 0, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1500 if ((flags & F_WHITE_ON_MOVE) &&
1501 (flags & F_WHITE_QCASTLE_OK) &&
1502 board[0][ff] == wKing &&
1503 board[0][ff - 1] == EmptySquare &&
1504 board[0][ff - 2] == EmptySquare &&
1505 board[0][BOARD_LEFT+2] == EmptySquare &&
1506 board[0][BOARD_LEFT+1] == EmptySquare &&
1507 board[0][BOARD_LEFT+0] == WhiteRook &&
1508 castlingRights[1] != NoRights && /* [HGM] check rights */
1509 ( castlingRights[2] == ff || castlingRights[6] == ff ) &&
1511 (!CheckTest(board, flags, 0, ff, 0, ff - 1, FALSE) &&
1512 !CheckTest(board, flags, 0, ff, 0, BOARD_LEFT+3, FALSE) &&
1513 !CheckTest(board, flags, 0, ff, 0, ff - 2, FALSE)))) {
1515 callback(board, flags,
1516 ff==BOARD_WIDTH>>1 ? WhiteQueenSideCastle : WhiteQueenSideCastleWild,
1517 0, ff, 0, ff - ((gameInfo.boardWidth+2)>>2), closure);
1519 if (!(flags & F_WHITE_ON_MOVE) &&
1520 (flags & F_BLACK_KCASTLE_OK) &&
1521 board[BOARD_HEIGHT-1][ff] == bKing &&
1522 board[BOARD_HEIGHT-1][ff + 1] == EmptySquare &&
1523 board[BOARD_HEIGHT-1][ff + 2] == EmptySquare &&
1524 board[BOARD_HEIGHT-1][BOARD_RGHT-3] == EmptySquare &&
1525 board[BOARD_HEIGHT-1][BOARD_RGHT-2] == EmptySquare &&
1526 board[BOARD_HEIGHT-1][BOARD_RGHT-1] == BlackRook &&
1527 castlingRights[3] != NoRights && /* [HGM] check rights */
1528 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1530 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 1, FALSE) &&
1531 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-3, FALSE) &&
1532 (gameInfo.variant != VariantJanus || !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_RGHT-2, FALSE)) &&
1533 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + 2, FALSE)))) {
1535 callback(board, flags,
1536 ff==BOARD_WIDTH>>1 ? BlackKingSideCastle : BlackKingSideCastleWild,
1537 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff + ((gameInfo.boardWidth+2)>>2) + (gameInfo.variant == VariantJanus), closure);
1539 if (!(flags & F_WHITE_ON_MOVE) &&
1540 (flags & F_BLACK_QCASTLE_OK) &&
1541 board[BOARD_HEIGHT-1][ff] == bKing &&
1542 board[BOARD_HEIGHT-1][ff - 1] == EmptySquare &&
1543 board[BOARD_HEIGHT-1][ff - 2] == EmptySquare &&
1544 board[BOARD_HEIGHT-1][BOARD_LEFT+2] == EmptySquare &&
1545 board[BOARD_HEIGHT-1][BOARD_LEFT+1] == EmptySquare &&
1546 board[BOARD_HEIGHT-1][BOARD_LEFT+0] == BlackRook &&
1547 castlingRights[4] != NoRights && /* [HGM] check rights */
1548 ( castlingRights[5] == ff || castlingRights[7] == ff ) &&
1550 (!CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 1, FALSE) &&
1551 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, BOARD_LEFT+3, FALSE) &&
1552 !CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - 2, FALSE)))) {
1554 callback(board, flags,
1555 ff==BOARD_WIDTH>>1 ? BlackQueenSideCastle : BlackQueenSideCastleWild,
1556 BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ff - ((gameInfo.boardWidth+2)>>2), closure);
1560 if((swap = gameInfo.variant == VariantSChess) || flags & F_FRC_TYPE_CASTLING) {
1562 /* generate all potential FRC castling moves (KxR), ignoring flags */
1563 /* [HGM] test if the Rooks we find have castling rights */
1564 /* In S-Chess we generate RxK for allowed castlings, for gating at Rook square */
1567 if ((flags & F_WHITE_ON_MOVE) != 0) {
1568 ff = castlingRights[2]; /* King file if we have any rights */
1569 if(ff != NoRights && board[0][ff] == WhiteKing) {
1570 if (appData.debugMode) {
1571 fprintf(debugFP, "FRC castling, %d %d %d %d %d %d\n",
1572 castlingRights[0],castlingRights[1],ff,castlingRights[3],castlingRights[4],castlingRights[5]);
1574 ft = castlingRights[0]; /* Rook file if we have H-side rights */
1576 right = BOARD_RGHT-2;
1577 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1578 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1579 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1580 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1581 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1582 if(ft != NoRights && board[0][ft] == WhiteRook) {
1583 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteHSideCastleFR, 0, ff, 0, ft, closure);
1584 if(swap) callback(board, flags, WhiteHSideCastleFR, 0, ft, 0, ff, closure);
1587 ft = castlingRights[1]; /* Rook file if we have A-side rights */
1588 left = BOARD_LEFT+2;
1590 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1591 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1592 if(k != ft && board[0][k] != EmptySquare) ft = NoRights;
1593 if(ft == 0 && ff != 1 && board[0][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b1 */
1594 if(ff > BOARD_LEFT+2)
1595 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1596 if(!ignoreCheck && CheckTest(board, flags, 0, ff, 0, k, FALSE)) ft = NoRights;
1597 if(ft != NoRights && board[0][ft] == WhiteRook) {
1598 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, WhiteASideCastleFR, 0, ff, 0, ft, closure);
1599 if(swap) callback(board, flags, WhiteASideCastleFR, 0, ft, 0, ff, closure);
1603 ff = castlingRights[5]; /* King file if we have any rights */
1604 if(ff != NoRights && board[BOARD_HEIGHT-1][ff] == BlackKing) {
1605 ft = castlingRights[3]; /* Rook file if we have H-side rights */
1607 right = BOARD_RGHT-2;
1608 if(ff == BOARD_RGHT-2) left = right = ff-1; /* special case */
1609 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1610 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1611 for(k=left; k<right && ft != NoRights; k++) /* then if not checked */
1612 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1613 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1614 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1615 if(swap) callback(board, flags, BlackHSideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1618 ft = castlingRights[4]; /* Rook file if we have A-side rights */
1619 left = BOARD_LEFT+2;
1621 if(ff <= BOARD_LEFT+2) { left = ff+1; right = BOARD_LEFT+3; }
1622 for(k=left; k<=right && ft != NoRights; k++) /* first test if blocked */
1623 if(k != ft && board[BOARD_HEIGHT-1][k] != EmptySquare) ft = NoRights;
1624 if(ft == 0 && ff != 1 && board[BOARD_HEIGHT-1][1] != EmptySquare) ft = NoRights; /* Rook can be blocked on b8 */
1625 if(ff > BOARD_LEFT+2)
1626 for(k=left+1; k<=right && ft != NoRights; k++) /* then if not checked */
1627 if(!ignoreCheck && CheckTest(board, flags, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, k, FALSE)) ft = NoRights;
1628 if(ft != NoRights && board[BOARD_HEIGHT-1][ft] == BlackRook) {
1629 if(flags & F_FRC_TYPE_CASTLING) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ff, BOARD_HEIGHT-1, ft, closure);
1630 if(swap) callback(board, flags, BlackASideCastleFR, BOARD_HEIGHT-1, ft, BOARD_HEIGHT-1, ff, closure);
1647 extern void CheckTestCallback P((Board board, int flags, ChessMove kind,
1648 int rf, int ff, int rt, int ft,
1653 CheckTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1655 register CheckTestClosure *cl = (CheckTestClosure *) closure;
1657 if (rt == cl->rking && ft == cl->fking) {
1658 if(xqCheckers[EP_STATUS] >= 2 && xqCheckers[rf][ff]) return; // checker is piece with suspended checking power
1660 xqCheckers[rf][ff] = xqCheckers[EP_STATUS] & 1; // remember who is checking (if status == 1)
1662 if( board[EP_STATUS] == EP_ROYAL_LION && (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion)
1663 && (gameInfo.variant != VariantLion || board[rf][ff] != WhiteKing && board[rf][ff] != BlackKing) )
1664 cl->check++; // [HGM] lion: forbidden counterstrike against Lion equated to putting yourself in check
1668 /* If the player on move were to move from (rf, ff) to (rt, ft), would
1669 he leave himself in check? Or if rf == -1, is the player on move
1670 in check now? enPassant must be TRUE if the indicated move is an
1671 e.p. capture. The possibility of castling out of a check along the
1672 back rank is not accounted for (i.e., we still return nonzero), as
1673 this is illegal anyway. Return value is the number of times the
1674 king is in check. */
1676 CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant)
1678 CheckTestClosure cl;
1679 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1680 ChessSquare captured = EmptySquare, ep=0, trampled=0;
1681 int saveKill = killX;
1682 /* Suppress warnings on uninitialized variables */
1684 if(gameInfo.variant == VariantXiangqi)
1685 king = flags & F_WHITE_ON_MOVE ? WhiteWazir : BlackWazir;
1686 if(gameInfo.variant == VariantKnightmate)
1687 king = flags & F_WHITE_ON_MOVE ? WhiteUnicorn : BlackUnicorn;
1688 if(gameInfo.variant == VariantChu || gameInfo.variant == VariantShogi) { // strictly speaking this is not needed, as Chu officially has no check
1689 int r, f, k = king, royals=0, prince = flags & F_WHITE_ON_MOVE ? WhiteMonarch : BlackMonarch;
1690 if(gameInfo.variant == VariantShogi) prince -= 11; // White/BlackFalcon
1691 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1692 if(board[r][f] == k || board[r][f] == prince) {
1693 if(++royals > 1) return FALSE; // no check if we have two royals (ignores double captureby Lion!)
1694 king = board[r][f]; // remember hich one we had
1701 captured = board[rf][ft];
1702 board[rf][ft] = EmptySquare;
1704 captured = board[rt][ft];
1705 if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; }
1707 if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
1708 board[rt][ft] = board[rf][ff];
1709 if(rf != rt || ff != ft) board[rf][ff] = EmptySquare;
1711 ep = board[EP_STATUS];
1712 if( captured == WhiteLion || captured == BlackLion ) { // [HGM] lion: Chu Lion-capture rules
1713 ChessSquare victim = saveKill < 0 ? EmptySquare : trampled;
1714 if( (board[rt][ft] == WhiteLion || board[rt][ft] == BlackLion) && // capturer is Lion
1715 (ff - ft > 1 || ft - ff > 1 || rf - rt > 1 || rt - rf > 1) && // captures from a distance
1716 (victim == EmptySquare || victim == WhitePawn || victim == BlackPawn // no or worthless 'bridge'
1717 || victim == WhiteCobra || victim == BlackCobra) ) // (Pawn or Go Between)
1718 board[EP_STATUS] = EP_ROYAL_LION; // on distant Lion x Lion victim must not be pseudo-legally protected
1722 /* For compatibility with ICS wild 9, we scan the board in the
1723 order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
1724 and we test only whether that one is in check. */
1725 for (cl.fking = BOARD_LEFT+0; cl.fking < BOARD_RGHT; cl.fking++)
1726 for (cl.rking = 0; cl.rking < BOARD_HEIGHT; cl.rking++) {
1727 if (board[cl.rking][cl.fking] == king) {
1729 if(gameInfo.variant == VariantXiangqi) {
1730 /* [HGM] In Xiangqi opposing Kings means check as well */
1732 dir = (king >= BlackPawn) ? -1 : 1;
1733 for( i=cl.rking+dir; i>=0 && i<BOARD_HEIGHT &&
1734 board[i][cl.fking] == EmptySquare; i+=dir );
1735 if(i>=0 && i<BOARD_HEIGHT &&
1736 board[i][cl.fking] == (dir>0 ? BlackWazir : WhiteWazir) )
1739 GenPseudoLegal(board, flags ^ F_WHITE_ON_MOVE, CheckTestCallback, (VOIDSTAR) &cl, EmptySquare);
1740 if(gameInfo.variant != VariantSpartan || cl.check == 0) // in Spartan Chess go on to test if other King is checked too
1741 goto undo_move; /* 2-level break */
1748 if(rf != DROP_RANK) // [HGM] drop
1749 board[rf][ff] = board[rt][ft];
1751 board[rf][ft] = captured;
1752 board[rt][ft] = EmptySquare;
1754 if(saveKill >= 0) board[killY][killX = saveKill] = trampled;
1755 board[rt][ft] = captured;
1757 board[EP_STATUS] = ep;
1760 return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
1764 HasLion (Board board, int flags)
1766 int lion = F_WHITE_ON_MOVE & flags ? WhiteLion : BlackLion;
1768 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
1769 if(board[r][f] == lion) return 1;
1774 LegalDrop (Board board, int flags, ChessSquare piece, int rt, int ft)
1775 { // [HGM] put drop legality testing in separate routine for clarity
1777 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1778 if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
1779 n = PieceToNumber(piece);
1780 if((gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
1781 && gameInfo.variant != VariantBughouse) // in bughouse we don't check for availability, because ICS doesn't always tell us
1782 return ImpossibleMove; // piece not available
1783 if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
1784 if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
1785 (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
1786 piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
1787 piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
1788 if(piece == WhitePawn || piece == BlackPawn) {
1789 int r, max = 1 + (BOARD_HEIGHT == 7); // two Pawns per file in Tori!
1790 for(r=1; r<BOARD_HEIGHT-1; r++)
1791 if(!(max -= (board[r][ft] == piece))) return IllegalMove; // or there already is a Pawn in file
1792 // should still test if we mate with this Pawn
1794 } else if(gameInfo.variant == VariantSChess) { // only back-rank drops
1795 if (rt != (piece < BlackPawn ? 0 : BOARD_HEIGHT-1)) return IllegalMove;
1797 if( (piece == WhitePawn || piece == BlackPawn) &&
1798 (rt == 0 || rt == BOARD_HEIGHT -1 ) )
1799 return IllegalMove; /* no pawn drops on 1st/8th */
1801 if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
1802 if (!(flags & F_IGNORE_CHECK) &&
1803 CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
1804 return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
1807 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
1808 int rf, int ff, int rt, int ft,
1812 LegalityTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1814 register LegalityTestClosure *cl = (LegalityTestClosure *) closure;
1816 if(board[rt][ft] != EmptySquare || kind==WhiteCapturesEnPassant || kind==BlackCapturesEnPassant)
1817 cl->captures++; // [HGM] losers: count legal captures
1818 if (rf == cl->rf && ff == cl->ff && rt == cl->rt && ft == cl->ft)
1823 LegalityTest (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar)
1825 LegalityTestClosure cl; ChessSquare piece, filterPiece;
1827 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
1828 if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
1829 piece = filterPiece = board[rf][ff];
1830 if(PieceToChar(piece) == '~') filterPiece = DEMOTED(piece);
1832 /* [HGM] Cobra and Falcon are wildcard pieces; consider all their moves legal */
1833 /* (perhaps we should disallow moves that obviously leave us in check?) */
1834 if((piece == WhiteFalcon || piece == BlackFalcon ||
1835 piece == WhiteCobra || piece == BlackCobra) && gameInfo.variant != VariantChu && !pieceDesc[piece])
1836 return CheckTest(board, flags, rf, ff, rt, ft, FALSE) ? IllegalMove : NormalMove;
1840 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
1841 cl.ft = fFilter = ft;
1842 cl.kind = IllegalMove;
1843 cl.captures = 0; // [HGM] losers: prepare to count legal captures.
1844 if(flags & F_MANDATORY_CAPTURE) filterPiece = EmptySquare; // [HGM] speed: do not filter in suicide, to find all captures
1845 GenLegal(board, flags, LegalityTestCallback, (VOIDSTAR) &cl, filterPiece);
1846 if((flags & F_MANDATORY_CAPTURE) && cl.captures && board[rt][ft] == EmptySquare
1847 && cl.kind != WhiteCapturesEnPassant && cl.kind != BlackCapturesEnPassant)
1848 return(IllegalMove); // [HGM] losers: if there are legal captures, non-capts are illegal
1850 if(promoChar == 'x') promoChar = NULLCHAR; // [HGM] is this ever the case?
1851 if(gameInfo.variant == VariantSChess && promoChar && promoChar != '=' && board[rf][ff] != WhitePawn && board[rf][ff] != BlackPawn) {
1852 if(board[rf][ff] < BlackPawn) { // white
1853 if(rf != 0) return IllegalMove; // must be on back rank
1854 if(!(board[VIRGIN][ff] & VIRGIN_W)) return IllegalMove; // non-virgin
1855 if(board[PieceToNumber(CharToPiece(ToUpper(promoChar)))][BOARD_WIDTH-2] == 0) return ImpossibleMove;// must be in stock
1856 if(cl.kind == WhiteHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1857 if(cl.kind == WhiteASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1859 if(rf != BOARD_HEIGHT-1) return IllegalMove;
1860 if(!(board[VIRGIN][ff] & VIRGIN_B)) return IllegalMove; // non-virgin
1861 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(promoChar)))][1] == 0) return ImpossibleMove;
1862 if(cl.kind == BlackHSideCastleFR && (ff == BOARD_RGHT-2 || ff == BOARD_RGHT-3)) return ImpossibleMove;
1863 if(cl.kind == BlackASideCastleFR && (ff == BOARD_LEFT+2 || ff == BOARD_LEFT+3)) return ImpossibleMove;
1866 if(gameInfo.variant == VariantChu) {
1867 if(cl.kind != NormalMove || promoChar == NULLCHAR || promoChar == '=') return cl.kind;
1868 if(promoChar != '+')
1869 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1870 if(PieceToChar(CHUPROMOTED(board[rf][ff])) != '+') {
1871 if(PieceToChar(CHUPROMOTED (board[rf][ff] < BlackPawn ? WhitePawn : BlackPawn)) != '.')
1872 return ImpossibleMove;
1874 return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1876 if(gameInfo.variant == VariantShogi) {
1877 /* [HGM] Shogi promotions. '=' means defer */
1878 if(rf != DROP_RANK && cl.kind == NormalMove) {
1879 ChessSquare piece = board[rf][ff];
1880 int zone = BOARD_HEIGHT/3 + (BOARD_HEIGHT == 8);
1882 if(promoChar == PieceToChar(BlackQueen)) promoChar = NULLCHAR; /* [HGM] Kludge */
1883 if(promoChar == 'd' && (piece == WhiteRook || piece == BlackRook) ||
1884 promoChar == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
1885 promoChar == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
1886 promoChar = '+'; // allowed ICS notations
1887 if(appData.debugMode)fprintf(debugFP,"SHOGI promoChar = %c\n", promoChar ? promoChar : '-');
1888 if(promoChar != NULLCHAR && promoChar != '+' && promoChar != '=')
1889 return CharToPiece(promoChar) == EmptySquare ? ImpossibleMove : IllegalMove;
1890 else if(flags & F_WHITE_ON_MOVE) {
1891 if( (int) piece < (int) WhiteWazir &&
1892 (rf >= BOARD_HEIGHT - zone || rt >= BOARD_HEIGHT - zone) ) {
1893 if( (piece == WhitePawn || piece == WhiteQueen) && rt > BOARD_HEIGHT-2 ||
1894 piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
1895 cl.kind = promoChar == '=' ? IllegalMove : WhitePromotion;
1896 else /* promotion optional, default is defer */
1897 cl.kind = promoChar == '+' ? WhitePromotion : WhiteNonPromotion;
1898 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1900 if( (int) piece < (int) BlackWazir && (rf < zone || rt < zone) ) {
1901 if( (piece == BlackPawn || piece == BlackQueen) && rt < 1 ||
1902 piece == BlackKnight && rt < 2 ) /* promotion obligatory */
1903 cl.kind = promoChar == '=' ? IllegalMove : BlackPromotion;
1904 else /* promotion optional, default is defer */
1905 cl.kind = promoChar == '+' ? BlackPromotion : BlackNonPromotion;
1906 } else cl.kind = promoChar == '+' ? IllegalMove : NormalMove;
1910 if (promoChar != NULLCHAR) {
1911 if(cl.kind == NormalMove && promoChar == '+') { // allow shogi-style promotion is pieceToChar specifies them
1912 ChessSquare piece = board[rf][ff];
1913 if(piece < BlackPawn ? piece > WhiteMan : piece > BlackMan) return ImpossibleMove; // already promoted
1914 // should test if in zone, really
1915 if(gameInfo.variant == VariantChuChess && (piece == WhiteKnight || piece == BlackKnight) && HasLion(board, flags))
1917 if(PieceToChar(PROMOTED(piece)) == '+') return flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion;
1919 if(promoChar == '=') cl.kind = IllegalMove; else // [HGM] shogi: no deferred promotion outside Shogi
1920 if (cl.kind == WhitePromotion || cl.kind == BlackPromotion) {
1921 ChessSquare piece = CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(promoChar) : ToLower(promoChar));
1922 if(piece == EmptySquare)
1923 cl.kind = ImpossibleMove; // non-existing piece
1924 if(gameInfo.variant == VariantChuChess && promoChar == 'l' && HasLion(board, flags)) {
1925 cl.kind = IllegalMove; // no two Lions
1926 } else if(gameInfo.variant == VariantSpartan && cl.kind == BlackPromotion ) {
1927 if(promoChar != PieceToChar(BlackKing)) {
1928 if(CheckTest(board, flags, rf, ff, rt, ft, FALSE)) cl.kind = IllegalMove; // [HGM] spartan: only promotion to King was possible
1929 if(piece == BlackLance) cl.kind = ImpossibleMove;
1930 } else { // promotion to King allowed only if we do not have two yet
1931 int r, f, kings = 0;
1932 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) kings += (board[r][f] == BlackKing);
1933 if(kings == 2) cl.kind = IllegalMove;
1935 } else if(piece == WhitePawn && rt == BOARD_HEIGHT-1 ||
1936 piece == BlackPawn && rt == 0) cl.kind = IllegalMove; // cannot stay Pawn on last rank in any variant
1937 else if((piece == WhiteUnicorn || piece == BlackUnicorn) && gameInfo.variant == VariantKnightmate)
1938 cl.kind = IllegalMove; // promotion to Royal Knight not allowed
1939 else if((piece == WhiteKing || piece == BlackKing) && gameInfo.variant != VariantSuicide && gameInfo.variant != VariantGiveaway)
1940 cl.kind = IllegalMove; // promotion to King usually not allowed
1942 cl.kind = IllegalMove;
1952 extern void MateTestCallback P((Board board, int flags, ChessMove kind,
1953 int rf, int ff, int rt, int ft,
1957 MateTestCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
1959 register MateTestClosure *cl = (MateTestClosure *) closure;
1964 /* Return MT_NONE, MT_CHECK, MT_CHECKMATE, or MT_STALEMATE */
1966 MateTest (Board board, int flags)
1969 int inCheck, r, f, myPieces=0, hisPieces=0, nrKing=0;
1970 ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
1972 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) {
1973 // [HGM] losers: Count pieces and kings, to detect other unorthodox winning conditions
1974 nrKing += (board[r][f] == king); // stm has king
1975 if( board[r][f] != EmptySquare ) {
1976 if((int)board[r][f] <= (int)king && (int)board[r][f] >= (int)king - (int)WhiteKing + (int)WhitePawn)
1981 switch(gameInfo.variant) { // [HGM] losers: extinction wins
1982 case VariantShatranj:
1983 if(hisPieces == 1) return myPieces > 1 ? MT_BARE : MT_DRAW;
1987 if(nrKing == 0) return MT_NOKING;
1990 if(myPieces == 1) return MT_BARE;
1993 inCheck = GenLegal(board, flags, MateTestCallback, (VOIDSTAR) &cl, EmptySquare);
1994 // [HGM] 3check: yet to do!
1996 return inCheck ? MT_CHECK : MT_NONE;
1998 if(gameInfo.holdingsWidth && gameInfo.variant != VariantSuper && gameInfo.variant != VariantGreat
1999 && gameInfo.variant != VariantSChess && gameInfo.variant != VariantGrand) { // drop game
2000 int r, f, n, holdings = flags & F_WHITE_ON_MOVE ? BOARD_WIDTH-1 : 0;
2001 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++) if(board[r][f] == EmptySquare) // all empty squares
2002 for(n=0; n<BOARD_HEIGHT; n++) // all pieces in hand
2003 if(board[n][holdings] != EmptySquare) {
2004 int moveType = LegalDrop(board, flags, board[n][holdings], r, f);
2005 if(moveType == WhiteDrop || moveType == BlackDrop) return (inCheck ? MT_CHECK : MT_NONE); // we have legal drop
2008 if(gameInfo.variant == VariantSuicide) // [HGM] losers: always stalemate, since no check, but result varies
2009 return myPieces == hisPieces ? MT_STALEMATE :
2010 myPieces > hisPieces ? MT_STAINMATE : MT_STEALMATE;
2011 else if(gameInfo.variant == VariantLosers) return inCheck ? MT_TRICKMATE : MT_STEALMATE;
2012 else if(gameInfo.variant == VariantGiveaway) return MT_STEALMATE; // no check exists, stalemated = win
2014 return inCheck ? MT_CHECKMATE
2015 : (gameInfo.variant == VariantXiangqi || gameInfo.variant == VariantShatranj || IS_SHOGI(gameInfo.variant)) ?
2016 MT_STAINMATE : MT_STALEMATE;
2021 extern void DisambiguateCallback P((Board board, int flags, ChessMove kind,
2022 int rf, int ff, int rt, int ft,
2026 DisambiguateCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2028 register DisambiguateClosure *cl = (DisambiguateClosure *) closure;
2029 int wildCard = FALSE; ChessSquare piece = board[rf][ff];
2030 extern int kifu; // in parser.c
2032 // [HGM] wild: for wild-card pieces rt and rf are dummies
2033 if(piece == WhiteFalcon || piece == BlackFalcon ||
2034 piece == WhiteCobra || piece == BlackCobra)
2037 if ((cl->pieceIn == EmptySquare || cl->pieceIn == board[rf][ff]
2038 || PieceToChar(board[rf][ff]) == '~'
2039 && cl->pieceIn == (ChessSquare)(DEMOTED(board[rf][ff]))
2041 (cl->rfIn == -1 || cl->rfIn == rf) &&
2042 (cl->ffIn == -1 || cl->ffIn == ff) &&
2043 (cl->rtIn == -1 || cl->rtIn == rt || wildCard) &&
2044 (cl->ftIn == -1 || cl->ftIn == ft || wildCard)) {
2046 if(cl->count && rf == cl->rf && ff == cl->ff) return; // duplicate move
2048 if(cl->count == 1 && kifu & 0x7E && cl->rfIn == -1 && cl->ffIn == -1) { // traditional Shogi disambiguation required
2049 int this = 1, other = 1;
2050 if(kifu & 2) this &= (flags & 1 ? rt > rf : rt < rf), other &= (flags & 1 ? cl->rt > cl->rf : cl->rt < cl->rf);
2051 if(kifu & 4) this &= (flags & 1 ? rt < rf : rt > rf), other &= (flags & 1 ? cl->rt < cl->rf : cl->rt > cl->rf);
2052 if(kifu & 8) this &= (rf == rt), other &= (cl->rt == cl->rf);
2053 if(kifu & 0x10) this &= (flags & 1 ? ft <= ff : ft >= ff), other &= (flags & 1 ? cl->ft <= cl->ff : cl->ft >= cl->ff);
2054 if(kifu & 0x20) this &= (flags & 1 ? ft >= ff : ft <= ff), other &= (flags & 1 ? cl->ft >= cl->ff : cl->ft <= cl->ff);
2055 if(kifu & 0x40) this &= (ft == ff), other &= (cl->ft == cl->ff); // should never be used
2056 if(!other) cl->count--; // the old move did not satisfy the requested relative position, erase it
2057 if(!this) return; // the current move does not satisfy the requested relative position, ignore it
2061 if(cl->count == 1 || board[rt][ft] != EmptySquare) {
2062 // [HGM] oneclick: if multiple moves, be sure we remember capture
2063 cl->piece = board[rf][ff];
2066 cl->rt = wildCard ? cl->rtIn : rt;
2067 cl->ft = wildCard ? cl->ftIn : ft;
2070 cl->captures += (board[rt][ft] != EmptySquare); // [HGM] oneclick: count captures
2075 Disambiguate (Board board, int flags, DisambiguateClosure *closure)
2077 int illegal = 0; char c = closure->promoCharIn;
2079 if(quickFlag) flags = flags & ~1 | quickFlag & 1; // [HGM] speed: in quick mode quickFlag specifies side-to-move.
2080 closure->count = closure->captures = 0;
2081 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2082 closure->kind = ImpossibleMove;
2083 rFilter = closure->rtIn; // [HGM] speed: only consider moves to given to-square
2084 fFilter = closure->ftIn;
2085 if(quickFlag) { // [HGM] speed: try without check test first, because if that is not ambiguous, we are happy
2086 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2087 if(closure->count > 1) { // gamble did not pay off. retry with check test to resolve ambiguity
2088 closure->count = closure->captures = 0;
2089 closure->rf = closure->ff = closure->rt = closure->ft = 0;
2090 closure->kind = ImpossibleMove;
2091 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2094 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn); // [HGM] speed: only pieces of requested type
2095 if (closure->count == 0) {
2096 /* See if it's an illegal move due to check */
2098 GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
2099 if (closure->count == 0) {
2100 /* No, it's not even that */
2101 if(!appData.testLegality && !pieceDefs && closure->pieceIn != EmptySquare) {
2102 int f, r; // if there is only a single piece of the requested type on the board, use that
2103 closure->rt = closure->rtIn, closure->ft = closure->ftIn;
2104 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
2105 if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
2106 if(closure->count > 1) illegal = 0; // ambiguous
2108 if(closure->count == 0) {
2109 if (appData.debugMode) { int i, j;
2110 for(i=BOARD_HEIGHT-1; i>=0; i--) {
2111 for(j=0; j<BOARD_WIDTH; j++)
2112 fprintf(debugFP, "%3d", (int) board[i][j]);
2113 fprintf(debugFP, "\n");
2119 } else if(pieceDefs && closure->count > 1) { // [HGM] gen: move is ambiguous under engine-defined rules
2120 DisambiguateClosure spare = *closure;
2121 pieceDefs = FALSE; spare.count = 0; // See if the (erroneous) built-in rules would resolve that
2122 GenLegal(board, flags, DisambiguateCallback, (VOIDSTAR) &spare, closure->pieceIn);
2123 if(spare.count == 1) *closure = spare; // It does, so use those in stead (game from file saved before gen patch?)
2127 if (c == 'x') c = NULLCHAR; // get rid of any 'x' (which should never happen?)
2128 if(gameInfo.variant == VariantSChess && c && c != '=' && closure->piece != WhitePawn && closure->piece != BlackPawn) {
2129 if(closure->piece < BlackPawn) { // white
2130 if(closure->rf != 0) closure->kind = IllegalMove; // must be on back rank
2131 if(!(board[VIRGIN][closure->ff] & VIRGIN_W)) closure->kind = IllegalMove; // non-virgin
2132 if(board[PieceToNumber(CharToPiece(ToUpper(c)))][BOARD_WIDTH-2] == 0) closure->kind = ImpossibleMove;// must be in stock
2133 if(closure->kind == WhiteHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2134 if(closure->kind == WhiteASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2136 if(closure->rf != BOARD_HEIGHT-1) closure->kind = IllegalMove;
2137 if(!(board[VIRGIN][closure->ff] & VIRGIN_B)) closure->kind = IllegalMove; // non-virgin
2138 if(board[BOARD_HEIGHT-1-PieceToNumber(CharToPiece(ToLower(c)))][1] == 0) closure->kind = ImpossibleMove;
2139 if(closure->kind == BlackHSideCastleFR && (closure->ff == BOARD_RGHT-2 || closure->ff == BOARD_RGHT-3)) closure->kind = ImpossibleMove;
2140 if(closure->kind == BlackASideCastleFR && (closure->ff == BOARD_LEFT+2 || closure->ff == BOARD_LEFT+3)) closure->kind = ImpossibleMove;
2143 if(gameInfo.variant == VariantChu) {
2144 if(c == '+') closure->kind = (flags & F_WHITE_ON_MOVE ? WhitePromotion : BlackPromotion); // for now, accept any
2146 if(gameInfo.variant == VariantShogi) {
2147 /* [HGM] Shogi promotions. On input, '=' means defer, '+' promote. Afterwards, c is set to '+' for promotions, NULL other */
2148 if(closure->rfIn != DROP_RANK && closure->kind == NormalMove) {
2149 ChessSquare piece = closure->piece;
2150 int zone = BOARD_HEIGHT/3 + (BOARD_HEIGHT == 8);
2151 if (c == 'd' && (piece == WhiteRook || piece == BlackRook) ||
2152 c == 'h' && (piece == WhiteBishop || piece == BlackBishop) ||
2153 c == 'g' && (piece <= WhiteFerz || piece <= BlackFerz && piece >= BlackPawn) )
2154 c = '+'; // allowed ICS notations
2155 if(c != NULLCHAR && c != '+' && c != '=') closure->kind = IllegalMove; // otherwise specifying a piece is illegal
2156 else if(flags & F_WHITE_ON_MOVE) {
2157 if( (int) piece < (int) WhiteWazir &&
2158 (closure->rf >= BOARD_HEIGHT-zone || closure->rt >= BOARD_HEIGHT-zone) ) {
2159 if( (piece == WhitePawn || piece == WhiteQueen) && closure->rt > BOARD_HEIGHT-2 ||
2160 piece == WhiteKnight && closure->rt > BOARD_HEIGHT-3) /* promotion mandatory */
2161 closure->kind = c == '=' ? IllegalMove : WhitePromotion;
2162 else /* promotion optional, default is defer */
2163 closure->kind = c == '+' ? WhitePromotion : WhiteNonPromotion;
2164 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2166 if( (int) piece < (int) BlackWazir && (closure->rf < zone || closure->rt < zone) ) {
2167 if( (piece == BlackPawn || piece == BlackQueen) && closure->rt < 1 ||
2168 piece == BlackKnight && closure->rt < 2 ) /* promotion obligatory */
2169 closure->kind = c == '=' ? IllegalMove : BlackPromotion;
2170 else /* promotion optional, default is defer */
2171 closure->kind = c == '+' ? BlackPromotion : BlackNonPromotion;
2172 } else closure->kind = c == '+' ? IllegalMove : NormalMove;
2175 if(closure->kind == WhitePromotion || closure->kind == BlackPromotion) c = '+'; else
2176 if(closure->kind == WhiteNonPromotion || closure->kind == BlackNonPromotion) c = '=';
2178 if (closure->kind == WhitePromotion || closure->kind == BlackPromotion) {
2179 if(c == NULLCHAR) { // missing promoChar on mandatory promotion; use default for variant
2180 if(gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
2181 gameInfo.variant == VariantMakruk)
2182 c = PieceToChar(BlackFerz);
2183 else if(gameInfo.variant == VariantASEAN)
2184 c = PieceToChar(BlackRook);
2185 else if(gameInfo.variant == VariantGreat)
2186 c = PieceToChar(BlackMan);
2187 else if(gameInfo.variant == VariantGrand)
2188 closure->kind = closure->rt != 0 && closure->rt != BOARD_HEIGHT-1 ? NormalMove : AmbiguousMove; // no default in Grand Chess
2190 c = PieceToChar(BlackQueen);
2191 } else if(c == '=') closure->kind = IllegalMove; // no deferral outside Shogi
2192 else if(c == 'l' && gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2193 } else if (c == '+') { // '+' outside shogi, check if pieceToCharTable enabled it
2194 ChessSquare p = closure->piece;
2195 if(p > WhiteMan && p < BlackPawn || p > BlackMan || PieceToChar(PROMOTED(p)) != '+')
2196 closure->kind = ImpossibleMove; // used on non-promotable piece
2197 else if(gameInfo.variant == VariantChuChess && HasLion(board, flags)) closure->kind = IllegalMove;
2198 } else if (c != NULLCHAR) closure->kind = IllegalMove;
2200 closure->promoChar = ToLower(c); // this can be NULLCHAR! Note we keep original promoChar even if illegal.
2201 if(c != '+' && c != '=' && c != NULLCHAR && CharToPiece(flags & F_WHITE_ON_MOVE ? ToUpper(c) : ToLower(c)) == EmptySquare)
2202 closure->kind = ImpossibleMove; // but we cannot handle non-existing piece types!
2203 if (closure->count > 1) {
2204 closure->kind = AmbiguousMove;
2207 /* Note: If more than one illegal move matches, but no legal
2208 moves, we return IllegalMove, not AmbiguousMove. Caller
2209 can look at closure->count to detect this.
2211 closure->kind = IllegalMove;
2225 } CoordsToAlgebraicClosure;
2227 extern void CoordsToAlgebraicCallback P((Board board, int flags,
2228 ChessMove kind, int rf, int ff,
2229 int rt, int ft, VOIDSTAR closure));
2232 CoordsToAlgebraicCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2234 register CoordsToAlgebraicClosure *cl =
2235 (CoordsToAlgebraicClosure *) closure;
2237 if ((rt == cl->rt && ft == cl->ft || rt == rf && ft == ff) && // [HGM] null move matches any toSquare
2238 (board[rf][ff] == cl->piece
2239 || PieceToChar(board[rf][ff]) == '~' &&
2240 (ChessSquare) (DEMOTED(board[rf][ff])) == cl->piece)
2244 cl->kind = kind; /* this is the move we want */
2246 cl->file++; /* need file to rule out this move */
2250 cl->rank++; /* need rank to rule out this move */
2252 cl->either++; /* rank or file will rule out this move */
2258 /* Convert coordinates to normal algebraic notation.
2259 promoChar must be NULLCHAR or 'x' if not a promotion.
2262 CoordsToAlgebraic (Board board, int flags, int rf, int ff, int rt, int ft, int promoChar, char out[MOVE_LEN])
2266 char *outp = out, c, capture;
2267 CoordsToAlgebraicClosure cl;
2269 if (rf == DROP_RANK) {
2270 if(ff == EmptySquare) { strncpy(outp, "--",3); return NormalMove; } // [HGM] pass
2271 /* Bughouse piece drop */
2272 *outp++ = ToUpper(PieceToChar((ChessSquare) ff));
2277 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2279 return (flags & F_WHITE_ON_MOVE) ? WhiteDrop : BlackDrop;
2282 if (promoChar == 'x') promoChar = NULLCHAR;
2283 piece = board[rf][ff];
2284 if(PieceToChar(piece)=='~') piece = (ChessSquare)(DEMOTED(piece));
2289 kind = LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2290 if (kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2291 /* Keep short notation if move is illegal only because it
2292 leaves the player in check, but still return IllegalMove */
2293 kind = LegalityTest(board, flags|F_IGNORE_CHECK, rf, ff, rt, ft, promoChar);
2294 if (kind == IllegalMove) break;
2299 capture = board[rt][ft] != EmptySquare || kind == WhiteCapturesEnPassant || kind == BlackCapturesEnPassant;
2300 if (ff == ft && !capture) { /* [HGM] Xiangqi has straight noncapts! */
2301 /* Non-capture; use style "e5" */
2304 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2306 /* Capture; use style "exd5" */
2308 *outp++ = 'x'; /* [HGM] Xiangqi has sideway noncaptures across river! */
2312 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2314 /* Use promotion suffix style "=Q" */
2316 if (promoChar != NULLCHAR) {
2317 if(IS_SHOGI(gameInfo.variant)) {
2318 /* [HGM] ... but not in Shogi! */
2319 *outp++ = promoChar == '=' ? '=' : '+';
2322 *outp++ = ToUpper(promoChar);
2331 /* Fabien moved code: FRC castling first (if KxR), wild castling second */
2332 /* Code added by Tord: FRC castling. */
2333 if((piece == WhiteKing && board[rt][ft] == WhiteRook) ||
2334 (piece == BlackKing && board[rt][ft] == BlackRook)) {
2336 safeStrCpy(out, "O-O", MOVE_LEN);
2338 safeStrCpy(out, "O-O-O", MOVE_LEN);
2339 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2341 /* End of code added by Tord */
2342 /* Test for castling or ICS wild castling */
2343 /* Use style "O-O" (oh-oh) for PGN compatibility */
2344 else if (rf == rt &&
2345 rf == ((piece == WhiteKing) ? 0 : BOARD_HEIGHT-1) &&
2346 (ft - ff > 1 || ff - ft > 1) && // No castling if legal King move (on narrow boards!)
2347 ((ff == BOARD_WIDTH>>1 && (ft == BOARD_LEFT+2 || ft == BOARD_RGHT-2)) ||
2348 (ff == (BOARD_WIDTH-1)>>1 && (ft == BOARD_LEFT+1 || ft == BOARD_RGHT-3)))) {
2349 if(ft==BOARD_LEFT+1 || ft==BOARD_RGHT-2)
2350 snprintf(out, MOVE_LEN, "O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2352 snprintf(out, MOVE_LEN, "O-O-O%c%c", promoChar ? '/' : 0, ToUpper(promoChar));
2354 /* This notation is always unambiguous, unless there are
2355 kings on both the d and e files, with "wild castling"
2356 possible for the king on the d file and normal castling
2357 possible for the other. ICS rules for wild 9
2358 effectively make castling illegal for either king in
2359 this situation. So I am not going to worry about it;
2360 I'll just generate an ambiguous O-O in this case.
2362 return LegalityTest(board, flags, rf, ff, rt, ft, promoChar);
2365 /* else fall through */
2370 cl.rt = rFilter = rt; // [HGM] speed: filter on to-square
2371 cl.ft = fFilter = ft;
2373 cl.kind = IllegalMove;
2374 cl.rank = cl.file = cl.either = 0;
2375 c = PieceToChar(piece) ;
2376 GenLegal(board, flags, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED(piece))); // [HGM] speed
2378 if (cl.kind == IllegalMove && !(flags&F_IGNORE_CHECK)) {
2379 /* Generate pretty moves for moving into check, but
2380 still return IllegalMove.
2382 GenLegal(board, flags|F_IGNORE_CHECK, CoordsToAlgebraicCallback, (VOIDSTAR) &cl, c!='~' ? piece : (DEMOTED(piece)));
2383 if (cl.kind == IllegalMove) break;
2384 cl.kind = IllegalMove;
2387 /* Style is "Nf3" or "Nxf7" if this is unambiguous,
2388 else "Ngf3" or "Ngxf7",
2389 else "N1f3" or "N5xf7",
2390 else "Ng1f3" or "Ng5xf7".
2392 if( c == '~' || c == '+') {
2393 /* [HGM] print nonexistent piece as its demoted version */
2394 piece = (ChessSquare) (CHUDEMOTED(piece));
2396 if(c=='+') *outp++ = c;
2397 *outp++ = ToUpper(PieceToChar(piece));
2398 if(*outp = PieceSuffix(piece)) outp++;
2400 if (cl.file || (cl.either && !cl.rank)) {
2406 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2409 if(board[rt][ft] != EmptySquare)
2415 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2416 if (IS_SHOGI(gameInfo.variant)) {
2417 /* [HGM] in Shogi non-pawns can promote */
2418 *outp++ = promoChar; // Don't bother to correct move type, return value is never used!
2420 else if (gameInfo.variant == VariantChuChess && promoChar ||
2421 gameInfo.variant != VariantSuper && promoChar &&
2422 (piece == WhiteLance || piece == BlackLance) ) { // Lance sometimes represents Pawn
2424 *outp++ = ToUpper(promoChar);
2426 else if (gameInfo.variant == VariantSChess && promoChar) { // and in S-Chess we have gating
2428 *outp++ = ToUpper(promoChar);
2434 /* Moving a nonexistent piece */
2438 /* Not a legal move, even ignoring check.
2439 If there was a piece on the from square,
2440 use style "Ng1g3" or "Ng1xe8";
2441 if there was a pawn or nothing (!),
2442 use style "g1g3" or "g1xe8". Use "x"
2443 if a piece was on the to square, even
2444 a piece of the same color.
2448 if (piece != EmptySquare && piece != WhitePawn && piece != BlackPawn) {
2450 for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<=BOARD_RGHT; f++)
2451 c += (board[r][f] == piece); // count on-board pieces of given type
2452 *outp = PieceToChar(piece);
2453 if(*outp == '+') outp++, piece = CHUDEMOTED(piece);
2454 *outp++ = ToUpper(PieceToChar(piece));
2455 if(*outp = PieceSuffix(piece)) outp++;
2457 if(c != 1) { // [HGM] but if there is only one piece of the mentioned type, no from-square, thank you!
2461 else { *outp++ = (rf+ONE-'0')/10 + '0';*outp++ = (rf+ONE-'0')%10 + '0'; }
2463 if (board[rt][ft] != EmptySquare) *outp++ = 'x';
2467 else { *outp++ = (rt+ONE-'0')/10 + '0';*outp++ = (rt+ONE-'0')%10 + '0'; }
2468 /* Use promotion suffix style "=Q" */
2469 if (promoChar != NULLCHAR && promoChar != 'x') {
2471 *outp++ = ToUpper(promoChar);
2478 // [HGM] XQ: the following code serves to detect perpetual chasing (Asian rules)
2487 // I guess the following variables logically belong in the closure too, but I was too lazy and used globals
2489 int preyStackPointer, chaseStackPointer;
2492 unsigned char rf, ff, rt, ft;
2496 unsigned char rank, file;
2502 // there are three new callbacks for use with GenLegal: for adding captures, deleting them, and finding a recapture
2504 extern void AtacksCallback P((Board board, int flags, ChessMove kind,
2505 int rf, int ff, int rt, int ft,
2509 AttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2510 { // For adding captures that can lead to chase indictment to the chaseStack
2511 if(board[rt][ft] == EmptySquare) return; // non-capture
2512 if(board[rt][ft] == WhitePawn && rt < BOARD_HEIGHT/2) return; // Pawn before river can be chased
2513 if(board[rt][ft] == BlackPawn && rt >= BOARD_HEIGHT/2) return; // Pawn before river can be chased
2514 if(board[rf][ff] == WhitePawn || board[rf][ff] == BlackPawn) return; // Pawns are allowed to chase
2515 if(board[rf][ff] == WhiteWazir || board[rf][ff] == BlackWazir) return; // King is allowed to chase
2516 // move cannot be excluded from being a chase trivially (based on attacker and victim); save it on chaseStack
2517 chaseStack[chaseStackPointer].rf = rf;
2518 chaseStack[chaseStackPointer].ff = ff;
2519 chaseStack[chaseStackPointer].rt = rt;
2520 chaseStack[chaseStackPointer].ft = ft;
2521 chaseStackPointer++;
2524 extern void ExistingAtacksCallback P((Board board, int flags, ChessMove kind,
2525 int rf, int ff, int rt, int ft,
2529 ExistingAttacksCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2530 { // for removing pre-exsting captures from the chaseStack, to be left with newly created ones
2532 register ChaseClosure *cl = (ChaseClosure *) closure; //closure tells us the move played in the repeat loop
2534 if(board[rt][ft] == EmptySquare) return; // no capture
2535 if(rf == cl->rf && ff == cl->ff) { // attacks with same piece from new position are not considered new
2536 rf = cl->rt; ff = cl->ft; // doctor their fromSquare so they will be recognized in chaseStack
2538 // search move in chaseStack, and delete it if it occurred there (as we know now it is not a new capture)
2539 for(i=0; i<chaseStackPointer; i++) {
2540 if(chaseStack[i].rf == rf && chaseStack[i].ff == ff &&
2541 chaseStack[i].rt == rt && chaseStack[i].ft == ft ) {
2542 // move found on chaseStack, delete it by overwriting with move popped from top of chaseStack
2543 chaseStack[i] = chaseStack[--chaseStackPointer];
2549 extern void ProtectedCallback P((Board board, int flags, ChessMove kind,
2550 int rf, int ff, int rt, int ft,
2554 ProtectedCallback (Board board, int flags, ChessMove kind, int rf, int ff, int rt, int ft, VOIDSTAR closure)
2555 { // for determining if a piece (given through the closure) is protected
2556 register ChaseClosure *cl = (ChaseClosure *) closure; // closure tells us where to recapture
2558 if(rt == cl->rt && ft == cl->ft) cl->recaptures++; // count legal recaptures to this square
2559 if(appData.debugMode && board[rt][ft] != EmptySquare)
2560 fprintf(debugFP, "try %c%c%c%c=%d\n", ff+AAA, rf+ONE,ft+AAA, rt+ONE, cl->recaptures);
2563 extern char moveList[MAX_MOVES][MOVE_LEN];
2566 PerpetualChase (int first, int last)
2567 { // this routine detects if the side to move in the 'first' position is perpetually chasing (when not checking)
2570 ChessSquare captured;
2572 preyStackPointer = 0; // clear stack of chased pieces
2573 for(i=first; i<last; i+=2) { // for all positions with same side to move
2574 if(appData.debugMode) fprintf(debugFP, "judge position %i\n", i);
2575 chaseStackPointer = 0; // clear stack that is going to hold possible chases
2576 // determine all captures possible after the move, and put them on chaseStack
2577 GenLegal(boards[i+1], PosFlags(i), AttacksCallback, &cl, EmptySquare);
2578 if(appData.debugMode) { int n;
2579 for(n=0; n<chaseStackPointer; n++)
2580 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2581 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2582 fprintf(debugFP, ": all capts\n");
2584 // determine all captures possible before the move, and delete them from chaseStack
2585 cl.rf = moveList[i][1]-ONE; // prepare closure to pass move that led from i to i+1
2586 cl.ff = moveList[i][0]-AAA+BOARD_LEFT;
2587 cl.rt = moveList[i][3]-ONE;
2588 cl.ft = moveList[i][2]-AAA+BOARD_LEFT;
2589 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1; // giant kludge to make GenLegal ignore pre-existing checks
2590 GenLegal(boards[i], PosFlags(i), ExistingAttacksCallback, &cl, EmptySquare);
2591 xqCheckers[EP_STATUS] = 0; // disable the generation of quasi-legal moves again
2592 if(appData.debugMode) { int n;
2593 for(n=0; n<chaseStackPointer; n++)
2594 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2595 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2596 fprintf(debugFP, ": new capts after %c%c%c%c\n", cl.ff+AAA, cl.rf+ONE, cl.ft+AAA, cl.rt+ONE);
2598 // chaseSack now contains all captures made possible by the move
2599 for(j=0; j<chaseStackPointer; j++) { // run through chaseStack to identify true chases
2600 int attacker = (int)boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2601 int victim = (int)boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2603 if(attacker >= (int) BlackPawn) attacker = BLACK_TO_WHITE attacker; // convert to white, as piecee type
2604 if(victim >= (int) BlackPawn) victim = BLACK_TO_WHITE victim;
2606 if((attacker == WhiteKnight || attacker == WhiteCannon) && victim == WhiteRook)
2607 continue; // C or H attack on R is always chase; leave on chaseStack
2609 if(attacker == victim) {
2610 if(LegalityTest(boards[i+1], PosFlags(i+1), chaseStack[j].rt,
2611 chaseStack[j].ft, chaseStack[j].rf, chaseStack[j].ff, NULLCHAR) == NormalMove) {
2612 // we can capture back with equal piece, so this is no chase but a sacrifice
2613 chaseStack[j] = chaseStack[--chaseStackPointer]; // delete the capture from the chaseStack
2614 j--; /* ! */ continue;
2619 // the attack is on a lower piece, or on a pinned or blocked equal one
2620 CopyBoard(xqCheckers, nullBoard); xqCheckers[EP_STATUS] = 1;
2621 CheckTest(boards[i+1], PosFlags(i+1), -1, -1, -1, -1, FALSE); // if we deliver check with our move, the checkers get marked
2622 // test if the victim is protected by a true protector. First make the capture.
2623 captured = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2624 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = boards[i+1][chaseStack[j].rf][chaseStack[j].ff];
2625 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = EmptySquare;
2626 // Then test if the opponent can recapture
2627 cl.recaptures = 0; // prepare closure to pass recapture square and count moves to it
2628 cl.rt = chaseStack[j].rt;
2629 cl.ft = chaseStack[j].ft;
2630 if(appData.debugMode) {
2631 fprintf(debugFP, "test if we can recapture %c%c\n", cl.ft+AAA, cl.rt+ONE);
2633 xqCheckers[EP_STATUS] = 2; // causes GenLegal to ignore the checks we delivered with the move, in real life evaded before we captured
2634 GenLegal(boards[i+1], PosFlags(i+1), ProtectedCallback, &cl, EmptySquare); // try all moves
2635 xqCheckers[EP_STATUS] = 0; // disable quasi-legal moves again
2636 // unmake the capture
2637 boards[i+1][chaseStack[j].rf][chaseStack[j].ff] = boards[i+1][chaseStack[j].rt][chaseStack[j].ft];
2638 boards[i+1][chaseStack[j].rt][chaseStack[j].ft] = captured;
2639 // if a recapture was found, piece is protected, and we are not chasing it.
2640 if(cl.recaptures) { // attacked piece was defended by true protector, no chase
2641 chaseStack[j] = chaseStack[--chaseStackPointer]; // so delete from chaseStack
2645 // chaseStack now contains all moves that chased
2646 if(appData.debugMode) { int n;
2647 for(n=0; n<chaseStackPointer; n++)
2648 fprintf(debugFP, "%c%c%c%c ", chaseStack[n].ff+AAA, chaseStack[n].rf+ONE,
2649 chaseStack[n].ft+AAA, chaseStack[n].rt+ONE);
2650 fprintf(debugFP, ": chases\n");
2652 if(i == first) { // copy all people chased by first move of repeat cycle to preyStack
2653 for(j=0; j<chaseStackPointer; j++) {
2654 preyStack[j].rank = chaseStack[j].rt;
2655 preyStack[j].file = chaseStack[j].ft;
2657 preyStackPointer = chaseStackPointer;
2660 for(j=0; j<chaseStackPointer; j++) {
2661 for(k=0; k<preyStackPointer; k++) {
2662 // search the victim of each chase move on the preyStack (first occurrence)
2663 if(chaseStack[j].ft == preyStack[k].file && chaseStack[j].rt == preyStack[k].rank ) {
2664 if(k < tail) break; // piece was already identified as still being chased
2665 preyStack[preyStackPointer] = preyStack[tail]; // move chased piece to bottom part of preyStack
2666 preyStack[tail] = preyStack[k]; // by swapping
2667 preyStack[k] = preyStack[preyStackPointer];
2673 preyStackPointer = tail; // keep bottom part of preyStack, popping pieces unchased on move i.
2674 if(appData.debugMode) { int n;
2675 for(n=0; n<preyStackPointer; n++)
2676 fprintf(debugFP, "%c%c ", preyStack[n].file+AAA, preyStack[n].rank+ONE);
2677 fprintf(debugFP, "always chased upto ply %d\n", i);
2679 // now adjust the location of the chased pieces according to opponent move
2680 for(j=0; j<preyStackPointer; j++) {
2681 if(preyStack[j].rank == moveList[i+1][1]-ONE &&
2682 preyStack[j].file == moveList[i+1][0]-AAA+BOARD_LEFT) {
2683 preyStack[j].rank = moveList[i+1][3]-ONE;
2684 preyStack[j].file = moveList[i+1][2]-AAA+BOARD_LEFT;
2689 return preyStackPointer ? 256*(preyStack[preyStackPointer].file - BOARD_LEFT + AAA) + (preyStack[preyStackPointer].rank + ONE)
2690 : 0; // if any piece was left on preyStack, it has been perpetually chased,and we return the