2 Copyright (c) 1993 Richard V. Nash.
3 Copyright (c) 2000 Dan Papasian
4 Copyright (C) Andrew Tridgell 2002
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 // [HGM] some explanation of the parser code:
24 // The routine parse_move() calls is_move() to recognize some simple cases,
25 // like OO-castle and long algebraic with or without dash. What does not fall
26 // in this class is handed to alg_is_move(), whch is really a continuation
27 // of is_move(), to recognize SAN.
28 // Depending on the type of move syntax, parse_move can extract from- and to-square
29 // immediately, or transate the OO-castling to internal from-to representation.
30 // Only for SAN syntax the routine alg_pars_move() is called to extract the
31 // given elements, (through get_move_info(), which is the same as alg_is_move(),
32 // xcept that it does not discard the value of the elements), and disambiguate
33 // the move (i.e. determines the from-square) by looking for a piece of the given
34 // type on the board for which the move is pseudo-legal (using legal_move() ).
37 /* Simply tests if the input string is a move or not. */
38 /* If it matches patterns below */
39 /* Add to this list as you improve the move parser */
41 /* MS_COMPDASH e2-e4 */
42 /* MS_CASTLE o-o, o-o-o */
44 /* MS_ALG e4, Nd5 Ncd5 */
45 int is_move(const char *mstr)
47 int len = strlen(mstr);
48 /* remove the 'mates' marker */
49 if (mstr[len - 1] == '#')
52 if ((len > 3) && (mstr[len - 2] == '=' || mstr[len - 2] == '/'))
55 if (len == 4) { /* Test for e2e4 */
56 if (isfile(mstr[0]) && isrank(mstr[1]) &&
57 isfile(mstr[2]) && isrank(mstr[3])) {
61 if (len == 5) { /* Test for e2-e4 */
62 if (isfile(mstr[0]) && isrank(mstr[1]) &&
64 isfile(mstr[3]) && isrank(mstr[4])) {
68 if (len == 3) { /* Test for o-o */
69 if ((mstr[0] == 'o') && (mstr[1] == '-') && (mstr[2] == 'o')) {
72 if ((mstr[0] == 'O') && (mstr[1] == '-') && (mstr[2] == 'O')) {
75 if ((mstr[0] == '0') && (mstr[1] == '-') && (mstr[2] == '0')) {
79 if (len == 2) { /* Test for oo */
80 if ((mstr[0] == 'o') && (mstr[1] == 'o')) {
83 if ((mstr[0] == 'O') && (mstr[1] == 'O')) {
86 if ((mstr[0] == '0') && (mstr[1] == '0')) {
90 if (len == 5) { /* Test for o-o-o */
91 if ((mstr[0] == 'o') && (mstr[1] == '-') && (mstr[2] == 'o') && (mstr[3] == '-') && (mstr[4] == 'o')) {
94 if ((mstr[0] == 'O') && (mstr[1] == '-') && (mstr[2] == 'O') && (mstr[3] == '-') && (mstr[4] == 'O')) {
97 if ((mstr[0] == '0') && (mstr[1] == '-') && (mstr[2] == '0') && (mstr[3] == '-') && (mstr[4] == '0')) {
101 if (len == 3) { /* Test for ooo */
102 if ((mstr[0] == 'o') && (mstr[1] == 'o') && (mstr[2] == 'o')) {
105 if ((mstr[0] == 'O') && (mstr[1] == 'O') && (mstr[2] == 'O')) {
108 if ((mstr[0] == '0') && (mstr[1] == '0') && (mstr[2] == '0')) {
112 return alg_is_move(mstr);
116 int NextPieceLoop(board_t b, int *f, int *r, int color, int w, int h)
126 if ((b[*f][*r] != NOPIECE) && iscolor(b[*f][*r], color))
132 int InitPieceLoop(board_t b, int *f, int *r, int color)
139 /* All of the routines assume that the obvious problems have been checked */
140 /* See legal_move() */
141 static int legal_pawn_move( struct game_state_t *gs, int ff, int fr, int tf, int tr )
144 if (gs->board[tf][tr] != NOPIECE && !gs->palace && gs->promoType != 3) return 0; // [HGM] XQ and Shogi pawns can capture straight ahead
145 if (gs->onMove == WHITE) {
146 if (tr - fr == 1) return 1;
147 if ((fr <= gs->pawnDblStep) && (tr - fr == 2) && gs->board[ff][fr+1]==NOPIECE) return 1;
149 if (fr - tr == 1) return 1;
150 if ((fr >= gs->ranks - 1 - gs->pawnDblStep) && (fr - tr == 2) && gs->board[ff][fr-1]==NOPIECE) return 1;
154 if (ff != tf && gs->promoType != 3) { /* Capture ? ([HGM] but not in Shogi) */
155 if ((ff - tf != 1) && (tf - ff != 1)) return 0;
156 if (gs->onMove == WHITE) {
157 if(gs->palace) return (fr >= gs->ranks/2 && fr == tr); // [HGM] XQ promoted pawns
158 if (tr != fr+1) return 0;
159 if ((gs->board[tf][tr] != NOPIECE) && iscolor(gs->board[tf][tr],BLACK))
161 if (gs->ep_possible[0][ff] == 1) {
162 if ((tf==ff+1) && (gs->board[ff+1][fr] == B_PAWN)) return 1;
163 } else if (gs->ep_possible[0][ff] == -1) {
164 if ((tf==ff-1) && (gs->board[ff-1][fr] == B_PAWN)) return 1;
167 if(gs->palace) return (fr < gs->ranks/2 && fr == tr); // [HGM] XQ promoted pawns
168 if (tr != fr-1) return 0;
169 if ((gs->board[tf][tr] != NOPIECE) && iscolor(gs->board[tf][tr],WHITE))
171 if (gs->ep_possible[1][ff] == 1) {
172 if ((tf==ff+1) && (gs->board[ff+1][fr] == W_PAWN)) return 1;
173 } else if (gs->ep_possible[1][ff] == -1) {
174 if ((tf==ff-1) && (gs->board[ff-1][fr] == W_PAWN)) return 1;
181 static int legal_knight_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
198 static int legal_horse_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
205 if (abs(dy) == 1 && gs->board[(ff+tf)/2][fr] == NOPIECE)
209 if (abs(dx) == 1 && gs->board[ff][(fr+tr)/2] == NOPIECE)
215 static int legal_honorablehorse_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
221 if (dy == (gs->onMove == WHITE ? -2 : 2)) {
228 static int legal_bishop_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
252 return 0; /* Not diagonal */
254 return 1; /* One square, ok */
256 for (x = startx, y = starty; count; x += incx, y += incy, count--) {
257 if (gs->board[x][y] != NOPIECE)
263 static int legal_rook_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
269 if (abs(fr - tr) == 1)
278 for (i = start; i <= stop; i++) {
279 if (gs->board[ff][i] != NOPIECE)
283 } else if (fr == tr) {
284 if (abs(ff - tf) == 1)
293 for (i = start; i <= stop; i++) {
294 if (gs->board[i][fr] != NOPIECE)
303 static int legal_cannon_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
316 for (i = start; i <= stop; i++) {
317 if (gs->board[ff][i] != NOPIECE) cnt++;
319 return (cnt == 0 && gs->board[tf][tr] == NOPIECE) ||
320 (cnt == 1 && gs->board[tf][tr] != NOPIECE);
321 } else if (fr == tr) {
329 for (i = start; i <= stop; i++) {
330 if (gs->board[i][fr] != NOPIECE) cnt++;
332 return (cnt == 0 && gs->board[tf][tr] == NOPIECE) ||
333 (cnt == 1 && gs->board[tf][tr] != NOPIECE);
339 static int legal_lance_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
345 if (abs(fr - tr) == 1)
348 if(gs->onMove != WHITE) return 0;
352 if(gs->onMove == WHITE) return 0;
356 for (i = start; i <= stop; i++) {
357 if (gs->board[ff][i] != NOPIECE)
364 static int legal_queen_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
366 return legal_rook_move(gs, ff, fr, tf, tr) || legal_bishop_move(gs, ff, fr, tf, tr);
369 static int legal_cardinal_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
371 return legal_knight_move(gs, ff, fr, tf, tr) || legal_bishop_move(gs, ff, fr, tf, tr);
374 static int legal_marshall_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
376 return legal_rook_move(gs, ff, fr, tf, tr) || legal_knight_move(gs, ff, fr, tf, tr);
379 /* Ckeck, if square (kf,kr) is attacked by enemy piece.
380 * Used in castling from/through check testing.
383 /* new one from soso: */
384 static int is_square_attacked (struct game_state_t *gs, int kf, int kr)
386 struct game_state_t fakeMove;
387 int oldk = gs->onMove == WHITE ? gs->wkmoved : gs->bkmoved;
390 fakeMove.board[oldk][kr] = NOPIECE; // [HGM] castle: this routine is called only when King has not moved
391 fakeMove.board[kf][kr] = KING | fakeMove.onMove;
392 fakeMove.onMove = CToggle (fakeMove.onMove);
393 if (in_check(&fakeMove)) return 1;
398 static int is_square_attacked(struct game_state_t * gs, int kf, int kr)
401 gs->onMove = CToggle(gs->onMove);
403 for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
404 NextPieceLoop(gs->board, &f, &r, gs->onMove, gs->files, gs->ranks);) {
405 if (legal_move(gs, f, r, kf, kr)) {
406 gs->onMove = CToggle(gs->onMove);
410 gs->onMove = CToggle(gs->onMove);
415 static int legal_man_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
417 if (abs(ff - tf) > 1)
419 if (abs(fr - tr) > 1)
424 static int legal_wazir_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
426 if(gs->palace && (tr > gs->palace && tr < gs->ranks - gs->palace ||
427 tf < (gs->files - gs->palace)/2 || tf >= (gs->files + gs->palace)/2))
429 if (abs(ff - tf) == 1 && fr == tr)
431 if (abs(fr - tr) == 1 && ff == tf)
436 static int legal_dababba_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
438 if (abs(ff - tf) == 2 && fr == tr)
440 if (abs(fr - tr) == 2 && ff == tf)
445 static int legal_ferz_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
447 if (abs(ff - tf) != 1)
449 if (abs(fr - tr) != 1)
454 static int legal_mandarin_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
456 if(gs->palace && (tr > gs->palace && tr < gs->ranks - gs->palace ||
457 tf < (gs->files - gs->palace)/2 || tf >= (gs->files + gs->palace)/2))
459 if (abs(ff - tf) != 1)
461 if (abs(fr - tr) != 1)
466 static int legal_alfil_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
468 if (abs(ff - tf) != 2)
470 if (abs(fr - tr) != 2)
475 static int legal_elephant_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
477 if (abs(ff - tf) != 2)
479 if (abs(fr - tr) != 2)
481 if(gs->board[(ff+tf)/2][(fr+tr)/2] != NOPIECE) return 0; // blocked
482 if((tr >= gs->ranks/2) != (fr >= gs->ranks/2)) return 0; // do not cross river
486 static int legal_gold_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
488 return legal_wazir_move(gs, ff, fr, tf, tr) || (abs(ff-tf) == 1 && tr == fr + (gs->onMove==WHITE ? 1 : -1));
491 static int legal_silver_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
493 return legal_ferz_move(gs, ff, fr, tf, tr) || (tf == ff && tr == fr + (gs->onMove==WHITE ? 1 : -1) );
496 static int legal_woody_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
498 return legal_wazir_move(gs, ff, fr, tf, tr) || legal_dababba_move(gs, ff, fr, tf, tr);
501 static int legal_squirrel_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
503 return legal_alfil_move(gs, ff, fr, tf, tr) || legal_dababba_move(gs, ff, fr, tf, tr)
504 || legal_knight_move(gs, ff, fr, tf, tr);
507 static int legal_mastodon_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
509 return legal_man_move(gs, ff, fr, tf, tr) || legal_alfil_move(gs, ff, fr, tf, tr)
510 || legal_dababba_move(gs, ff, fr, tf, tr);
513 static int legal_centaur_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
515 return legal_man_move(gs, ff, fr, tf, tr) || legal_knight_move(gs, ff, fr, tf, tr);
518 static int legal_amazon_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
520 return legal_queen_move(gs, ff, fr, tf, tr) || legal_knight_move(gs, ff, fr, tf, tr);
523 static int legal_dragonking_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
525 return legal_rook_move(gs, ff, fr, tf, tr) || legal_ferz_move(gs, ff, fr, tf, tr);
528 static int legal_dragonhorse_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
530 return legal_bishop_move(gs, ff, fr, tf, tr) || legal_wazir_move(gs, ff, fr, tf, tr);
533 static int legal_modernelephant_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
535 return legal_ferz_move(gs, ff, fr, tf, tr) || legal_alfil_move(gs, ff, fr, tf, tr);
538 static int legal_priestess_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
540 return legal_knight_move(gs, ff, fr, tf, tr) || legal_ferz_move(gs, ff, fr, tf, tr)
541 || legal_alfil_move(gs, ff, fr, tf, tr);
544 static int legal_minister_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
546 return legal_knight_move(gs, ff, fr, tf, tr) || legal_wazir_move(gs, ff, fr, tf, tr)
547 || legal_dababba_move(gs, ff, fr, tf, tr);
550 static int legal_king_move(struct game_state_t * gs, int ff, int fr, int tf, int tr)
554 // [HGM] castle: test first if valid as regular King move; result = 1 or 0
556 result = legal_knight_move(gs, ff, fr, tf, tr);
557 else if(gs->palace) {
558 result = legal_wazir_move(gs, ff, fr, tf, tr);
559 if(!result && ff == tf && piecetype(gs->board[tf][tr]) == KING) { // XQ regicide
560 int i, d = (tr>fr ? 1 : -1);
561 for(i=fr+d; i!=tr; i+=d)
562 if(gs->board[ff][i] != NOPIECE) return 0; // line of sight blocked
566 result = legal_man_move(gs, ff, fr, tf, tr);
569 // [HGM] castle: orthodox legal castlings given as King move return 2
571 if (gs->onMove == WHITE) {
572 /* King side castling */
573 if ((fr == 0) && (tr == 0) && ((ff == gs->files/2) && (tf == gs->files-2) ||
574 gs->drops == 2 && (tf == gs->files/2) && (ff == gs->files-1)) // [HGM] reverse Seirawan gating
575 && (gs->wkmoved >= 0) && (gs->wkrmoved >= 0) && (gs->board[gs->files-3][0] == NOPIECE) &&
576 (gs->board[gs->files-2][0] == NOPIECE) && (gs->board[gs->files-1][0] == W_ROOK) &&
577 (gs->board[gs->files/2+1][0] == NOPIECE) && (!is_square_attacked(gs, gs->files/2+1, 0)) &&
578 (!is_square_attacked(gs, gs->files/2, 0)) && (!is_square_attacked(gs, gs->files-3, 0))) {
581 /* Queen side castling */
582 if ((fr == 0) && (tr == 0) && ((ff == gs->files/2) && (tf == 2) ||
583 gs->drops == 2 && (tf == gs->files/2) && (ff == 0)) // [HGM] reverse Seirawan gating
584 && (gs->wkmoved >= 0) && (gs->wqrmoved >= 0) && (gs->board[3][0] == NOPIECE) &&
585 (gs->board[2][0] == NOPIECE) && (gs->board[1][0] == NOPIECE) &&
586 (gs->board[0][0] == W_ROOK) &&
587 (gs->board[gs->files/2-1][0] == NOPIECE) && (!is_square_attacked(gs, gs->files/2-1, 0)) &&
588 (!is_square_attacked(gs, gs->files/2, 0)) && (!is_square_attacked(gs, 3, 0))) {
592 /* King side castling */
593 if ((fr == gs->ranks-1) && (tr == gs->ranks-1) && ((ff == gs->files/2) && (tf == gs->files-2) ||
594 gs->drops == 2 && (tf == gs->files/2) && (ff == gs->files-1)) // [HGM] reverse Seirawan gating
595 && (gs->bkmoved >= 0) && (gs->bkrmoved >= 0) && (gs->board[gs->files-3][7] == NOPIECE) &&
596 (gs->board[gs->files-2][gs->ranks-1] == NOPIECE) && (gs->board[gs->files-1][gs->ranks-1] == B_ROOK) &&
597 (gs->board[gs->files/2+1][gs->ranks-1] == NOPIECE) && (!is_square_attacked(gs, gs->files/2+1, gs->ranks-1)) &&
598 (!is_square_attacked(gs, gs->files/2, gs->ranks-1)) && (!is_square_attacked(gs, gs->files-3, gs->ranks-1))) {
601 /* Queen side castling */
602 if ((fr == gs->ranks-1) && (tr == gs->ranks-1) && ((ff == gs->files/2) && (tf == 2) ||
603 gs->drops == 2 && (tf == gs->files/2) && (ff == 0)) // [HGM] reverse Seirawan gating
604 && (gs->bkmoved >= 0) && (gs->bqrmoved >= 0) && (gs->board[3][gs->ranks-1] == NOPIECE) &&
605 (gs->board[2][gs->ranks-1] == NOPIECE) && (gs->board[1][gs->ranks-1] == NOPIECE) &&
606 (gs->board[0][gs->ranks-1] == B_ROOK) &&
607 (gs->board[gs->files/2-1][gs->ranks-1] == NOPIECE) && (!is_square_attacked(gs, gs->files/2-1, gs->ranks-1)) &&
608 (!is_square_attacked(gs, gs->files/2, gs->ranks-1)) && (!is_square_attacked(gs, 3, gs->ranks-1))) {
613 return 0; // neither regular King move nor castling
616 static void add_pos(int tof, int tor, int *posf, int *posr, int *numpos)
623 static void possible_pawn_moves(struct game_state_t * gs,
625 int *posf, int *posr, int *numpos)
627 if (gs->onMove == WHITE) {
628 if (gs->board[onf][onr + 1] == NOPIECE || gs->palace || gs->promoType == 3) {
629 add_pos(onf, onr + 1, posf, posr, numpos);
630 if ((onr <= gs->pawnDblStep) && (gs->board[onf][onr + 2] == NOPIECE))
631 add_pos(onf, onr + 2, posf, posr, numpos);
634 if (gs->board[onf - 1][onr + 1] != NOPIECE &&
635 iscolor(gs->board[onf - 1][onr + 1], BLACK) &&
636 !gs->palace && gs->promoType != 3) // no diagonal capture in XQ and Shogi
637 add_pos(onf - 1, onr + 1, posf, posr, numpos);
638 if(gs->palace && onr >= gs->ranks/2 && (gs->board[onf-1][onr] || iscolor(gs->board[onf-1][onr], BLACK)))
639 add_pos(onf - 1, onr, posf, posr, numpos); // XQ promoted pawn
641 if (onf < gs->files-1) {
642 if (gs->board[onf + 1][onr + 1] != NOPIECE &&
643 iscolor(gs->board[onf + 1][onr + 1], BLACK) &&
644 !gs->palace && gs->promoType != 3) // no diagonal capture in XQ and Shogi
645 add_pos(onf + 1, onr + 1, posf, posr, numpos);
646 if(gs->palace && onr >= gs->ranks/2 && (gs->board[onf+1][onr] || iscolor(gs->board[onf+1][onr], BLACK)))
647 add_pos(onf + 1, onr, posf, posr, numpos); // XQ promoted pawn
649 if (gs->ep_possible[0][onf] == -1)
650 add_pos(onf - 1, onr + 1, posf, posr, numpos);
651 if (gs->ep_possible[0][onf] == 1)
652 add_pos(onf + 1, onr + 1, posf, posr, numpos);
654 if (gs->board[onf][onr - 1] == NOPIECE || gs->palace || gs->promoType == 3) {
655 add_pos(onf, onr - 1, posf, posr, numpos);
656 if ((onr >= gs->ranks - gs->pawnDblStep - 1) && (gs->board[onf][onr - 2] == NOPIECE))
657 add_pos(onf, onr - 2, posf, posr, numpos);
660 if (gs->board[onf - 1][onr - 1] != NOPIECE &&
661 iscolor(gs->board[onf - 1][onr - 1], WHITE) &&
662 !gs->palace && gs->promoType != 3) // no diagonal capture in XQ and Shogi
663 add_pos(onf - 1, onr - 1, posf, posr, numpos);
664 if(gs->palace && onr < gs->ranks/2 && !iscolor(gs->board[onf-1][onr], BLACK))
665 add_pos(onf - 1, onr, posf, posr, numpos); // XQ promoted pawn
667 if (onf < gs->files-1) {
668 if (gs->board[onf + 1][onr - 1] != NOPIECE &&
669 iscolor(gs->board[onf + 1][onr - 1], WHITE) &&
670 !gs->palace && gs->promoType != 3) // no diagonal capture in XQ and Shogi
671 add_pos(onf + 1, onr - 1, posf, posr, numpos);
672 if(gs->palace && onr < gs->ranks/2 && !iscolor(gs->board[onf+1][onr], BLACK))
673 add_pos(onf + 1, onr, posf, posr, numpos); // XQ promoted pawn
675 if (gs->ep_possible[1][onf] == -1)
676 add_pos(onf - 1, onr - 1, posf, posr, numpos);
677 if (gs->ep_possible[1][onf] == 1)
678 add_pos(onf + 1, onr - 1, posf, posr, numpos);
682 static void possible_knight_moves(struct game_state_t * gs,
684 int *posf, int *posr, int *numpos)
686 static int knightJumps[8][2] = {{-1, 2}, {1, 2}, {2, -1}, {2, 1},
687 {-1, -2}, {1, -2}, {-2, 1}, {-2, -1}};
691 for (j = 0; j < 8; j++) {
692 f = knightJumps[j][0] + onf;
693 r = knightJumps[j][1] + onr;
694 if ((f < 0) || (f >= gs->files))
696 if ((r < 0) || (r >= gs->ranks))
698 if ((gs->board[f][r] == NOPIECE) ||
699 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
700 add_pos(f, r, posf, posr, numpos);
704 static void possible_horse_moves(struct game_state_t * gs,
706 int *posf, int *posr, int *numpos)
708 static int knightJumps[8][4] = {{-1, 2, 0, 1}, {1, 2, 0, 1}, {2, -1, 1, 0}, {2, 1, 1, 0},
709 {-1, -2, 0, -1}, {1, -2, 0, -1}, {-2, 1, -1, 0}, {-2, -1, -1, 0}};
713 for (j = 0; j < 8; j++) {
714 f = knightJumps[j][0] + onf;
715 r = knightJumps[j][1] + onr;
716 if ((f < 0) || (f >= gs->files))
718 if ((r < 0) || (r >= gs->ranks))
720 if ((gs->board[knightJumps[j][2] + onf][knightJumps[j][3] + onr] == NOPIECE) &&
721 ((gs->board[f][r] == NOPIECE) || (iscolor(gs->board[f][r], CToggle(gs->onMove)))))
722 add_pos(f, r, posf, posr, numpos);
726 static void possible_bishop_moves(struct game_state_t * gs,
728 int *posf, int *posr, int *numpos)
738 if ((f < 0) || (f >= gs->files))
740 if ((r < 0) || (r >= gs->ranks))
742 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
744 add_pos(f, r, posf, posr, numpos);
745 if (gs->board[f][r] != NOPIECE)
754 if ((f < 0) || (f >= gs->files))
756 if ((r < 0) || (r >= gs->ranks))
758 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
760 add_pos(f, r, posf, posr, numpos);
761 if (gs->board[f][r] != NOPIECE)
770 if ((f < 0) || (f >= gs->files))
772 if ((r < 0) || (r >= gs->ranks))
774 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
776 add_pos(f, r, posf, posr, numpos);
777 if (gs->board[f][r] != NOPIECE)
786 if ((f < 0) || (f >= gs->files))
788 if ((r < 0) || (r >= gs->ranks))
790 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
792 add_pos(f, r, posf, posr, numpos);
793 if (gs->board[f][r] != NOPIECE)
798 static void possible_rook_moves(struct game_state_t * gs,
800 int *posf, int *posr, int *numpos)
809 if ((f < 0) || (f >= gs->files))
811 if ((r < 0) || (r >= gs->ranks))
813 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
815 add_pos(f, r, posf, posr, numpos);
816 if (gs->board[f][r] != NOPIECE)
824 if ((f < 0) || (f >= gs->files))
826 if ((r < 0) || (r >= gs->ranks))
828 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
830 add_pos(f, r, posf, posr, numpos);
831 if (gs->board[f][r] != NOPIECE)
839 if ((f < 0) || (f >= gs->files))
841 if ((r < 0) || (r >= gs->ranks))
843 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
845 add_pos(f, r, posf, posr, numpos);
846 if (gs->board[f][r] != NOPIECE)
854 if ((f < 0) || (f >= gs->files))
856 if ((r < 0) || (r >= gs->ranks))
858 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
860 add_pos(f, r, posf, posr, numpos);
861 if (gs->board[f][r] != NOPIECE)
866 static void possible_cannon_moves(struct game_state_t * gs,
868 int *posf, int *posr, int *numpos)
877 if ((f < 0) || (f >= gs->files))
879 if ((r < 0) || (r >= gs->ranks))
881 if ((gs->board[f][r] != NOPIECE) && i++ == 0) continue;
883 add_pos(f, r, posf, posr, numpos); // no hop: non-capt
884 else if(i == 2 && !iscolor(gs->board[f][r], gs->onMove))
885 add_pos(f, r, posf, posr, numpos); // hop: capt
886 if (gs->board[f][r] != NOPIECE)
894 if ((f < 0) || (f >= gs->files))
896 if ((r < 0) || (r >= gs->ranks))
898 if ((gs->board[f][r] != NOPIECE) && i++ == 0) continue;
900 add_pos(f, r, posf, posr, numpos); // no hop: non-capt
901 else if(i == 2 && !iscolor(gs->board[f][r], gs->onMove))
902 add_pos(f, r, posf, posr, numpos); // hop: capt
903 if (gs->board[f][r] != NOPIECE)
911 if ((f < 0) || (f >= gs->files))
913 if ((r < 0) || (r >= gs->ranks))
915 if ((gs->board[f][r] != NOPIECE) && i++ == 0) continue;
917 add_pos(f, r, posf, posr, numpos); // no hop: non-capt
918 else if(i == 2 && !iscolor(gs->board[f][r], gs->onMove))
919 add_pos(f, r, posf, posr, numpos); // hop: capt
920 if (gs->board[f][r] != NOPIECE)
928 if ((f < 0) || (f >= gs->files))
930 if ((r < 0) || (r >= gs->ranks))
932 if ((gs->board[f][r] != NOPIECE) && i++ == 0) continue;
934 add_pos(f, r, posf, posr, numpos); // no hop: non-capt
935 else if(i == 2 && !iscolor(gs->board[f][r], gs->onMove))
936 add_pos(f, r, posf, posr, numpos); // hop: capt
937 if (gs->board[f][r] != NOPIECE)
942 static void possible_lance_moves(struct game_state_t * gs,
944 int *posf, int *posr, int *numpos)
951 for (;gs->onMove == WHITE;) {
953 if ((f < 0) || (f >= gs->files))
955 if ((r < 0) || (r >= gs->ranks))
957 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
959 add_pos(f, r, posf, posr, numpos);
960 if (gs->board[f][r] != NOPIECE)
966 for (;gs->onMove == BLACK;) {
968 if ((f < 0) || (f >= gs->files))
970 if ((r < 0) || (r >= gs->ranks))
972 if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
974 add_pos(f, r, posf, posr, numpos);
975 if (gs->board[f][r] != NOPIECE)
980 static void possible_cardinal_moves(struct game_state_t * gs,
982 int *posf, int *posr, int *numpos)
984 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
985 possible_bishop_moves(gs, onf, onr, posf, posr, numpos);
988 static void possible_marshall_moves(struct game_state_t * gs,
990 int *posf, int *posr, int *numpos)
992 possible_rook_moves(gs, onf, onr, posf, posr, numpos);
993 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
996 static void possible_queen_moves(struct game_state_t * gs,
998 int *posf, int *posr, int *numpos)
1000 possible_rook_moves(gs, onf, onr, posf, posr, numpos);
1001 possible_bishop_moves(gs, onf, onr, posf, posr, numpos);
1004 static void possible_alfil_moves(struct game_state_t * gs,
1006 int *posf, int *posr, int *numpos)
1008 static int kingJumps[4][2] = {{-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
1012 for (j = 0; j < 4; j++) {
1013 f = 2*kingJumps[j][0] + onf;
1014 r = 2*kingJumps[j][1] + onr;
1015 if ((f < 0) || (f >= gs->files))
1017 if ((r < 0) || (r >= gs->ranks))
1019 if ((gs->board[f][r] == NOPIECE) ||
1020 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
1021 add_pos(f, r, posf, posr, numpos);
1025 static void possible_ferz_moves(struct game_state_t * gs,
1027 int *posf, int *posr, int *numpos)
1029 static int kingJumps[4][2] = {{-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
1033 for (j = 0; j < 4; j++) {
1034 f = kingJumps[j][0] + onf;
1035 r = kingJumps[j][1] + onr;
1036 if ((f < 0) || (f >= gs->files))
1038 if ((r < 0) || (r >= gs->ranks))
1040 if ((gs->board[f][r] == NOPIECE) ||
1041 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
1042 add_pos(f, r, posf, posr, numpos);
1046 static void possible_mandarin_moves(struct game_state_t * gs,
1048 int *posf, int *posr, int *numpos)
1050 static int kingJumps[4][2] = {{-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
1054 for (j = 0; j < 4; j++) {
1055 f = kingJumps[j][0] + onf;
1056 r = kingJumps[j][1] + onr;
1057 if ((f < 0) || (f >= gs->files))
1059 if ((r < 0) || (r >= gs->ranks))
1061 if(gs->palace && (r >= gs->palace && r < gs->ranks - gs->palace ||
1062 f < (gs->files - gs->palace)/2 || f >= (gs->files + gs->palace)/2))
1064 if ((gs->board[f][r] == NOPIECE) ||
1065 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
1066 add_pos(f, r, posf, posr, numpos);
1070 static void possible_wazir_moves(struct game_state_t * gs,
1072 int *posf, int *posr, int *numpos)
1074 static int kingJumps[4][2] = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}};
1078 for (j = 0; j < 4; j++) {
1079 f = kingJumps[j][0] + onf;
1080 r = kingJumps[j][1] + onr;
1081 if ((f < 0) || (f >= gs->files))
1083 if ((r < 0) || (r >= gs->ranks))
1085 if(gs->palace && (r >= gs->palace && r < gs->ranks - gs->palace ||
1086 f < (gs->files - gs->palace)/2 || f >= (gs->files + gs->palace)/2))
1088 if ((gs->board[f][r] == NOPIECE) ||
1089 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
1090 add_pos(f, r, posf, posr, numpos);
1094 static void possible_dababba_moves(struct game_state_t * gs,
1096 int *posf, int *posr, int *numpos)
1098 static int kingJumps[4][2] = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}};
1102 for (j = 0; j < 4; j++) {
1103 f = 2*kingJumps[j][0] + onf;
1104 r = 2*kingJumps[j][1] + onr;
1105 if ((f < 0) || (f >= gs->files))
1107 if ((r < 0) || (r >= gs->ranks))
1109 if ((gs->board[f][r] == NOPIECE) ||
1110 (iscolor(gs->board[f][r], CToggle(gs->onMove))))
1111 add_pos(f, r, posf, posr, numpos);
1115 static void possible_man_moves(struct game_state_t * gs,
1117 int *posf, int *posr, int *numpos)
1119 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1120 possible_ferz_moves(gs, onf, onr, posf, posr, numpos);
1123 static void possible_dragonking_moves(struct game_state_t * gs,
1125 int *posf, int *posr, int *numpos)
1127 possible_rook_moves(gs, onf, onr, posf, posr, numpos);
1128 possible_ferz_moves(gs, onf, onr, posf, posr, numpos);
1131 static void possible_dragonhorse_moves(struct game_state_t * gs,
1133 int *posf, int *posr, int *numpos)
1135 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1136 possible_bishop_moves(gs, onf, onr, posf, posr, numpos);
1139 static void possible_centaur_moves(struct game_state_t * gs,
1141 int *posf, int *posr, int *numpos)
1143 possible_man_moves(gs, onf, onr, posf, posr, numpos);
1144 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1147 static void possible_woody_moves(struct game_state_t * gs,
1149 int *posf, int *posr, int *numpos)
1151 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1152 possible_dababba_moves(gs, onf, onr, posf, posr, numpos);
1155 static void possible_squirrel_moves(struct game_state_t * gs,
1157 int *posf, int *posr, int *numpos)
1159 possible_alfil_moves(gs, onf, onr, posf, posr, numpos);
1160 possible_dababba_moves(gs, onf, onr, posf, posr, numpos);
1161 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1164 static void possible_mastodon_moves(struct game_state_t * gs,
1166 int *posf, int *posr, int *numpos)
1168 possible_man_moves(gs, onf, onr, posf, posr, numpos);
1169 possible_alfil_moves(gs, onf, onr, posf, posr, numpos);
1170 possible_dababba_moves(gs, onf, onr, posf, posr, numpos);
1173 static void possible_amazon_moves(struct game_state_t * gs,
1175 int *posf, int *posr, int *numpos)
1177 possible_queen_moves(gs, onf, onr, posf, posr, numpos);
1178 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1181 static void possible_modernelephant_moves(struct game_state_t * gs,
1183 int *posf, int *posr, int *numpos)
1185 possible_ferz_moves(gs, onf, onr, posf, posr, numpos);
1186 possible_alfil_moves(gs, onf, onr, posf, posr, numpos);
1189 static void possible_priestess_moves(struct game_state_t * gs,
1191 int *posf, int *posr, int *numpos)
1193 possible_ferz_moves(gs, onf, onr, posf, posr, numpos);
1194 possible_alfil_moves(gs, onf, onr, posf, posr, numpos);
1195 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1198 static void possible_minister_moves(struct game_state_t * gs,
1200 int *posf, int *posr, int *numpos)
1202 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1203 possible_dababba_moves(gs, onf, onr, posf, posr, numpos);
1204 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1207 static void possible_gold_moves(struct game_state_t * gs,
1209 int *posf, int *posr, int *numpos)
1211 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1212 if(gs->onMove == WHITE) {
1213 if(onr < gs->ranks-1)
1214 if(onf > 0 && !iscolor(gs->board[onf-1][onr+1], WHITE))
1215 add_pos(onf-1, onr+1, posf, posr, numpos);
1216 if(onf < gs->files-1 && !iscolor(gs->board[onf+1][onr+1], WHITE))
1217 add_pos(onf+1, onr+1, posf, posr, numpos);
1220 if(onf > 0 && !iscolor(gs->board[onf-1][onr-1], BLACK))
1221 add_pos(onf-1, onr-1, posf, posr, numpos);
1222 if(onf < gs->files-1 && !iscolor(gs->board[onf+1][onr-1], BLACK))
1223 add_pos(onf+1, onr-1, posf, posr, numpos);
1227 static void possible_silver_moves(struct game_state_t * gs,
1229 int *posf, int *posr, int *numpos)
1231 possible_ferz_moves(gs, onf, onr, posf, posr, numpos);
1232 if(gs->onMove == WHITE) {
1233 if(onr < gs->ranks-1 && !iscolor(gs->board[onf][onr+1], WHITE))
1234 add_pos(onf, onr+1, posf, posr, numpos);
1236 if(onr > 0 && !iscolor(gs->board[onf][onr-1], BLACK))
1237 add_pos(onf, onr-1, posf, posr, numpos);
1241 static void possible_honorablehorse_moves(struct game_state_t * gs,
1243 int *posf, int *posr, int *numpos)
1245 int f, r = onr + (gs->onMove == WHITE ? 2 : -2);
1247 if(r < 0 || r >= gs->ranks) return;
1249 if ((gs->board[onf-1][r] == NOPIECE) ||
1250 (iscolor(gs->board[onf-1][r], CToggle(gs->onMove))))
1251 add_pos(onf - 1, r, posf, posr, numpos);
1253 if(onf < gs->files - 1) {
1254 if ((gs->board[onf+1][r] == NOPIECE) ||
1255 (iscolor(gs->board[onf+1][r], CToggle(gs->onMove))))
1256 add_pos(onf + 1, r, posf, posr, numpos);
1260 static void possible_king_moves(struct game_state_t * gs,
1262 int *posf, int *posr, int *numpos)
1265 possible_knight_moves(gs, onf, onr, posf, posr, numpos);
1267 possible_wazir_moves(gs, onf, onr, posf, posr, numpos);
1269 possible_man_moves(gs, onf, onr, posf, posr, numpos);
1272 static void possible_elephant_moves(struct game_state_t * gs,
1274 int *posf, int *posr, int *numpos)
1276 static int kingJumps[4][2] = {{-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
1280 for (j = 0; j < 4; j++) {
1281 f = 2*kingJumps[j][0] + onf;
1282 r = 2*kingJumps[j][1] + onr;
1283 if ((f < 0) || (f >= gs->files))
1285 if ((r < 0) || (r >= gs->ranks))
1287 if ((gs->board[(f+onf)/2][(r+onr)/2] == NOPIECE) && ((gs->board[f][r] == NOPIECE) ||
1288 (iscolor(gs->board[f][r], CToggle(gs->onMove)))))
1289 add_pos(f, r, posf, posr, numpos);
1293 /* Doesn't check for check */
1294 int legal_move(struct game_state_t * gs,
1295 int fFile, int fRank,
1296 int tFile, int tRank)
1298 int move_piece, victim;
1301 if (fFile == ALG_DROP) {
1303 if(gs->drops != 1) return 0; // [HGM] variants: no drops in this variant
1304 if (move_piece == KING)
1306 if (gs->holding[gs->onMove==WHITE ? 0 : 1][move_piece-1] == 0)
1308 if (gs->board[tFile][tRank] != NOPIECE)
1310 if (gs->promoType == 3) { // Shogi
1312 switch(move_piece) {
1313 case PAWN: // check for own Pawn in same file
1314 for(r=0; r<gs->ranks; r++) if(gs->board[tFile][r] == (gs->onMove|PAWN)) return 0;
1315 case LANCE: // Pawns and Lances not on last rank
1316 if(gs->onMove == WHITE && tRank >= gs->ranks-1) return 0;
1317 if(gs->onMove == BLACK && tRank < 1) return 0;
1319 case HONORABLEHORSE: // Knights at least two ranks from edge
1320 if(gs->onMove == WHITE && tRank >= gs->ranks-2) return 0;
1321 if(gs->onMove == BLACK && tRank < 2) return 0;
1325 if (move_piece == PAWN && (tRank == 0 || tRank == gs->ranks-1))
1328 } else if(fFile == ALG_CASTLE) {
1329 // [HGM] castle: this code can handle any type of free castling
1330 // it does not check if Rook and King from squares correspond to the rights, as the
1331 // user never enters such squares, but they are copied from the rights on entering o-o-o
1332 int backRank, kRook, qRook, fKing, leftEmpty, rightEmpty, leftCheck, rightCheck, f;
1333 if(!gs->castlingStyle) return 0; // no castling in this variant
1334 if(gs->onMove == WHITE) {
1335 if(gs->wkmoved < 0) return 0; // King moved
1336 fKing = gs->wkmoved;
1338 kRook = gs->wkrmoved;
1339 qRook = gs->wqrmoved;
1341 if(gs->bkmoved < 0) return 0; // King moved
1342 fKing = gs->bkmoved;
1343 backRank = gs->ranks-1;
1344 kRook = gs->bkrmoved;
1345 qRook = gs->bqrmoved;
1347 if((tRank > tFile ? qRook : kRook) < 0) return 0; // Rook moved
1348 // here we verified rights do exist, so from squares (fRank and fKing) must be valid
1349 if(gs->board[fRank][backRank] != (ROOK | gs->onMove) ) return 0; // only with own Rook
1350 if(gs->board[fKing][backRank] != (KING | gs->onMove) ) return 0; // only with own King
1352 // by now we know that K and R are in correct position, and still have rights
1353 if(tRank > tFile) { // R ends right of K: q-side
1354 leftEmpty = fRank < tFile ? fRank+1 : tFile+1;
1355 rightEmpty = tRank < fKing ? fKing-1 : tRank-1;
1357 leftEmpty = tRank < fKing ? tRank+1 : fKing+1;
1358 rightEmpty = fRank < tFile ? fRank-1 : tFile-1;
1360 for(f=leftEmpty; f<=rightEmpty; f++) // check if other pieces block castling
1361 if(f != fRank && f != fKing && gs->board[f][backRank] != NOPIECE) return 0;
1363 leftCheck = fKing < tFile ? fKing : tFile+1;
1364 rightCheck = fKing < tFile ? tFile-1 : fKing;
1365 for(f=leftCheck; f<=rightCheck; f++) // check if King passes attacked square or was in check
1366 if(is_square_attacked(gs, f, backRank)) return 0;
1368 return 1; // passed all tests
1370 move_piece = piecetype(gs->board[fFile][fRank]);
1372 if (gs->board[fFile][fRank] == NOPIECE)
1374 if (!iscolor(gs->board[fFile][fRank], gs->onMove)) /* Wrong color */
1376 if (((victim = gs->board[tFile][tRank]) != NOPIECE) &&
1377 iscolor(gs->board[tFile][tRank], gs->onMove)) {
1378 if(piecetype(move_piece) == KING && piecetype(victim) == ROOK) { // [HGM] could be FRC castling
1380 if(gs->drops== 2 && piecetype(move_piece) == ROOK && piecetype(victim) == KING) { // [HGM] could be Seirawan reverse gating
1381 return legal_king_move(gs, fFile, fRank, tFile, tRank);
1383 return 0; /* Can't capture own */
1385 if ((fFile == tFile) && (fRank == tRank)) /* Same square */
1387 switch (move_piece) {
1389 legal = legal_pawn_move(gs, fFile, fRank, tFile, tRank);
1392 legal = legal_knight_move(gs, fFile, fRank, tFile, tRank);
1395 legal = legal_bishop_move(gs, fFile, fRank, tFile, tRank);
1398 legal = legal_rook_move(gs, fFile, fRank, tFile, tRank);
1403 legal = legal_cardinal_move(gs, fFile, fRank, tFile, tRank);
1408 legal = legal_marshall_move(gs, fFile, fRank, tFile, tRank);
1412 legal = legal_man_move(gs, fFile, fRank, tFile, tRank);
1415 legal = legal_queen_move(gs, fFile, fRank, tFile, tRank);
1418 legal = legal_elephant_move(gs, fFile, fRank, tFile, tRank);
1421 legal = legal_amazon_move(gs, fFile, fRank, tFile, tRank);
1424 legal = legal_woody_move(gs, fFile, fRank, tFile, tRank);
1427 legal = legal_squirrel_move(gs, fFile, fRank, tFile, tRank);
1430 legal = legal_mastodon_move(gs, fFile, fRank, tFile, tRank);
1433 legal = legal_centaur_move(gs, fFile, fRank, tFile, tRank);
1436 legal = legal_horse_move(gs, fFile, fRank, tFile, tRank);
1440 legal = legal_ferz_move(gs, fFile, fRank, tFile, tRank);
1443 legal = legal_mandarin_move(gs, fFile, fRank, tFile, tRank);
1446 legal = legal_wazir_move(gs, fFile, fRank, tFile, tRank);
1450 legal = legal_alfil_move(gs, fFile, fRank, tFile, tRank);
1452 case MODERNELEPHANT:
1453 legal = legal_modernelephant_move(gs, fFile, fRank, tFile, tRank);
1456 legal = legal_priestess_move(gs, fFile, fRank, tFile, tRank);
1459 legal = legal_minister_move(gs, fFile, fRank, tFile, tRank);
1462 legal = legal_silver_move(gs, fFile, fRank, tFile, tRank);
1465 legal = legal_gold_move(gs, fFile, fRank, tFile, tRank);
1468 legal = legal_lance_move(gs, fFile, fRank, tFile, tRank);
1471 legal = legal_cannon_move(gs, fFile, fRank, tFile, tRank);
1474 legal = legal_dragonhorse_move(gs, fFile, fRank, tFile, tRank);
1477 legal = legal_dragonking_move(gs, fFile, fRank, tFile, tRank);
1479 case HONORABLEHORSE:
1480 legal = legal_honorablehorse_move(gs, fFile, fRank, tFile, tRank);
1483 legal = legal_king_move(gs, fFile, fRank, tFile, tRank);
1492 #define DROP_CHAR '@'
1494 /* This fills in the rest of the mt structure once it is determined that
1495 * the move is legal. Returns MOVE_ILLEGAL if move leaves you in check */
1496 static int move_calculate(struct game_state_t * gs, struct move_t * mt, int promote)
1498 struct game_state_t fakeMove;
1499 int gating = 0, stm;
1501 mt->pieceCaptured = gs->board[mt->toFile][mt->toRank];
1502 mt->enPassant = 0; /* Don't know yet, let execute move take care
1504 if (mt->fromFile == ALG_DROP) {
1505 mt->piecePromotionTo = NOPIECE;
1506 sprintf(mt->moveString, "%s/%c%c-%c%d",
1507 wpstring[mt->fromRank],
1508 DROP_CHAR, DROP_CHAR,
1509 mt->toFile + 'a', mt->toRank + 1 - (gs->ranks>9));
1510 } else if(mt->fromFile == ALG_CASTLE) {
1511 // [HGM] castle: generalized castling, fr and tr give from and to file of Rook.
1512 sprintf(mt->moveString, mt->toRank > mt->toFile ? "o-o-o" : "o-o");
1513 if(gs->drops == 2 && promote && gs->holding[gs->onMove == BLACK][abs(promote)-1]) { // promote can be flipped (reverse gating kludge)
1514 int c = gs->onMove == WHITE ? 0 : gs->ranks-1;
1515 mt->piecePromotionTo = promote; gating = 1;
1516 if(promote < 0) sprintf(mt->moveString, "R/%c%d-e%d", mt->fromRank + 'a', c, c); // use RxK notation for Rook-square gatings
1519 stm = colorval(gs->board[mt->fromFile][mt->fromRank]);
1520 if(gs->promoType == 3) { // Shogi-style promotions: not just Pawns, but many pieces can promote
1521 int piece = gs->board[mt->fromFile][mt->fromRank];
1522 mt->piecePromotionTo = NOPIECE;
1523 if(colorval(piece) == WHITE && mt->fromRank < gs->ranks - gs->ranks/3
1524 && mt->toRank < gs->ranks - gs->ranks/3 ||
1525 colorval(piece) == BLACK && mt->fromRank >= gs->ranks/3
1526 && mt->toRank >= gs->ranks/3 )
1527 promote = NOPIECE; // suppress promotion outside zone
1528 if(promote) { // promotion piece determined by original, no matter what was requested
1529 switch(piecetype(piece)) {
1532 case HONORABLEHORSE:
1534 promote = GOLD; break;
1536 promote = DRAGONHORSE; break;
1538 promote = DRAGONKING; break;
1539 default: promote = NOPIECE; // not a promotion
1542 switch(piecetype(piece)) { // force mandatory promotions
1543 case HONORABLEHORSE:
1544 if(mt->toRank == 1 || mt->toRank == gs->files-2) promote = GOLD;
1547 if(mt->toRank == 0 || mt->toRank == gs->files-1) promote = GOLD;
1550 if(promote) mt->piecePromotionTo = promote | (colorval(gs->board[mt->fromFile][mt->fromRank]));
1552 if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == PAWN) &&
1553 !gs->palace && // [HGM] XQ: no promotions in xiangqi
1554 ((mt->toRank < gs->promoZone) || (mt->toRank >= gs->ranks - gs->promoZone))) {
1555 if(!promote && (mt->toRank == 0 || mt->toRank == gs->ranks-1)) { // promotion obligatory, but not specified
1556 if(gs->promoType != 2) promote = QUEEN; else { // choose a default
1557 for(promote=PIECES-1; promote>PAWN; promote--) if(gs->holding[stm == BLACK][promote-1]) break;
1558 if(promote == PAWN) return MOVE_ILLEGAL; // nothing available
1560 } // if not obligatory, we defer unless promotion was explicitly specified!
1561 if(!gs->pawnDblStep && promote == PRINCESS) promote = MAN2;
1562 if(!gs->pawnDblStep && promote != FERZ2 && promote != MAN2) promote = FERZ; // [HGM] kludge to recognize shatranj
1563 // non-promotion can still be an option for deeper promotion zones
1564 mt->piecePromotionTo = promote ? (promote | stm) : NOPIECE;
1565 if(promote && gs->promoType == 2 && !gs->holding[stm == BLACK][promote-1]) return MOVE_ILLEGAL; // unavailable piece specified
1566 } else if(gs->drops == 2 && promote && mt->fromRank == (stm == WHITE ? 0 : gs->ranks-1)) { // [HGM] Seirawan-style gating
1567 int i; struct game *g = &game_globals.garray[gs->gameNum];
1568 if(!gs->holding[stm == BLACK][promote-1]) return MOVE_ILLEGAL; // unavailable piece specified
1569 // now we must test virginity of the moved piece. Yegh!
1570 for (i = g->numHalfMoves-1; i >= 0; i--) {
1571 if (g->moveList[i].fromFile == mt->fromFile && g->moveList[i].fromRank == mt->fromRank ||
1572 g->moveList[i].toFile == mt->fromFile && g->moveList[i].toRank == mt->fromRank ||
1573 g->moveList[i].fromFile == ALG_CASTLE && (gs->onMove == WHITE ? 0 : gs->ranks-1) == mt->fromRank &&
1574 (g->moveList[i].fromRank == mt->fromFile || gs->files>>1 == mt->fromFile )) return MOVE_ILLEGAL;
1576 mt->piecePromotionTo = promote; // gating OK
1577 gating = 1; // remember we did it for check test
1579 mt->piecePromotionTo = NOPIECE;
1581 if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == PAWN) &&
1582 ((mt->fromRank - mt->toRank == 2) || (mt->toRank - mt->fromRank == 2))) {
1583 mt->doublePawn = mt->fromFile;
1585 mt->doublePawn = -1;
1588 if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == KING) &&
1589 (mt->fromFile == gs->files/2) && (mt->toFile == 2) &&
1590 mt->fromRank == mt->toRank) {
1591 sprintf(mt->moveString, "o-o-o");
1592 } else if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == KING) &&
1593 (mt->fromFile == gs->files/2) && (mt->toFile == gs->files-2) &&
1594 mt->fromRank == mt->toRank) {
1595 sprintf(mt->moveString, "o-o");
1600 sprintf(mt->moveString, "%s/%c%d-%c%d",
1601 wpstring[piecetype(gs->board[mt->fromFile][mt->fromRank])],
1602 mt->fromFile + 'a', mt->fromRank + 1 - (gs->ranks>9),
1603 mt->toFile + 'a', mt->toRank + 1 - (gs->ranks>9));
1606 /* Replace this with an algabraic de-parser */
1608 sprintf(mt->algString, alg_unparse(gs, mt));
1610 /* Calculates enPassant also */
1611 execute_move(&fakeMove, mt, 0);
1612 if(gating) fakeMove.board[mt->fromFile][mt->fromRank] = NOPIECE; // [HGM] gating is only legal if non-gating move was (weird, but true)
1614 /* Does making this move leave ME in check? */
1615 if (in_check(&fakeMove))
1616 return MOVE_ILLEGAL;
1617 /* IanO: bughouse variants: drop cannot be check/checkmate */
1622 int legal_andcheck_move(struct game_state_t * gs,
1623 int fFile, int fRank,
1624 int tFile, int tRank)
1628 if (!legal_move(gs, fFile, fRank, tFile, tRank))
1630 mt.color = gs->onMove;
1631 mt.fromFile = fFile;
1632 mt.fromRank = fRank;
1635 /* This should take into account a pawn promoting to another piece */
1636 if (move_calculate(gs, &mt, NOPIECE) == MOVE_OK)
1642 /* in_check: checks if the side that is NOT about to move is in check
1644 int in_check(struct game_state_t * gs)
1647 int kf = -1, kr = -1;
1650 if (gs->onMove == WHITE) {
1651 for (f = 0; f < gs->files && kf < 0; f++)
1652 for (r = 0; r < gs->ranks && kf < 0; r++)
1653 if (gs->board[f][r] == B_KING) {
1658 for (f = 0; f < gs->files && kf < 0; f++)
1659 for (r = 0; r < gs->ranks && kf < 0; r++)
1660 if (gs->board[f][r] == W_KING) {
1666 d_printf( "CHESSD: Error game with no king!\n");
1669 for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
1670 NextPieceLoop(gs->board, &f, &r, gs->onMove, gs->files, gs->ranks);) {
1671 if (legal_move(gs, f, r, kf, kr)) { /* In Check? */
1678 int has_legal_move(struct game_state_t * gs)
1683 int possiblef[500], possibler[500];
1684 int numpossible = 0;
1686 for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
1687 NextPieceLoop(gs->board, &f, &r, gs->onMove, gs->files, gs->ranks);) {
1688 switch (piecetype(gs->board[f][r])) {
1690 possible_pawn_moves(gs, f, r, possiblef, possibler, &numpossible);
1693 possible_knight_moves(gs, f, r, possiblef, possibler, &numpossible);
1696 possible_bishop_moves(gs, f, r, possiblef, possibler, &numpossible);
1699 possible_rook_moves(gs, f, r, possiblef, possibler, &numpossible);
1704 possible_cardinal_moves(gs, f, r, possiblef, possibler, &numpossible);
1709 possible_marshall_moves(gs, f, r, possiblef, possibler, &numpossible);
1713 possible_man_moves(gs, f, r, possiblef, possibler, &numpossible);
1716 possible_queen_moves(gs, f, r, possiblef, possibler, &numpossible);
1719 possible_elephant_moves(gs, f, r, possiblef, possibler, &numpossible);
1722 possible_amazon_moves(gs, f, r, possiblef, possibler, &numpossible);
1725 possible_woody_moves(gs, f, r, possiblef, possibler, &numpossible);
1728 possible_squirrel_moves(gs, f, r, possiblef, possibler, &numpossible);
1731 possible_mastodon_moves(gs, f, r, possiblef, possibler, &numpossible);
1734 possible_centaur_moves(gs, f, r, possiblef, possibler, &numpossible);
1737 possible_horse_moves(gs, f, r, possiblef, possibler, &numpossible);
1741 possible_ferz_moves(gs, f, r, possiblef, possibler, &numpossible);
1744 possible_mandarin_moves(gs, f, r, possiblef, possibler, &numpossible);
1747 possible_wazir_moves(gs, f, r, possiblef, possibler, &numpossible);
1751 possible_alfil_moves(gs, f, r, possiblef, possibler, &numpossible);
1753 case MODERNELEPHANT:
1754 possible_modernelephant_moves(gs, f, r, possiblef, possibler, &numpossible);
1757 possible_priestess_moves(gs, f, r, possiblef, possibler, &numpossible);
1760 possible_minister_moves(gs, f, r, possiblef, possibler, &numpossible);
1763 possible_silver_moves(gs, f, r, possiblef, possibler, &numpossible);
1766 possible_gold_moves(gs, f, r, possiblef, possibler, &numpossible);
1769 possible_cannon_moves(gs, f, r, possiblef, possibler, &numpossible);
1772 possible_lance_moves(gs, f, r, possiblef, possibler, &numpossible);
1775 possible_dragonhorse_moves(gs, f, r, possiblef, possibler, &numpossible);
1778 possible_dragonking_moves(gs, f, r, possiblef, possibler, &numpossible);
1780 case HONORABLEHORSE:
1781 possible_honorablehorse_moves(gs, f, r, possiblef, possibler, &numpossible);
1786 possible_king_moves(gs, f, r, possiblef, possibler, &numpossible);
1789 if (numpossible >= 500) {
1790 d_printf( "CHESSD: Possible move overrun\n");
1792 for (i = 0; i < numpossible; i++)
1793 if (legal_andcheck_move(gs, f, r, possiblef[i], possibler[i])) {
1798 /* IanO: if we got here, then kf and kr must be set */
1799 if (gs->gameNum >=0 && game_globals.garray[gs->gameNum].link >= 0
1800 || gs->holdings) { // [HGM] zh: also in 2-player games with drops
1801 /* bughouse: potential drops as check interpositions */
1802 gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]++;
1803 for (f=kf-1; f<=kf+1; f++) for (r=kr-1; r<=kr+1; r++) {
1804 if (f>=0 && f<gs->files && r>=0 && r<gs->ranks && gs->board[f][r] == NOPIECE) {
1805 /* try a drop next to the king */
1806 if (legal_andcheck_move(gs, ALG_DROP, QUEEN, f, r)) {
1807 gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]--;
1808 // OK, so we have an interposing drop. But do we have something to drop?
1809 if(game_globals.garray[gs->gameNum].link < 0) {
1810 // we have no partner, so we must have something to drop now
1811 for(i=QUEEN; i>=PAWN; i--)
1812 if (legal_andcheck_move(gs, ALG_DROP, i, f, r)) return 1;
1819 gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]--;
1825 /* This will end up being a very complicated function */
1826 int parse_move(char *mstr, struct game_state_t * gs, struct move_t * mt, int promote)
1828 int type = is_move(mstr);
1829 int result, flipflag = 1;
1831 mt->piecePromotionTo = NOPIECE;
1832 mt->color = gs->onMove;
1835 return MOVE_ILLEGAL;
1838 mt->fromFile = mstr[0] - 'a';
1839 mt->fromRank = mstr[1] - '1' + (gs->ranks>9);
1840 mt->toFile = mstr[2] - 'a';
1841 mt->toRank = mstr[3] - '1' + (gs->ranks>9);
1844 mt->fromFile = mstr[0] - 'a';
1845 mt->fromRank = mstr[1] - '1' + (gs->ranks>9);
1846 mt->toFile = mstr[3] - 'a';
1847 mt->toRank = mstr[4] - '1' + (gs->ranks>9);
1851 mt->fromFile = gs->files/2;
1852 mt->toFile = gs->files-2;
1853 if (gs->onMove == WHITE) {
1857 mt->fromRank = gs->ranks-1;
1858 mt->toRank = gs->ranks-1;
1862 // [HGM] castle: for now always assume Fischer-type castling (of which normal castling is a special case).
1863 mt->fromFile = ALG_CASTLE;
1864 mt->toFile = gs->files-2;
1865 mt->fromRank = gs->onMove == WHITE ? gs->wkrmoved : gs->bkrmoved;
1866 mt->toRank = mt->toFile-1; // R next to K
1870 mt->fromFile = gs->files/2;
1872 if (gs->onMove == WHITE) {
1876 mt->fromRank = gs->ranks-1;
1877 mt->toRank = gs->ranks-1;
1881 mt->fromFile = ALG_CASTLE;
1883 mt->fromRank = gs->onMove == WHITE ? gs->wqrmoved : gs->bqrmoved;
1884 mt->toRank = mt->toFile+1;
1887 /* Fills in the mt structure */
1888 if ((result = alg_parse_move(mstr, gs, mt)) != MOVE_OK)
1892 return MOVE_ILLEGAL;
1895 if((mt->fromRank >= gs->ranks || mt->fromRank < 0 || mt->fromFile >= gs->files) &&
1896 mt->fromFile != ALG_DROP && mt->fromFile != ALG_CASTLE
1897 || mt->toRank < 0 || mt->toRank >= gs->ranks || mt->toFile >= gs->files)
1898 return MOVE_ILLEGAL; // [HGM] make sure move stays on board
1900 if (!(result = legal_move(gs, mt->fromFile, mt->fromRank, mt->toFile, mt->toRank)))
1901 return MOVE_ILLEGAL;
1903 if(result == 2) { // [HGM] castle: orthodox castling was given as King move; convert it to new format
1904 int ff=mt->fromFile, tf=mt->toFile;
1905 if(piecetype(gs->board[tf][mt->toRank]) == KING) { // [HGM] RxK notation
1906 mt->fromFile = tf; mt->toFile = ff > tf ? gs->files-2 : 2; // correct to coventional
1907 flipflag = -1; // kludge: flip gated piece
1909 if(mt->fromFile - mt->toFile > 1) { // Q-side
1911 mt->toRank = mt->toFile+1;
1912 } else if(mt->toFile - mt->fromFile > 1) { // K-side
1913 mt->fromRank = gs->files-1;
1914 mt->toRank = mt->toFile-1;
1916 mt->fromFile = ALG_CASTLE;
1919 if (mt->piecePromotionTo != NOPIECE) {
1920 promote = piecetype(mt->piecePromotionTo);
1921 } else if (promote != NOPIECE) { // [HGM] promotion on long algebraic move; correct ambiguous types for variant
1922 if(gs->promoType == 3 && promote == MASTODON) promote = GOLD;
1923 if(gs->drops == 2 && promote == EMPRESS) promote = SELEPHANT;
1924 if(gs->drops == 2 && promote == DRAGONHORSE) promote = HAWK;
1927 return move_calculate(gs, mt, promote*flipflag);
1930 /* Returns MOVE_OK, MOVE_NOMATERIAL, MOVE_CHECKMATE, or MOVE_STALEMATE */
1931 /* check_game_status prevents recursion */
1932 int execute_move(struct game_state_t * gs, struct move_t * mt, int check_game_status)
1936 int i, j, foobar, wCnt, bCnt, king, rook;
1938 if (mt->fromFile == ALG_DROP) {
1939 movedPiece = mt->fromRank;
1940 tookPiece = NOPIECE;
1941 gs->holding[gs->onMove==WHITE ? 0 : 1][movedPiece-1]--;
1942 gs->board[mt->toFile][mt->toRank] = movedPiece | gs->onMove;
1943 if (gs->gameNum >= 0)
1944 gs->lastIrreversable = game_globals.garray[gs->gameNum].numHalfMoves;
1945 } else if(mt->fromFile == ALG_CASTLE) {
1946 int backRank, fKing;
1947 // [HGM] castle: perform castling
1948 if(gs->onMove == WHITE) {
1950 fKing = gs->wkmoved;
1951 gs->wkmoved = -gs->wkmoved-2;
1953 backRank = gs->ranks-1;
1954 fKing = gs->bkmoved;
1955 gs->bkmoved = -gs->bkmoved-2;
1957 // move Rook & King, in a way that is resistant to ending where they started (for FRC!)
1958 rook = gs->board[mt->fromRank][backRank]; // first remember
1959 king = gs->board[fKing][backRank];
1960 gs->board[mt->fromRank][backRank] = NOPIECE; // then erase
1961 gs->board[fKing][backRank] = NOPIECE;
1962 gs->board[mt->toRank][backRank] = rook; // then put back
1963 gs->board[mt->toFile][backRank] = king;
1964 if(gs->drops == 2 && mt->piecePromotionTo != NOPIECE) { // [HGM] Seirawan-style gating
1965 if(mt->piecePromotionTo > 0)
1966 gs->board[fKing][backRank] = mt->piecePromotionTo | gs->onMove; // gate on King square
1968 gs->board[mt->fromRank][backRank] = -mt->piecePromotionTo | gs->onMove; // gate on Rook square
1969 gs->holding[gs->onMove==WHITE ? 0 : 1][abs(mt->piecePromotionTo)-1]--; // remove gated piece from holdings
1972 movedPiece = gs->board[mt->fromFile][mt->fromRank];
1973 tookPiece = gs->board[mt->toFile][mt->toRank];
1974 if(gs->drops == 2 && mt->piecePromotionTo != NOPIECE && piecetype(movedPiece) != PAWN) { // [HGM] Seirawan-style gating
1975 gs->board[mt->toFile][mt->toRank] = gs->board[mt->fromFile][mt->fromRank];
1976 gs->board[mt->fromFile][mt->fromRank] = mt->piecePromotionTo | gs->onMove;;
1977 gs->holding[gs->onMove==WHITE ? 0 : 1][mt->piecePromotionTo-1]--; // remove gated piece from holdings
1979 if (mt->piecePromotionTo == NOPIECE) {
1980 gs->board[mt->toFile][mt->toRank] = gs->board[mt->fromFile][mt->fromRank];
1982 gs->board[mt->toFile][mt->toRank] = mt->piecePromotionTo | gs->onMove;
1983 if(gs->promoType == 2) gs->holding[gs->onMove][mt->piecePromotionTo-1]--;
1985 gs->board[mt->fromFile][mt->fromRank] = NOPIECE;
1987 /* Check if irreversable */
1988 if ((piecetype(movedPiece) == PAWN) && (mt->fromRank != mt->toRank) // [HGM] XQ: sideway Pawn move reversible!
1989 || (tookPiece != NOPIECE)) {
1990 if (gs->gameNum >= 0)
1991 gs->lastIrreversable = game_globals.garray[gs->gameNum].numHalfMoves;
1993 /* Check if this move is en-passant */
1994 if ((piecetype(movedPiece) == PAWN) && (mt->fromFile != mt->toFile) &&
1995 (tookPiece == NOPIECE) && !gs->palace) { // [HGM] XQ: no e.p. in sideway xiangqi moves
1996 if (gs->onMove == WHITE) {
1997 mt->pieceCaptured = B_PAWN;
1999 mt->pieceCaptured = W_PAWN;
2001 if (mt->fromFile > mt->toFile) {
2006 gs->board[mt->toFile][mt->fromRank] = NOPIECE;
2008 /* Check en-passant flags for next moves */
2009 for (i = 0; i < gs->files; i++) {
2010 gs->ep_possible[0][i] = 0;
2011 gs->ep_possible[1][i] = 0;
2013 /* Added by Sparky 3/16/95
2015 From soso@Viktoria.drp.fmph.uniba.sk Thu Mar 16 13:08:51 1995
2016 Subject: Re: To DAV: enpassant prob. again
2017 To: chess@caissa.onenet.net (ICS)
2018 Date: Thu, 16 Mar 1995 20:06:20 +0100 (MET)
2021 There was bug in other part of code:
2023 movecheck.c , line about 800:
2025 if (gs->onMove == WHITE) {
2026 if ((mt->toFile+1 < 7 ) .... should be : (mt->toFile < 7 ) }
2029 if ((piecetype(movedPiece) == PAWN) &&
2030 ((mt->fromRank == mt->toRank + 2) || (mt->fromRank + 2 == mt->toRank))) {
2031 /* Should turn on enpassent flag if possible */
2032 if (gs->onMove == WHITE) {
2033 if ((mt->toFile < gs->files-1) && gs->board[mt->toFile + 1][mt->toRank] == B_PAWN) {
2034 gs->ep_possible[1][mt->toFile + 1] = -1;
2036 if ((mt->toFile - 1 >= 0) && gs->board[mt->toFile - 1][mt->toRank] == B_PAWN) {
2037 gs->ep_possible[1][mt->toFile - 1] = 1;
2040 if ((mt->toFile < gs->files-1) && gs->board[mt->toFile + 1][mt->toRank] == W_PAWN) {
2041 gs->ep_possible[0][mt->toFile + 1] = -1;
2043 if ((mt->toFile - 1 >= 0) && gs->board[mt->toFile - 1][mt->toRank] == W_PAWN) {
2044 gs->ep_possible[0][mt->toFile - 1] = 1;
2048 if ((piecetype(movedPiece) == ROOK) && (mt->fromRank == 0) && (gs->onMove == WHITE)) {
2049 if (mt->fromFile == gs->wqrmoved) // [HGM] castle: flip w.r.t. -1 to remember original
2050 gs->wqrmoved = -gs->wqrmoved-2;
2051 if (mt->fromFile == gs->wkrmoved)
2052 gs->wkrmoved = -gs->wkrmoved-2;
2054 if ((piecetype(movedPiece) == ROOK) && (mt->fromRank == gs->ranks-1) && (gs->onMove == BLACK)) {
2055 if (mt->fromFile == gs->bqrmoved)
2056 gs->bqrmoved = -gs->bqrmoved-2;
2057 if (mt->fromFile == gs->bkrmoved)
2058 gs->bkrmoved = -gs->bkrmoved-2;
2060 if (piecetype(movedPiece) == KING) {
2061 if ((gs->onMove == WHITE) && (mt->fromFile == gs->wkmoved))
2062 gs->wkmoved = -gs->wkmoved-2;
2063 if ((gs->onMove == BLACK) && (mt->fromFile == gs->bkmoved))
2064 gs->bkmoved = -gs->bkmoved-2;
2067 if ((piecetype(movedPiece) == KING) &&
2068 ((mt->fromFile == gs->files/2) && (mt->toFile == gs->files-2)) &&
2069 mt->fromRank == mt->toRank) { /* Check for KS castling */
2070 gs->board[gs->files-3][mt->toRank] = gs->board[gs->files-1][mt->toRank];
2071 gs->board[gs->files-1][mt->toRank] = NOPIECE;
2073 if ((piecetype(movedPiece) == KING) &&
2074 ((mt->fromFile == gs->files/2) && (mt->toFile == 2)) &&
2075 mt->fromRank == mt->toRank) { /* Check for QS castling */
2076 gs->board[3][mt->toRank] = gs->board[0][mt->toRank];
2077 gs->board[0][mt->toRank] = NOPIECE;
2081 if (gs->onMove == BLACK)
2084 if (check_game_status) {
2085 /* Does this move result in check? */
2087 /* Check for checkmate */
2088 gs->onMove = CToggle(gs->onMove);
2089 if (!has_legal_move(gs))
2090 return MOVE_CHECKMATE;
2092 /* Check for stalemate */
2093 gs->onMove = CToggle(gs->onMove);
2094 if (!has_legal_move(gs))
2095 return gs->stalemate ? MOVE_STALEMATE : MOVE_CHECKMATE; // [HGM] in XQ and shatranj stalemate loses
2097 /* loon: check for insufficient mating material, first try */
2098 foobar = wCnt = bCnt = 0;
2099 for (i=0; i<gs->files; i++) {
2100 for (j=0; j<gs->ranks; j++) {
2101 int p = gs->board[i][j];
2102 switch(piecetype(p)) {
2114 if(p != NOPIECE && iscolor(p, WHITE)) wCnt++;
2115 if(iscolor(p, BLACK)) bCnt++;
2118 if(gs->bareKingLoses) { // [HGM] with bare-King-loses rule only KK is insuff. material
2119 if(gs->onMove == BLACK && wCnt == 1 && bCnt > 1) return MOVE_BARE;
2120 if(gs->onMove == WHITE && bCnt == 1 && wCnt > 1) return MOVE_BARE;
2121 if(bCnt == 1 && wCnt == 1) return MOVE_NOMATERIAL;
2122 } else if (foobar < 2)
2123 return MOVE_NOMATERIAL;
2125 gs->onMove = CToggle(gs->onMove);
2131 int backup_move(int g, int mode)
2133 struct game_state_t *gs;
2134 struct move_t *m, *m1;
2137 if (game_globals.garray[g].link >= 0) /*IanO: not implemented for bughouse yet */
2138 return MOVE_ILLEGAL;
2139 if (game_globals.garray[g].numHalfMoves < 1)
2140 return MOVE_ILLEGAL;
2141 gs = &game_globals.garray[g].game_state;
2142 m = (mode==REL_GAME) ? &game_globals.garray[g].moveList[game_globals.garray[g].numHalfMoves - 1] :
2143 &game_globals.garray[g].examMoveList[game_globals.garray[g].numHalfMoves - 1];
2144 if (m->toFile < 0) {
2145 return MOVE_ILLEGAL;
2147 if(m->fromFile == ALG_CASTLE) {
2148 // [HGM] castling in new format. Derive K and R moves
2149 int rank, kingFromFile;
2150 if(m->color == WHITE) {
2152 kingFromFile = -gs->wkmoved-2;
2153 if(kingFromFile<0) kingFromFile = -kingFromFile-2; // safety catch; should never happen?
2154 gs->wkmoved = kingFromFile;
2155 if(m->toRank > m->toFile) gs->wqrmoved = m->fromRank;
2156 else gs->wkrmoved = m->fromRank;
2159 kingFromFile = -gs->bkmoved-2;
2160 if(kingFromFile<0) kingFromFile = -kingFromFile-2; // safety catch; should never happen?
2161 gs->bkmoved = kingFromFile;
2162 if(m->toRank > m->toFile) gs->bqrmoved = m->fromRank;
2163 else gs->bkrmoved = m->fromRank;
2165 // remove first, as one might come back to a square the other left
2166 gs->board[m->toFile ][rank] = NOPIECE; // King toSqr
2167 gs->board[m->toRank ][rank] = NOPIECE; // Rook toSqr
2168 if(gs->board[m->fromRank][rank] != NOPIECE)
2169 gs->holding[gs->onMove==WHITE ? 1 : 0][piecetype(gs->board[m->fromRank][rank])-1]++; // put back in holdings (onMove not flipped yet!)
2170 if(gs->board[kingFromFile][rank] != NOPIECE)
2171 gs->holding[gs->onMove==WHITE ? 1 : 0][piecetype(gs->board[kingFromFile][rank])-1]++; // put back in holdings (onMove not flipped yet!)
2172 gs->board[m->fromRank][rank] = ROOK | m->color; // Rook fromSqr
2173 gs->board[kingFromFile][rank] = KING | m->color; // King fromSquare
2176 if(gs->board[m->fromFile][m->fromRank] != NOPIECE) { // [HGM] from-square occupied; move must have been Seirawan-style gating
2177 gs->holding[gs->onMove==WHITE ? 1 : 0][piecetype(gs->board[m->fromFile][m->fromRank])-1]++; // put back in holdings (onMove not flipped yet!)
2179 gs->board[m->fromFile][m->fromRank] = gs->board[m->toFile][m->toRank];
2180 if (m->piecePromotionTo != NOPIECE) {
2181 gs->board[m->fromFile][m->fromRank] = PAWN |
2182 colorval(gs->board[m->fromFile][m->fromRank]);
2185 When takeback a _first_ move of rook, the ??rmoved variable
2186 must be cleared . To check, if the move is first, we should
2188 *******************/
2189 if (piecetype(gs->board[m->fromFile][m->fromRank]) == ROOK) {
2190 if (m->color == WHITE) {
2191 if ((m->fromFile == -gs->wqrmoved-2) && (m->fromRank == 0)) {
2192 for (i = 2; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2193 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2194 if ((m1->fromFile == -gs->wqrmoved-2) && (m1->fromRank == 0))
2197 if (i == game_globals.garray[g].numHalfMoves - 1)
2198 gs->wqrmoved = m->fromFile;
2200 if ((m->fromFile == -gs->wkrmoved-2) && (m->fromRank == 0)) {
2201 for (i = 2; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2202 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2203 if ((m1->fromFile == -gs->wkrmoved-2) && (m1->fromRank == 0))
2206 if (i == game_globals.garray[g].numHalfMoves - 1)
2207 gs->wkrmoved = m->fromFile;
2210 if ((m->fromFile == -gs->bqrmoved-2) && (m->fromRank == gs->ranks-1)) {
2211 for (i = 3; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2212 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2213 if ((m1->fromFile == -gs->bkrmoved-2) && (m1->fromRank == gs->ranks-1))
2216 if (i == game_globals.garray[g].numHalfMoves - 1)
2217 gs->bqrmoved = m->fromFile;
2219 if ((m->fromFile == -gs->bkrmoved-2) && (m->fromRank == gs->ranks-1)) {
2220 for (i = 3; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2221 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2222 if ((m1->fromFile == -gs->wkrmoved-2) && (m1->fromRank == gs->ranks-1))
2225 if (i == game_globals.garray[g].numHalfMoves - 1)
2226 gs->bkrmoved = m->fromFile;
2230 if (piecetype(gs->board[m->fromFile][m->fromRank]) == KING) {
2231 gs->board[m->toFile][m->toRank] = m->pieceCaptured;
2233 /* [HGM] castlings are already intercepted due to new format; this code wrecks knightmate! */
2234 if (m->toFile - m->fromFile == 2) {
2235 gs->board[7][m->fromRank] = ROOK |
2236 colorval(gs->board[m->fromFile][m->fromRank]);
2237 gs->board[5][m->fromRank] = NOPIECE;
2240 If takeback a castling, the appropriates ??moved variables
2243 if (m->color == WHITE) {
2252 if (m->fromFile - m->toFile == 2) {
2253 gs->board[0][m->fromRank] = ROOK |
2254 colorval(gs->board[m->fromFile][m->fromRank]);
2255 gs->board[3][m->fromRank] = NOPIECE;
2258 If takeback a castling, the appropriate ??moved variables
2261 if (m->color == WHITE) {
2272 When takeback a _first_ move of king (not the castling),
2273 the ?kmoved variable must be cleared . To check, if the move is first,
2274 we should scan moveList.
2275 *******************/
2277 if (m->color == WHITE) {
2279 if ((m->fromFile == -gs->wkmoved-2) && (m->fromRank == 0)) {
2280 for (i = 2; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2281 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2282 if ((m1->fromFile == gs->wkmoved-2) && (m1->fromRank == 0))
2285 if (i == game_globals.garray[g].numHalfMoves - 1)
2286 gs->wkmoved = m->fromFile;
2289 if ((m->fromFile == -gs->bkmoved-2) && (m->fromRank == gs->ranks-1)) {
2290 for (i = 3; i < game_globals.garray[g].numHalfMoves - 1; i += 2) {
2291 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[i] : &game_globals.garray[g].examMoveList[i];
2292 if ((m1->fromFile == -gs->bkmoved-2) && (m1->fromRank == gs->ranks-1))
2295 if (i == game_globals.garray[g].numHalfMoves - 1)
2296 gs->bkmoved = m->fromFile;
2300 if (m->enPassant) { /* Do enPassant */
2301 gs->board[m->toFile][m->fromRank] = PAWN |
2302 (colorval(gs->board[m->fromFile][m->fromRank]) == WHITE ? BLACK : WHITE);
2303 gs->board[m->toFile][m->toRank] = NOPIECE;
2304 /* Should set the enpassant array, but I don't care right now */
2307 gs->board[m->toFile][m->toRank] = m->pieceCaptured;
2309 if (game_globals.garray[g].status != GAME_EXAMINE) {
2310 game_update_time(g);
2312 game_globals.garray[g].numHalfMoves--;
2313 if (game_globals.garray[g].status != GAME_EXAMINE) {
2314 if (game_globals.garray[g].wInitTime) { /* Don't update times in untimed games */
2317 if (m->color == WHITE) {
2318 if (net_globals.con[player_globals.parray[game_globals.garray[g].white].socket]->timeseal) { /* white uses timeseal? */
2319 game_globals.garray[g].wRealTime += (m->tookTime * 100);
2320 game_globals.garray[g].wRealTime -= (game_globals.garray[g].wIncrement * 100);
2321 game_globals.garray[g].wTime = game_globals.garray[g].wRealTime / 100;
2322 if (net_globals.con[player_globals.parray[game_globals.garray[g].black].socket]->timeseal) { /* opp uses timeseal? */
2323 game_globals.garray[g].bTime = game_globals.garray[g].bRealTime / 100;
2324 } else { /* opp has no timeseal */
2325 game_globals.garray[g].bTime += (game_globals.garray[g].lastDecTime - game_globals.garray[g].lastMoveTime);
2327 } else { /* white has no timeseal */
2328 game_globals.garray[g].wTime += m->tookTime;
2329 game_globals.garray[g].wTime -= game_globals.garray[g].wIncrement;
2330 if (net_globals.con[player_globals.parray[game_globals.garray[g].black].socket]->timeseal) { /* opp uses timeseal? */
2331 game_globals.garray[g].bTime = game_globals.garray[g].bRealTime / 100;
2332 } else { /* opp has no timeseal */
2333 game_globals.garray[g].bTime += (game_globals.garray[g].lastDecTime - game_globals.garray[g].lastMoveTime);
2337 if (net_globals.con[player_globals.parray[game_globals.garray[g].black].socket]->timeseal) { /* black uses timeseal? */
2338 game_globals.garray[g].bRealTime += (m->tookTime * 100);
2339 game_globals.garray[g].bRealTime -= (game_globals.garray[g].wIncrement * 100);
2340 game_globals.garray[g].bTime = game_globals.garray[g].bRealTime / 100;
2341 if (net_globals.con[player_globals.parray[game_globals.garray[g].white].socket]->timeseal) { /* opp uses timeseal? */
2342 game_globals.garray[g].wTime = game_globals.garray[g].wRealTime / 100;
2343 } else { /* opp has no timeseal */
2344 game_globals.garray[g].wTime += (game_globals.garray[g].lastDecTime - game_globals.garray[g].lastMoveTime);
2346 } else { /* black has no timeseal */
2347 game_globals.garray[g].bTime += m->tookTime;
2348 if (!game_globals.garray[g].bIncrement)
2349 game_globals.garray[g].bTime -= game_globals.garray[g].wIncrement;
2351 game_globals.garray[g].bTime -= game_globals.garray[g].bIncrement;
2352 if (net_globals.con[player_globals.parray[game_globals.garray[g].white].socket]->timeseal) { /* opp uses timeseal? */
2353 game_globals.garray[g].wTime = game_globals.garray[g].wRealTime / 100;
2354 } else { /* opp has no timeseal */
2355 game_globals.garray[g].wTime += (game_globals.garray[g].lastDecTime - game_globals.garray[g].lastMoveTime);
2360 if (game_globals.garray[g].numHalfMoves == 0)
2361 game_globals.garray[g].timeOfStart = now;
2362 game_globals.garray[g].lastMoveTime = now;
2363 game_globals.garray[g].lastDecTime = now;
2366 if (gs->onMove == BLACK)
2373 /******* Here begins the patch : ********************************
2374 Takeback of last move is done already, it's time to update enpassant
2375 array. (patch from Soso, added by Sparky 3/17/95)
2378 if (game_globals.garray[g].numHalfMoves > 0) {
2379 m1 = (mode==REL_GAME) ? &game_globals.garray[g].moveList[game_globals.garray[g].numHalfMoves - 1] :
2380 &game_globals.garray[g].examMoveList[game_globals.garray[g].numHalfMoves - 1];
2381 if (piecetype(gs->board[m1->toFile][m1->toRank]) == PAWN) {
2382 if ((m1->toRank - m1->fromRank) == 2) {
2383 if ((m1->toFile < gs->files-1) && gs->board[m1->toFile + 1][m1->toRank] == B_PAWN) {
2384 gs->ep_possible[1][m1->toFile + 1] = -1;
2386 if ((m1->toFile - 1 >= 0) && gs->board[m1->toFile - 1][m1->toRank] == B_PAWN) {
2387 gs->ep_possible[1][m1->toFile - 1] = 1;
2390 if ((m1->toRank - m1->fromRank) == -2) {
2391 if ((m1->toFile < gs->files-1) && gs->board[m1->toFile + 1][m1->toRank] == W_PAWN) {
2392 gs->ep_possible[0][m1->toFile + 1] = -1;
2394 if ((m1->toFile - 1 >= 0) && gs->board[m1->toFile - 1][m1->toRank] == W_PAWN) {
2395 gs->ep_possible[0][m1->toFile - 1] = 1;
2400 /************** and here's the end **************/