Files
brchess/src/move-do.c

363 lines
12 KiB
C

/* move-do.c - move do/undo.
*
* Copyright (C) 2021-2024 Bruno Raoult ("br")
* Licensed under the GNU General Public License v3.0 or later.
* Some rights reserved. See COPYING.
*
* You should have received a copy of the GNU General Public License along with this
* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
*
* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
*
*/
#include <malloc.h>
#include <ctype.h>
#include <stdlib.h>
#include "brlib.h"
#include "likely.h"
#include "bug.h"
#include "chessdefs.h"
#include "move.h"
#include "position.h"
#include "move-do.h"
#include "hash.h"
/**
* move_do() - do move.
* @pos: &pos_t position
* @move: move to apply
* @state: &state_t address where irreversible changes will be saved
*
* @move is applied to @pos:
* - bitboards and board are updated
* - counters are updated:
* - move count
* - 50-moves rule count
* - flags are possibly updated:
* - castling
* - en-passant
* - captured piece (excl. en-passant)
* - tt hash values are updated for:
* - side-to-move
* - en-passant
* - castling rights.
*
* @return: updated pos.
*/
pos_t *move_do(pos_t *pos, const move_t move) //, state_t *state)
{
//# ifdef DEBUG_MOVE_DO
// move_print(move, M_PR_NL | M_PR_LONG);
//# endif
//*state = pos->state; /* save irreversible changes */
color_t us = pos->turn, them = OPPONENT(us);
square_t from = move_from(move), to = move_to(move);
piece_t piece = pos->board[from];
piece_t captured = pos->board[to];
piece_type_t ptype = PIECE(piece);
piece_t new_piece = piece;
int up = sq_up(us);
hkey_t key = pos->key;
/* update key: switch turn, reset castling and ep */
key ^= zobrist_turn;
key ^= zobrist_castling[pos->castle];
key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
++pos->clock_50;
++pos->plycount;
pos->en_passant = SQUARE_NONE;
pos->turn = them;
pos->captured = captured;
bug_on(COLOR(piece) != us);
if (is_promotion(move)) {
bug_on(sq_rank(to) != sq_rel_rank(RANK_8, us));
new_piece = MAKE_PIECE(move_promoted(move), us);
}
if (captured != EMPTY) {
pos->clock_50 = 0;
//pos->captured = pos->board[to]; /* save capture info */
bug_on(pos->board[to] == EMPTY || COLOR(pos->captured) != them);
key ^= zobrist_pieces[captured][to];
pos_clr_sq(pos, to); /* clear square */
} else if (is_castle(move)) { /* handle rook move */
square_t rookfrom, rookto;
if (is_castle_K(move)) {
rookfrom = sq_rel(H1, us);
rookto = sq_rel(F1, us);
} else {
rookfrom = sq_rel(A1, us);
rookto = sq_rel(D1, us);
}
key ^= zobrist_pieces[pos->board[rookfrom]][rookto] ^
zobrist_pieces[pos->board[rookfrom]][rookfrom];
pos_set_sq(pos, rookto, pos->board[rookfrom]);
pos_clr_sq(pos, rookfrom);
//pos->castle = clr_castle(pos->castle, us);
} else if (ptype == PAWN) { /* pawn non capture or e.p. */
pos->clock_50 = 0;
if (is_dpush(move)) { /* if pawn double push, set e.p. */
pos->en_passant = from + up;
/* update ep key */
key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
} else if (is_enpassant(move)) { /* clear grabbed pawn */
square_t grabbed = to - up;
key ^= zobrist_pieces[pos->board[grabbed]][grabbed];
pos_clr_sq(pos, grabbed);
}
}
key ^= zobrist_pieces[piece][from] ^ zobrist_pieces[new_piece][to];
pos_clr_sq(pos, from); /* clear "from" and set "to" */
pos_set_sq(pos, to, new_piece);
if (ptype == KING)
pos->king[us] = to;
/* update castling flags
* As we always consider flags are valid, we :
* - adjust our flags if relative from is "E1", "A1", H1"
* - adjust opp flags if relative to if "A8", H8"
*/
if (can_castle(pos->castle, us)) { /* do we save time with this test ? */
square_t rel_e1 = sq_rel(E1, us);
square_t rel_a1 = sq_rel(A1, us);
square_t rel_h1 = sq_rel(H1, us);
if (from == rel_e1)
pos->castle = clr_castle(pos->castle, us);
else if (from == rel_a1)
pos->castle = clr_ooo(pos->castle, us);
else if (from == rel_h1)
pos->castle = clr_oo(pos->castle, us);
}
if (can_castle(pos->castle, them)) {
square_t rel_a8 = sq_rel(A8, us);
square_t rel_h8 = sq_rel(H8, us);
if (to == rel_a8)
pos->castle = clr_ooo(pos->castle, them);
else if (to == rel_h8)
pos->castle = clr_oo(pos->castle, them);
}
/* update castling rights key */
key ^= zobrist_castling[pos->castle];
pos->key = key;
bug_on(zobrist_verify(pos) == false);
return pos;
}
pos_t *move_do2(pos_t *pos, const move_t move, state_t *state)
{
//# ifdef DEBUG_MOVE_DO
// move_print(move, M_PR_NL | M_PR_LONG);
//# endif
color_t us = pos->turn, them = OPPONENT(us);
square_t from = move_from(move), to = move_to(move);
piece_t piece = pos->board[from];
piece_t captured = pos->board[to];
piece_type_t ptype = PIECE(piece);
piece_t new_piece = piece;
int up = sq_up(us);
hkey_t key = pos->key;
*state = pos->state; /* save irreversible changes */
/* update key: switch turn, reset castling and ep */
key ^= zobrist_turn;
key ^= zobrist_castling[pos->castle];
key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
++pos->clock_50;
++pos->plycount;
pos->en_passant = SQUARE_NONE;
pos->turn = them;
pos->captured = captured;
bug_on(COLOR(piece) != us);
if (is_promotion(move)) {
bug_on(sq_rank(to) != sq_rel_rank(RANK_8, us));
new_piece = MAKE_PIECE(move_promoted(move), us);
}
if (captured != EMPTY) {
pos->clock_50 = 0;
//pos->captured = pos->board[to]; /* save capture info */
bug_on(pos->board[to] == EMPTY || COLOR(pos->captured) != them);
key ^= zobrist_pieces[captured][to];
pos_clr_sq(pos, to); /* clear square */
} else if (is_castle(move)) { /* handle rook move */
square_t rookfrom, rookto;
if (is_castle_K(move)) {
rookfrom = sq_rel(H1, us);
rookto = sq_rel(F1, us);
} else {
rookfrom = sq_rel(A1, us);
rookto = sq_rel(D1, us);
}
key ^= zobrist_pieces[pos->board[rookfrom]][rookto];
key ^= zobrist_pieces[pos->board[rookfrom]][rookfrom];
pos_set_sq(pos, rookto, pos->board[rookfrom]);
pos_clr_sq(pos, rookfrom);
pos->castle = clr_castle(pos->castle, us);
} else if (ptype == PAWN) { /* pawn non capture or e.p. */
pos->clock_50 = 0;
if (is_dpush(move)) { /* if pawn double push, set e.p. */
pos->en_passant = from + up;
/* update key */
key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
} else if (is_enpassant(move)) { /* clear grabbed pawn */
square_t grabbed = to - up;
key ^= zobrist_pieces[pos->board[grabbed]][grabbed];
pos_clr_sq(pos, grabbed);
}
}
key ^= zobrist_pieces[piece][from];
key ^= zobrist_pieces[new_piece][to];
pos_clr_sq(pos, from); /* clear "from" and set "to" */
pos_set_sq(pos, to, new_piece);
if (ptype == KING)
pos->king[us] = to;
/* update castling flags
* As we always consider flags are valid, we :
* - adjust our flags if relative from is "E1", "A1", H1"
* - adjust opp flags if relative to if "A8", H8"
*/
if (can_castle(pos->castle, us)) { /* do we save time with this test ? */
square_t rel_e1 = sq_rel(E1, us);
square_t rel_a1 = sq_rel(A1, us);
square_t rel_h1 = sq_rel(H1, us);
if (from == rel_e1)
pos->castle = clr_castle(pos->castle, us);
else if (from == rel_a1)
pos->castle = clr_ooo(pos->castle, us);
else if (from == rel_h1)
pos->castle = clr_oo(pos->castle, us);
}
if (can_castle(pos->castle, them)) {
square_t rel_a8 = sq_rel(A8, us);
square_t rel_h8 = sq_rel(H8, us);
if (to == rel_a8)
pos->castle = clr_ooo(pos->castle, them);
else if (to == rel_h8)
pos->castle = clr_oo(pos->castle, them);
}
/* update castle key */
key ^= zobrist_castling[pos->castle];
pos->key = key;
bug_on(zobrist_verify(pos) == false);
return pos;
}
/**
* move_undo() - undo move.
* @pos: &pos_t position
* @move: move to undo
* @state: &state_t address where irreversible changes were saved
*
* @move is applied to @pos:
* - bitboards and board are updated
* - previous information is restored:
* - castling
* - en-passant
* - captured piece (excl. en-passant)
* - move count
* - 50-moves rule count
*
* @return: pos.
*/
pos_t *move_undo(pos_t *pos, const move_t move)
{
color_t them = pos->turn, us = OPPONENT(them);
square_t from = move_from(move), to = move_to(move);
piece_t piece = pos->board[to];
int up = sq_up(them);
if (is_promotion(move))
piece = MAKE_PIECE(PAWN, us);
pos_clr_sq(pos, to); /* always clear "to" ... */
pos_set_sq(pos, from, piece); /* ... and set "from" */
if (PIECE(piece) == KING)
pos->king[us] = from;
if (pos->captured != EMPTY) {
pos_set_sq(pos, to, pos->captured); /* restore captured piece */
} else if (is_castle(move)) { /* make reverse rook move */
square_t rookfrom, rookto;
if (is_castle_K(move)) {
rookfrom = sq_rel(F1, us);
rookto = sq_rel(H1, us);
} else {
rookfrom = sq_rel(D1, us);
rookto = sq_rel(A1, us);
}
pos_set_sq(pos, rookto, pos->board[rookfrom]);
pos_clr_sq(pos, rookfrom);
} else if (is_enpassant(move)) { /* restore grabbed pawn */
square_t grabbed = to + up;
pos_set_sq(pos, grabbed, MAKE_PIECE(PAWN, them));
}
//pos->state = *state; /* restore irreversible changes */
pos->turn = us;
return pos;
}
pos_t *move_undo2(pos_t *pos, const move_t move, const state_t *state)
{
color_t them = pos->turn, us = OPPONENT(them);
square_t from = move_from(move), to = move_to(move);
piece_t piece = pos->board[to];
int up = sq_up(them);
if (is_promotion(move))
piece = MAKE_PIECE(PAWN, us);
pos_clr_sq(pos, to); /* always clear "to" ... */
pos_set_sq(pos, from, piece); /* ... and set "from" */
if (PIECE(piece) == KING)
pos->king[us] = from;
if (pos->captured != EMPTY) {
pos_set_sq(pos, to, pos->captured); /* restore captured piece */
} else if (is_castle(move)) { /* make reverse rook move */
square_t rookfrom, rookto;
if (is_castle_K(move)) {
rookfrom = sq_rel(F1, us);
rookto = sq_rel(H1, us);
} else {
rookfrom = sq_rel(D1, us);
rookto = sq_rel(A1, us);
}
pos_set_sq(pos, rookto, pos->board[rookfrom]);
pos_clr_sq(pos, rookfrom);
} else if (is_enpassant(move)) { /* restore grabbed pawn */
square_t grabbed = to + up;
pos_set_sq(pos, grabbed, MAKE_PIECE(PAWN, them));
}
pos->state = *state; /* restore irreversible changes */
pos->turn = us;
return pos;
}