U64 hash_key(const board_t *board) {
ASSERT(board != nullptr);
// init
U64 key = 0;
// pieces
for (S8 colour = 0; colour < ColourNb; ++colour) {
for (auto sq = board->piece[colour].begin(); sq != board->piece[colour].end(); ++sq) {
const S32 piece = board->square[*sq];
key ^= hash_piece_key(piece, *sq);
}
for (auto sq = board->pawn[colour].begin(); sq != board->pawn[colour].end(); ++sq) {
const S32 piece = board->square[*sq];
key ^= hash_piece_key(piece, *sq);
}
}
// castle flags
key ^= hash_castle_key(board->flags);
// en-passant square
const S32 sq = board->ep_square;
if (sq != SquareNone) key ^= hash_ep_key(sq);
// turn
key ^= hash_turn_key(board->turn);
return key;
}
uint64 hash_key(const board_t * board) {
uint64 key;
int colour;
const sq_t * ptr;
int sq, piece;
ASSERT(board!=NULL);
// init
key = 0;
// pieces
for (colour = 0; colour < ColourNb; colour++) {
for (ptr = &board->piece[colour][0]; (sq=*ptr) != SquareNone; ptr++) {
piece = board->square[sq];
key ^= hash_piece_key(piece,sq);
}
for (ptr = &board->pawn[colour][0]; (sq=*ptr) != SquareNone; ptr++) {
piece = board->square[sq];
key ^= hash_piece_key(piece,sq);
}
}
// castle flags
key ^= hash_castle_key(board->flags);
// en-passant square
sq = board->ep_square;
if (sq != SquareNone) key ^= hash_ep_key(sq);
// turn
key ^= hash_turn_key(board->turn);
return key;
}
void hash_init() {
for (U8 i = 0; i < 16; ++i)
Castle64[i] = hash_castle_key(i);
}
void move_do(board_t * board, int move) {
int me, opp;
int from, to;
int piece, pos, capture;
int old_flags, new_flags;
int sq, ep_square;
int pawn;
ASSERT(board_is_ok(board));
ASSERT(move_is_ok(move));
ASSERT(move_is_pseudo(move,board));
// init
me = board->turn;
opp = colour_opp(me);
from = move_from(move);
to = move_to(move);
piece = board->square[from];
ASSERT(colour_equal(piece,me));
pos = board->pos[from];
ASSERT(pos>=0);
// update turn
board->turn = opp;
board->key ^= random_64(RandomTurn);
// update castling rights
old_flags = board_flags(board);
if (piece_is_king(piece)) {
board->castle[me][SideH] = SquareNone;
board->castle[me][SideA] = SquareNone;
}
if (board->castle[me][SideH] == from) board->castle[me][SideH] = SquareNone;
if (board->castle[me][SideA] == from) board->castle[me][SideA] = SquareNone;
if (board->castle[opp][SideH] == to) board->castle[opp][SideH] = SquareNone;
if (board->castle[opp][SideA] == to) board->castle[opp][SideA] = SquareNone;
new_flags = board_flags(board);
board->key ^= hash_castle_key(new_flags^old_flags); // HACK
// update en-passant square
ep_square = sq = board->ep_square;
if (sq != SquareNone) {
board->key ^= random_64(RandomEnPassant+square_file(sq));
board->ep_square = SquareNone;
}
if (piece_is_pawn(piece) && abs(to-from) == 32) {
pawn = piece_make_pawn(opp);
if (board->square[to-1] == pawn || board->square[to+1] == pawn) {
board->ep_square = sq = (from + to) / 2;
board->key ^= random_64(RandomEnPassant+square_file(sq));
}
}
// update ply number (captures are handled later)
board->ply_nb++;
if (piece_is_pawn(piece)) board->ply_nb = 0; // conversion
// update move number
if (me == Black) board->move_nb++;
// castle
if (colour_equal(board->square[to],me)) {
int rank;
int king_from, king_to;
int rook_from, rook_to;
int rook;
rank = colour_is_white(me) ? Rank1 : Rank8;
king_from = from;
rook_from = to;
if (to > from) { // h side
king_to = square_make(FileG,rank);
rook_to = square_make(FileF,rank);
} else { // a side
king_to = square_make(FileC,rank);
rook_to = square_make(FileD,rank);
}
// remove the rook
pos = board->pos[rook_from];
ASSERT(pos>=0);
rook = Rook64 | me; // HACK
square_clear(board,rook_from,rook);
// move the king
square_move(board,king_from,king_to,piece);
// put the rook back
square_set(board,rook_to,rook,pos);
ASSERT(board->key==hash_key(board));
return;
}
// remove the captured piece
if (piece_is_pawn(piece) && to == ep_square) {
// en-passant capture
sq = square_ep_dual(to);
capture = board->square[sq];
ASSERT(capture==piece_make_pawn(opp));
square_clear(board,sq,capture);
board->ply_nb = 0; // conversion
} else {
capture = board->square[to];
if (capture != Empty) {
// normal capture
ASSERT(colour_equal(capture,opp));
ASSERT(!piece_is_king(capture));
square_clear(board,to,capture);
board->ply_nb = 0; // conversion
}
}
// move the piece
if (move_is_promote(move)) {
// promote
square_clear(board,from,piece);
piece = move_promote_hack(move) | me; // HACK
square_set(board,to,piece,pos);
} else {
// normal move
square_move(board,from,to,piece);
}
ASSERT(board->key==hash_key(board));
}
void hash_init() {
int i;
for (i = 0; i < 16; i++) Castle64[i] = hash_castle_key(i);
}
