/* ---------------------------------------------------------------------------------------
void generate_moves(CHESS_STATE *current_state)
purpose: the search tree function - gets all child states for a given state.
NOTE: this function simply gets all moves for an immediate chess state using
bitboard maths etc. It _may_ include illegal moves (eg if king is left exposed.
Such illegal moves are filtered out using iterative deepening function (see later
in source), using flg_is_illegal flag on node.
--------------------------------------------------------------------------------------- */
void generate_moves(CHESS_STATE *current_state)
{
bitboard pieces=0; // bitboard of pieces under investigation
bitboard piece; // bitboard of single piece
COLOR_ENUM color = (current_state->flg_is_white_move) ? BB_WHITE : BB_BLACK;
COLOR_ENUM opponent_color = (current_state->flg_is_white_move) ? BB_BLACK : BB_WHITE;
// calculated bitboards
int i;
// empty and opponents squares cached for performance
bitboard empty_squares = EMPTY_BOARD;
bitboard opponents_squares = EMPTY_BOARD;
for (i=0; i< BB_COUNT; i++)
{
empty_squares |= current_state->boards[i];
}
empty_squares = ~empty_squares;
for (i=0; i<6; i++)
{
opponents_squares |= current_state->boards[opponent_color+i];
}
// pawns
pawn_moves(current_state,empty_squares);
pawn_double_moves(current_state,empty_squares);
en_passant_moves(current_state);
pawn_capture_moves(current_state,empty_squares, opponents_squares);
//knight
fp_cached_move_mask knight_func = &cached_knight_move_mask;
simple_move_mask_moves(current_state, BB_KNIGHT, knight_func, empty_squares, opponents_squares);
//king
fp_cached_move_mask king_func = &cached_king_move_mask;
simple_move_mask_moves(current_state, BB_KING, king_func, empty_squares, opponents_squares);
// rook
fp_cached_sliding_move_mask rook_func = &cached_rook_move_mask;
sliding_moves(current_state,empty_squares,opponents_squares,BB_ROOK,rook_func);
// bishop
fp_cached_sliding_move_mask bishop_func = &cached_bishop_move_mask;
sliding_moves(current_state,empty_squares,opponents_squares,BB_BISHOP,bishop_func);
// queen
sliding_moves(current_state,empty_squares,opponents_squares,BB_QUEEN,rook_func);
sliding_moves(current_state,empty_squares,opponents_squares,BB_QUEEN,bishop_func);
}
void gen_moves(const board& b, piece_colour pc, move* movelist, int& num_moves)
{
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
row_col rc(i, j);
square s = b.get(rc);
if (pc == get_piece_colour(s))
{
piece_type pt = get_piece_type(s);
switch (pt)
{
case NONE:
assert(0); // only here if square contains one of our pieces
break;
case PAWN:
pawn_moves(pc, rc, b, movelist, num_moves);
break;
case KNIGHT:
knight_moves(pc, rc, b, movelist, num_moves);
break;
case BISHOP:
bishop_moves(pc, rc, b, movelist, num_moves);
break;
case ROOK:
rook_moves(pc, rc, b, movelist, num_moves);
break;
case KING:
king_moves(pc, rc, b, movelist, num_moves);
break;
case QUEEN:
queen_moves(pc, rc, b, movelist, num_moves);
break;
}
}
}
}
}
/*
* return the non-eat (simple) moves.
* curr = starting coordinate of the move
* max_step = length of maximal possible step (1 for man, BOARD_SIZE for king)
* in case of an error - return error_moves
*/
moves get_simple_moves(settings * set, cord curr){
char piece = board_piece(set->board, curr);
int color = which_color(piece);
int type = tolower(piece);
moves all_simple_moves = { 0 };
switch (type)
{
case PAWN:
return pawn_moves(set, curr, color);
case BISHOP:
return bishop_moves(set, curr, color, FALSE);
case ROOK:
return rook_moves(set, curr, color, FALSE);
case KNIGHT:
return knight_moves(set, curr, color);
case QUEEN:
return queen_moves(set, curr, color, FALSE);
case KING:
return king_moves(set, curr, color);
default:
return all_simple_moves;
}
}
/* return the set of all squares the given piece is able to move to, without
* considering a king left in check */
uint64_t generate_moves(Game *game, int tile) {
Board *board = &(game->board);
int colour = !(board->b[WHITE][OCCUPIED] & (1ull << tile));
int type = board->mailbox[tile];
uint64_t moves = 0;
uint64_t blockers;
switch(type) {
case PAWN:
moves = pawn_moves(board, tile);
int x = tile % 8, y = tile / 8;
if((game->ep == x + 1 || game->ep == x - 1) && (y == 4 - colour))
moves |= 1ull << ((5 - colour * 3) * 8 + game->ep);
break;
case KNIGHT:
moves = knight_moves[tile];
break;
case BISHOP:
moves = bishop_moves(board, tile);
break;
case ROOK:
moves = rook_moves(board, tile);
break;
case QUEEN:
moves = bishop_moves(board, tile) | rook_moves(board, tile);
break;
case KING:
moves = king_moves[tile];
/* queenside castling */
if(game->can_castle[colour][QUEENSIDE]) {
blockers = ((1ull << (tile - 1)) | (1ull << (tile - 2))
| (1ull << (tile - 3))) & board->occupied;
/* if there are no pieces in the way and no intermediate tiles are
* threatened, add the move
*/
if(!blockers && !is_threatened(board, tile)
&& !is_threatened(board, tile - 1)
&& !is_threatened(board, tile - 2))
moves |= 1ull << (tile - 2);
}
/* kingisde castling */
if(game->can_castle[colour][KINGSIDE]) {
blockers = ((1ull << (tile + 1)) | (1ull << (tile + 2)))
& board->occupied;
/* if there are no pieces in the way and no intermediate tiles are
* threatened, add the move
*/
if(!blockers && !is_threatened(board, tile)
&& !is_threatened(board, tile + 1)
&& !is_threatened(board, tile + 2))
moves |= 1ull << (tile + 2);
}
break;
}
/* return the moves, removing the final tile if it ended on our own
* colour.
*/
return moves & ~board->b[colour][OCCUPIED];
}