/*
* Add all pseudo-legal non-capturing moves that the given piece (N/B/Q/K)
* can make, with the exception of castles.
*/
static void generate_piece_noncaptures(const position_t* pos,
square_t from,
piece_t piece,
move_t** moves_head)
{
move_t* moves = *moves_head;
square_t to;
if (piece_slide_type(piece) == NONE) {
// not a sliding piece, just iterate over dest. squares
for (const direction_t* delta = piece_deltas[piece]; *delta; ++delta) {
to = from + *delta;
if (pos->board[to] != EMPTY) continue;
moves = add_move(pos,
create_move(from, to, piece, NONE),
moves);
}
} else {
// a sliding piece, keep going until we hit something
for (const direction_t* delta = piece_deltas[piece]; *delta; ++delta) {
to = from + *delta;
while (pos->board[to] == EMPTY) {
moves = add_move(pos,
create_move(from, to, piece, NONE),
moves);
to += *delta;
}
}
}
*moves_head = moves;
}
/*
* Add all pseudo-legal captures that the given pawn can make.
*/
static void generate_pawn_captures(const position_t* pos,
square_t from,
piece_t piece,
move_t** moves_head)
{
color_t side = pos->side_to_move;
int cap_left = side == WHITE ? 15 : -15;
int cap_right = side == WHITE ? 17 : -17;
square_t to;
rank_t r_rank = relative_rank[side][square_rank(from)];
move_t* moves = *moves_head;
if (r_rank < RANK_7) {
// non-promote captures
to = from + cap_left;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
} else if (to == pos->ep_square && pos->board[to] == EMPTY) {
moves = add_move(pos, create_move_enpassant(from, to, piece,
pos->board[to + pawn_push[side^1]]), moves);
}
to = from + cap_right;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
} else if (to == pos->ep_square && pos->board[to] == EMPTY) {
moves = add_move(pos, create_move_enpassant(from, to, piece,
pos->board[to + pawn_push[side^1]]), moves);
}
} else {
// capture/promotes
to = from + cap_left;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
for (piece_t promoted=QUEEN; promoted > PAWN; --promoted) {
moves = add_move(pos, create_move_promote(from, to, piece,
pos->board[to], promoted), moves);
}
}
to = from + cap_right;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
for (piece_t promoted=QUEEN; promoted > PAWN; --promoted) {
moves = add_move(pos, create_move_promote(from, to, piece,
pos->board[to], promoted), moves);
}
}
}
*moves_head = moves;
}
int get_valid_move_count(int x, int y, enum cell_contents board[][BOARD_WIDTH])
{
int count = 0;
struct move move;
/* check all four directions */
move = create_move(x, y, x - 2, y);
if (is_valid_move(move, board, NULL)) count++;
move = create_move(x, y, x + 2, y);
if (is_valid_move(move, board, NULL)) count++;
move = create_move(x, y, x, y - 2);
if (is_valid_move(move, board, NULL)) count++;
move = create_move(x, y, x, y + 2);
if (is_valid_move(move, board, NULL)) count++;
return count;
}
/*
* Generate all non-capturing, non-promoting pawn moves.
*/
static void generate_pawn_quiet_moves(const position_t* pos,
square_t from,
piece_t piece,
move_t** moves_head)
{
color_t side = pos->side_to_move;
square_t to;
rank_t r_rank = relative_rank[side][square_rank(from)];
move_t* moves = *moves_head;
to = from + pawn_push[side];
if (r_rank == RANK_7 || pos->board[to] != EMPTY) return;
moves = add_move(pos, create_move(from, to, piece, EMPTY), moves);
to += pawn_push[side];
if (r_rank == RANK_2 && pos->board[to] == EMPTY) {
// initial two-square push
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
}
*moves_head = moves;
}
Move str_to_move(char *string)
{
for(int i = 0; i < 4; i += 1)
if(string[i] == '\0') return 0;
if(!((string[0] >= 'a' && string[0] <= 'h') &&
(string[1] >= '1' && string[1] <= '8') &&
(string[2] >= 'a' && string[2] <= 'h') &&
(string[3] >= '1' && string[3] <= '8'))) return 0;
int from = ('8' - string[1] + 2) * 10 + (string[0] - 'a' + 1);
int to = ('8' - string[3] + 2) * 10 + (string[2] - 'a' + 1);
int broken = board[to];
int turn = 0;
switch(string[4])
{
case 'q': turn = create_figure(turn_to_move, QUEEN); break;
case 'r': turn = create_figure(turn_to_move, ROOK); break;
case 'b': turn = create_figure(turn_to_move, BISHOP); break;
case 'n': turn = create_figure(turn_to_move, KNIGHT); break;
}
return create_move(from, to, broken, turn);
}
int
movegen(struct Game* game, int move_count)
{
U64 temp_move, temp_move2, temp_piece;
U32 from, to, move;
U64 free_squares = game->board[OCCUPIED][0];
if (game->to_move == WHITE)
{
/***************/
/* WHITE PAWNS */
/***************/
temp_move = step_up(game->board[PAWNS][WHITE]) & free_squares;
temp_move2 = temp_move;
/* single pushes */
while (temp_move)
{
to = bit_scan_forward(temp_move);
if (to/8 == 7)
{ /* time for a promotion */
game->move_buffer[move_count++] = create_move(to-8,to,BISHOP_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to-8,to,KNIGHT_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to-8,to,ROOK_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to-8,to,QUEEN_PROMO_FLAG);
} else game->move_buffer[move_count++] = create_move(to-8,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* double pushes */
temp_move2 = step_up(temp_move2) & free_squares & rank4;
while (temp_move2)
{
to = bit_scan_forward(temp_move2);
game->move_buffer[move_count++] = create_move(to-16,to,DOUBLE_PAWN_PUSH_FLAG);
temp_move2 &= temp_move2 - 1;
}
/* captures */
/* TODO: add en passante capture */
temp_piece = game->board[PAWNS][WHITE];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move = pawn_attacks[WHITE][from] & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
if (to/8 == 7)
{ /* time for a promotion */
game->move_buffer[move_count++] = create_move(from,to,BISHOP_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,KNIGHT_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,ROOK_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,QUEEN_PROMO_CAPTURE_FLAG);
} else game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/*****************/
/* WHITE KNIGHTS */
/*****************/
temp_piece = game->board[KNIGHTS][WHITE];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
/* quiets */
temp_move = knight_table[from] & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = knight_table[from] & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/*****************/
/* WHITE BISHOPS */
/*****************/
temp_piece = game->board[BISHOPS][WHITE];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_bishop_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/***************/
/* WHITE ROOKS */
/***************/
temp_piece = game->board[ROOKS][WHITE];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_rook_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/****************/
/* WHITE QUEENS */
/****************/
temp_piece = game->board[QUEENS][WHITE];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_queen_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/**************/
/* WHITE KINGS */
/**************/
temp_piece = game->board[KINGS][WHITE];
from = bit_scan_forward(temp_piece);
/* quiets */
temp_move = king_table[from] & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = king_table[from] & game->board[PIECES][BLACK];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
/* TODO: add castling moves here after writing is_attacked function */
} else { /* to_move == BLACK */
/***************/
/* BLACK PAWNS */
/***************/
temp_move = step_down(game->board[PAWNS][BLACK]) & free_squares;
temp_move2 = temp_move;
/* single pushes */
while (temp_move)
{
to = bit_scan_forward(temp_move);
if (to/8 == 0)
{ /* time for a promotion */
game->move_buffer[move_count++] = create_move(to+8,to,BISHOP_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to+8,to,KNIGHT_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to+8,to,ROOK_PROMO_FLAG);
game->move_buffer[move_count++] = create_move(to+8,to,QUEEN_PROMO_FLAG);
} else game->move_buffer[move_count++] = create_move(to+8,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* double pushes */
temp_move2 = step_down(temp_move2) & free_squares & rank5;
while (temp_move2)
{
to = bit_scan_forward(temp_move2);
game->move_buffer[move_count++] = create_move(to+16,to,DOUBLE_PAWN_PUSH_FLAG);
temp_move2 &= temp_move2 - 1;
}
/* captures */
/* TODO: add en passante capture */
temp_piece = game->board[PAWNS][BLACK];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move = pawn_attacks[BLACK][from] & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
if (to/8 == 7)
{ /* time for a promotion */
game->move_buffer[move_count++] = create_move(from,to,BISHOP_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,KNIGHT_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,ROOK_PROMO_CAPTURE_FLAG);
game->move_buffer[move_count++] = create_move(from,to,QUEEN_PROMO_CAPTURE_FLAG);
} else game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/*****************/
/* BLACK KNIGHTS */
/*****************/
temp_piece = game->board[KNIGHTS][BLACK];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
/* quiets */
temp_move = knight_table[from] & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = knight_table[from] & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/*****************/
/* BLACK BISHOPS */
/*****************/
temp_piece = game->board[BISHOPS][BLACK];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_bishop_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/***************/
/* BLACK ROOKS */
/***************/
temp_piece = game->board[ROOKS][BLACK];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_rook_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/****************/
/* BLACK QUEENS */
/****************/
temp_piece = game->board[QUEENS][BLACK];
while (temp_piece)
{
from = bit_scan_forward(temp_piece);
temp_move2 = get_queen_attacks(game->board[OCCUPIED][1], from);
/* quiets */
temp_move = temp_move2 & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = temp_move2 & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
temp_piece &= temp_piece - 1;
}
/**************/
/* BLACK KINGS */
/**************/
temp_piece = game->board[KINGS][BLACK];
from = bit_scan_forward(temp_piece);
/* quiets */
temp_move = king_table[from] & free_squares;
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,QUIET_FLAG);
temp_move &= temp_move - 1;
}
/* captures */
temp_move = king_table[from] & game->board[PIECES][WHITE];
while (temp_move)
{
to = bit_scan_forward(temp_move);
game->move_buffer[move_count++] = create_move(from,to,CAPTURE_FLAG);
temp_move &= temp_move - 1;
}
}
return move_count;
}
int generate_captures(Move *movelist)
{
int horizontal2 = turn_to_move == WHITE? 8 : 3;
int horizontal7 = turn_to_move == WHITE? 3 : 8;
int direction_of_pawns = turn_to_move == WHITE? -10: 10;
int captures_of_pawns[2] = {direction_of_pawns + 1, direction_of_pawns - 1};
int place_of_king = turn_to_move == WHITE? place_of_white_king:
place_of_black_king;
int n = 0;
for(int i = 0; i < 8; i += 1)
{
int tmp = place_of_king + moves_of_king[i];
if(get_color(board[tmp]) == not_turn_to_move)
{
movelist[n] = create_move(place_of_king, tmp, board[tmp], 0);
n += 1;
}
}
for(int i64 = 0; i64 < 64; i64 += 1)
{
int current_cell = board64[i64];
int figure = board[current_cell];
if(get_color(figure) != turn_to_move)
continue;
switch(get_value(figure))
{
case QUEEN:
for(int i = 0; i < 8; i += 1)
{
int inc = directions_of_queen[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
x += inc;
if(get_color(board[x]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case ROOK:
for(int i = 0; i < 4; i += 1)
{
int inc = directions_of_rook[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
x += inc;
if(get_color(board[x]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case BISHOP:
for(int i = 0; i < 4; i += 1)
{
int inc = directions_of_bishop[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
x += inc;
if(get_color(board[x]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case KNIGHT:
for(int i = 0; i < 8; i += 1)
{
int tmp = current_cell + moves_of_knight[i];
if(get_color(board[tmp]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, tmp, board[tmp], 0);
n += 1;
}
}
break;
case PAWN:
for(int i = 0; i < 2; i += 1)
{
int tmp = current_cell + captures_of_pawns[i];
if(get_color(board[tmp]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, tmp, board[tmp], 0);
n += 1;
}
}
}
}
for(int i = 0; i < n; i += 1)
{
Move i_move = movelist[i];
make_move(i_move);
if(in_check(not_turn_to_move))
{
movelist[i] = movelist[n - 1];
n -= 1;
i -= 1;
}
unmake_move(i_move);
}
return n;
}
int generate_moves(Move *movelist)
{
int horizontal2 = turn_to_move == WHITE? 8 : 3;
int horizontal7 = turn_to_move == WHITE? 3 : 8;
int direction_of_pawns = turn_to_move == WHITE? -10: 10;
int captures_of_pawns[2] = {direction_of_pawns + 1, direction_of_pawns - 1};
int place_of_king = turn_to_move == WHITE? place_of_white_king:
place_of_black_king;
int n = 0;
int king_castling, queen_castling;
if(turn_to_move == WHITE)
{
king_castling = ply->castlings & K_castling;
queen_castling = ply->castlings & Q_castling;
}
else
{
king_castling = ply->castlings & k_castling;
queen_castling = ply->castlings & q_castling;
}
int is_in_check = in_check(turn_to_move);
for(int i = 0; i < 8; i += 1)
{
int i_move = moves_of_king[i];
int tmp = place_of_king + i_move;
if(board[tmp] == EMPTY || get_color(board[tmp]) == not_turn_to_move)
{
int i_move_is_possible = 0;
Move tmp_move = create_move(place_of_king, tmp, board[tmp], 0);
make_move(tmp_move);
if(!in_check(not_turn_to_move))
{
i_move_is_possible = 1;
movelist[n] = tmp_move;
n += 1;
}
unmake_move(tmp_move);
if(is_in_check || !i_move_is_possible || board[tmp] != EMPTY)
continue;
if(i_move == 1 && king_castling && board[place_of_king + 2] == EMPTY)
{
movelist[n] = create_move(place_of_king, place_of_king + 2, 0, 0);
n += 1;
}
if(i_move == -1 && queen_castling &&
board[place_of_king - 2] == EMPTY &&
board[place_of_king - 3] == EMPTY)
{
movelist[n] = create_move(place_of_king, place_of_king - 2, 0, 0);
n += 1;
}
}
}
if(ply->en_passant)
{
for(int i = 0; i < 2; i += 1)
{
int tmp = ply->en_passant - captures_of_pawns[i];
if(board[tmp] == create_figure(turn_to_move, PAWN))
{
movelist[n] = create_move(tmp, ply->en_passant, 0, 0);
n += 1;
}
}
}
for(int i64 = 0; i64 < 64; i64 += 1)
{
int current_cell = board64[i64];
int figure = board[current_cell];
if(get_color(figure) != turn_to_move)
continue;
switch(get_value(figure))
{
case QUEEN:
for(int i = 0; i < 8; i += 1)
{
int inc = directions_of_queen[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
{
movelist[n] = create_move(current_cell, x, 0, 0);
n += 1;
x += inc;
}
if(get_color(board[x]) == not_turn_to_move )
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case ROOK:
for(int i = 0; i < 4; i += 1)
{
int inc = directions_of_rook[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
{
movelist[n] = create_move(current_cell, x, 0, 0);
n += 1;
x += inc;
}
if(get_color(board[x]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case BISHOP:
for(int i = 0; i < 4; i += 1)
{
int inc = directions_of_bishop[i];
int x = current_cell + inc;
while(board[x] == EMPTY)
{
movelist[n] = create_move(current_cell, x, 0, 0);
n += 1;
x += inc;
}
if(get_color(board[x]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, x, board[x], 0);
n += 1;
}
}
break;
case KNIGHT:
for(int i = 0; i < 8; i += 1)
{
int tmp = current_cell + moves_of_knight[i];
if(board[tmp] == EMPTY ||
get_color(board[tmp]) == not_turn_to_move)
{
movelist[n] = create_move(current_cell, tmp, board[tmp], 0);
n += 1;
}
}
break;
case PAWN:
;int tmp = current_cell + direction_of_pawns;
if(board[tmp] == EMPTY)
{
if(current_cell/10 == horizontal7)
{
for(int j = 0; j < 4; j += 1)
{
movelist[n] = create_move(current_cell, tmp, 0,
create_figure(turn_to_move, turn_figures[j]));
n += 1;
}
}
else
{
movelist[n] = create_move(current_cell, tmp, 0, 0);
n += 1;
}
tmp += direction_of_pawns;
if(board[tmp] == EMPTY && current_cell/10 == horizontal2)
{
movelist[n] = create_move(current_cell, tmp, 0, 0);
n += 1;
}
}
for(int i = 0; i < 2; i += 1)
{
int tmp = current_cell + captures_of_pawns[i];
if(get_color(board[tmp]) == not_turn_to_move)
{
if(current_cell/10 == horizontal7)
{
for(int j = 0; j < 4; j += 1)
{
movelist[n] = create_move(current_cell, tmp, board[tmp],
create_figure(turn_to_move, turn_figures[j]));
n += 1;
}
}
else
{
movelist[n] = create_move(current_cell, tmp, board[tmp], 0);
n += 1;
}
}
}
}
}
for(int i = 0; i < n; i += 1)
{
Move i_move = movelist[i];
make_move(i_move);
if(in_check(not_turn_to_move))
{
movelist[i] = movelist[n - 1];
n -= 1;
i -= 1;
}
unmake_move(i_move);
}
return n;
}
/*
* Add all pseudo-legal captures that the given piece (N/B/Q/K) can make.
*/
static void generate_piece_captures(const position_t* pos,
square_t from,
piece_t piece,
move_t** moves_head)
{
move_t* moves = *moves_head;
square_t to;
// Note: I unrolled all these loops to handle each direction explicitly.
// The idea was to increase performance, but it's only about 1% faster
// for much more code, so it's possible I'll change this back later.
switch (piece_type(piece)) {
case KING:
to = from - 17;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 16;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 15;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 1;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 1;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 15;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 16;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 17;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
break;
case KNIGHT:
to = from - 33;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 31;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 18;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from - 14;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 14;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 18;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 31;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
to = from + 33;
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
break;
case BISHOP:
for (to=from-17; pos->board[to]==EMPTY; to-=17) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from-15; pos->board[to]==EMPTY; to-=15) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+15; pos->board[to]==EMPTY; to+=15) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+17; pos->board[to]==EMPTY; to+=17) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
break;
case ROOK:
for (to=from-16; pos->board[to]==EMPTY; to-=16) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from-1; pos->board[to]==EMPTY; to-=1) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+1; pos->board[to]==EMPTY; to+=1) {}
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+16; pos->board[to]==EMPTY; to+=16) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
break;
case QUEEN:
for (to=from-17; pos->board[to]==EMPTY; to-=17) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from-16; pos->board[to]==EMPTY; to-=16) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from-15; pos->board[to]==EMPTY; to-=15) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from-1; pos->board[to]==EMPTY; to-=1) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+1; pos->board[to]==EMPTY; to+=1) {}
if (pos->board[to] != EMPTY && can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+15; pos->board[to]==EMPTY; to+=15) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+16; pos->board[to]==EMPTY; to+=16) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
for (to=from+17; pos->board[to]==EMPTY; to+=17) {}
if (can_capture(piece, pos->board[to])) {
moves = add_move(pos, create_move(from, to, piece,
pos->board[to]), moves);
}
break;
default: assert(false);
}
*moves_head = moves;
}
/*
* Generate all non-capturing, non-promoting, pseudo-legal checks. Used for
* quiescent move generation.
*/
int generate_pseudo_checks(const position_t* pos, move_t* moves)
{
move_t* moves_head = moves;
color_t side = pos->side_to_move, other_side = side^1;
square_t king_sq = pos->pieces[other_side][0];
for (int i = 0; i < pos->num_pawns[side]; ++i) {
square_t from = pos->pawns[side][i];
square_t to = INVALID_SQUARE;
piece_t piece = pos->board[from];
// Figure out whether or not we can discover check by moving.
direction_t discover_check_dir = 0;
bool will_discover_check;
const attack_data_t* king_atk = &get_attack_data(from, king_sq);
if ((king_atk->possible_attackers & Q_FLAG) == 0) {
discover_check_dir = 0;
} else {
direction_t king_dir = king_atk->relative_direction;
square_t sq;
for (sq = from+king_dir; pos->board[sq] == EMPTY; sq+=king_dir) {}
if (sq == king_sq) {
// Nothing between us and the king. Is there anything
// behind us to do the check when we move?
for (sq = from-king_dir; pos->board[sq] == EMPTY;
sq -= king_dir) {}
if (side == piece_color(pos->board[sq]) &&
(king_atk->possible_attackers &
get_piece_flag(pos->board[sq]))) {
discover_check_dir = king_dir;
}
}
}
// Generate checking moves.
will_discover_check = discover_check_dir && abs(discover_check_dir)!=N;
to = from + pawn_push[side];
if (pos->board[to] != EMPTY) continue;
rank_t r_rank =
relative_rank[side][square_rank(from)];
if (r_rank == RANK_7) continue; // non-promotes only
for (const direction_t* delta = piece_deltas[piece]; *delta; ++delta) {
if (will_discover_check || to + *delta == king_sq) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
break;
}
}
to += pawn_push[side];
if (r_rank == RANK_2 && pos->board[to] == EMPTY) {
for (const direction_t* delta = piece_deltas[piece];
*delta; ++delta) {
if (will_discover_check || to + *delta == king_sq) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
break;
}
}
}
}
for (int i = 0; i < pos->num_pieces[side]; ++i) {
square_t from = pos->pieces[side][i];
square_t to = INVALID_SQUARE;
piece_t piece = pos->board[from];
// Figure out whether or not we can discover check by moving.
direction_t discover_check_dir = 0;
bool will_discover_check;
const attack_data_t* king_atk = &get_attack_data(from, king_sq);
if ((king_atk->possible_attackers & Q_FLAG) == 0) {
discover_check_dir = 0;
} else {
direction_t king_dir = king_atk->relative_direction;
square_t sq;
for (sq = from+king_dir; pos->board[sq] == EMPTY; sq+=king_dir) {}
if (sq == king_sq) {
// Nothing between us and the king. Is there anything
// behind us to do the check when we move?
for (sq = from - king_dir; pos->board[sq] == EMPTY;
sq -= king_dir) {}
if (side == piece_color(pos->board[sq]) &&
(king_atk->possible_attackers &
get_piece_flag(pos->board[sq]))) {
discover_check_dir = king_dir;
}
}
}
// Generate checking moves.
if (piece_is_type(piece, KNIGHT)) {
for (const direction_t* delta = piece_deltas[piece];
*delta; ++delta) {
to = from + *delta;
if (pos->board[to] != EMPTY) continue;
if (discover_check_dir ||
possible_attack(to, king_sq, WN)) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
}
}
} else {
for (const direction_t* delta = piece_deltas[piece];
*delta; ++delta) {
for (to = from+*delta; pos->board[to] == EMPTY; to+=*delta) {
will_discover_check = discover_check_dir &&
abs(discover_check_dir) != abs(*delta);
if (will_discover_check) {
moves = add_move(pos,
create_move(from, to, piece, NONE),
moves);
continue;
}
if (possible_attack(to, king_sq, piece)) {
const direction_t to_king = direction(to, king_sq);
square_t x = to + to_king;
for (; pos->board[x] == EMPTY; x+=to_king) {}
if (x == king_sq) {
moves = add_move(pos,
create_move(from, to, piece, NONE),
moves);
}
}
}
}
}
}
*moves = 0;
return moves-moves_head;
}
/*
* Generate all moves that evade check in the given position. This is purely
* legal move generation; no pseudo-legal moves.
*/
int generate_evasions(const position_t* pos, move_t* moves)
{
assert(pos->is_check && pos->board[pos->check_square]);
move_t* moves_head = moves;
color_t side = pos->side_to_move, other_side = side^1;
square_t king_sq = pos->pieces[side][0];
square_t check_sq = pos->check_square;
piece_t king = create_piece(side, KING);
piece_t checker = pos->board[check_sq];
// Generate king moves.
// Don't let the king mask its possible destination squares in calls
// to is_square_attacked.
square_t from = king_sq, to = INVALID_SQUARE;
((position_t*)pos)->board[king_sq] = EMPTY;
for (const direction_t* delta = piece_deltas[king]; *delta; ++delta) {
to = from + *delta;
piece_t capture = pos->board[to];
if (capture != EMPTY && !can_capture(king, capture)) continue;
if (is_square_attacked((position_t*)pos,to,other_side)) continue;
((position_t*)pos)->board[king_sq] = king;
moves = add_move(pos, create_move(from, to, king, capture), moves);
((position_t*)pos)->board[king_sq] = EMPTY;
}
((position_t*)pos)->board[king_sq] = king;
// If there are multiple checkers, only king moves are possible.
if (pos->is_check > 1) {
*moves = 0;
return moves-moves_head;
}
// First, the most common case: a check that can be evaded via an
// en passant capture. Note that if we're in check and an en passant
// capture is available, the only way the en passant capture would evade
// the check is if it's the newly moved pawn that's checking us.
direction_t pin_dir;
if (pos->ep_square != EMPTY &&
check_sq+pawn_push[side] == pos->ep_square &&
pos->board[pos->ep_square] == EMPTY) {
piece_t our_pawn = create_piece(side, PAWN);
to = pos->ep_square;
for (int i=0; i<2; ++i) {
from = to-piece_deltas[our_pawn][i];
if (pos->board[from] && pos->board[from] == our_pawn) {
pin_dir = pin_direction(pos, from, king_sq);
if (pin_dir) continue;
moves = add_move(pos,
create_move_enpassant(from, to, our_pawn, checker),
moves);
}
}
}
// Generate captures of the checker.
for (int i = 0; i < pos->num_pawns[side]; ++i) {
from = pos->pawns[side][i];
piece_t piece = create_piece(side, PAWN);
pin_dir = pin_direction(pos, from, king_sq);
if (pin_dir) continue;
if (!possible_attack(from, check_sq, piece)) continue;
if (relative_rank[side][square_rank(from)] == RANK_7) {
// Capture and promote.
for (piece_t promoted=QUEEN; promoted > PAWN; --promoted) {
moves = add_move(pos,
create_move_promote(from, check_sq, piece,
checker, promoted),
moves);
}
} else {
moves = add_move(pos,
create_move(from, check_sq, piece, checker),
moves);
}
}
for (int i = 1; i < pos->num_pieces[side]; ++i) {
from = pos->pieces[side][i];
piece_t piece = pos->board[from];
pin_dir = pin_direction(pos, from, king_sq);
if (pin_dir) continue;
if (!possible_attack(from, check_sq, piece)) continue;
if (piece_slide_type(piece) == NONE) {
moves = add_move(pos,
create_move(from, check_sq, piece, checker),
moves);
} else {
// A sliding piece, keep going until we hit something.
direction_t check_dir = direction(from, check_sq);
for (to=from+check_dir; pos->board[to] == EMPTY; to+=check_dir) {}
if (to == check_sq) {
moves = add_move(pos,
create_move(from, to, piece, checker),
moves);
continue;
}
}
}
if (piece_slide_type(checker) == NONE) {
*moves = 0;
return moves-moves_head;
}
// A slider is doing the checking; generate blocking moves.
direction_t block_dir = direction(check_sq, king_sq);
for (int i = 0; i < pos->num_pawns[side]; ++i) {
from = pos->pawns[side][i];
piece_t piece = create_piece(side, PAWN);
direction_t k_dir;
pin_dir = pin_direction(pos, from, king_sq);
if (pin_dir) continue;
to = from + pawn_push[side];
if (pos->board[to] != EMPTY) continue;
rank_t rank = relative_rank[side][square_rank(from)];
k_dir = direction(to, king_sq);
if (k_dir == block_dir &&
((king_sq < to && check_sq > to) ||
(king_sq > to && check_sq < to))) {
if (rank == RANK_7) {
// Block and promote.
for (piece_t promoted=QUEEN; promoted > PAWN; --promoted) {
moves = add_move(pos,
create_move_promote(from, to, piece, EMPTY, promoted),
moves);
}
} else {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
}
}
if (rank != RANK_2) continue;
to += pawn_push[side];
if (pos->board[to]) continue;
k_dir = direction(to, king_sq);
if (k_dir == block_dir &&
((king_sq < to && check_sq > to) ||
(king_sq > to && check_sq < to))) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
}
}
for (int i=1; i<pos->num_pieces[side]; ++i) {
from = pos->pieces[side][i];
piece_t piece = pos->board[from];
direction_t k_dir;
pin_dir = pin_direction(pos, from, king_sq);
if (pin_dir) continue;
if (piece_is_type(piece, KNIGHT)) {
for (const direction_t* delta=piece_deltas[piece];
*delta; ++delta) {
to = from + *delta;
if (pos->board[to] != EMPTY) continue;
k_dir = direction(to, king_sq);
if (k_dir == block_dir &&
((king_sq < to && check_sq > to) ||
(king_sq > to && check_sq < to))) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
}
}
} else {
for (const direction_t* delta=piece_deltas[piece];
*delta; ++delta) {
for (to = from+*delta; pos->board[to] == EMPTY; to+=*delta) {
k_dir = direction(to, king_sq);
if (k_dir == block_dir &&
((king_sq < to && check_sq > to) ||
(king_sq > to && check_sq < to))) {
moves = add_move(pos,
create_move(from, to, piece, EMPTY),
moves);
break;
}
}
}
}
}
*moves = 0;
return moves-moves_head;
}
