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#define MOVES_INTERNAL
#include "engine/moves.h"
void get_king_moves(moves_t* moves, position_t position) {
assert_valid_position(position);
bitboard_t friendly_king;
int king_square;
bitboard_t friendly_pieces;
bitboard_t enemy_pieces;
if (position.turn == WHITE_TURN) {
friendly_pieces = whites(position);
enemy_pieces = blacks(position);
friendly_king = position.bitboards[WHITE_KING];
} else {
friendly_pieces = blacks(position);
enemy_pieces = whites(position);
friendly_king = position.bitboards[BLACK_KING];
}
king_square = __builtin_ctzll(friendly_king);
bitboard_t movement;
if (king_square >= 10) {
movement = 920078ULL << (king_square - 10);
} else {
movement = 920078ULL >> -(king_square - 10);
}
if (friendly_king & BITMASK_FILE_A) {
movement &= BITMASK_FILE_A | BITMASK_FILE_B;
} else if (friendly_king & BITMASK_FILE_H) {
movement &= BITMASK_FILE_G | BITMASK_FILE_H;
}
movement &= ~friendly_pieces;
while (movement) {
int to = __builtin_ctzll(movement);
movement &= movement - 1;
add_move(
moves,
king_square,
to,
.flags = ((enemy_pieces >> to) & 1) ? MOVE_CAPTURE : 0,
);
}
bitboard_t all_occupied = friendly_pieces | enemy_pieces;
if (position.turn == WHITE_TURN) {
if ((position.castling & WHITE_SHORT_CASTLE) &&
king_square == 4 &&
!((all_occupied >> 5) & 1) &&
!((all_occupied >> 6) & 1))
{
add_move(moves, 4, 6, .flags = MOVE_SHORT_CASTLE);
}
if ((position.castling & WHITE_LONG_CASTLE) &&
king_square == 4 &&
!((all_occupied >> 3) & 1) &&
!((all_occupied >> 2) & 1) &&
!((all_occupied >> 1) & 1))
{
add_move(moves, 4, 2, .flags = MOVE_LONG_CASTLE);
}
} else {
if ((position.castling & BLACK_SHORT_CASTLE) &&
king_square == 60 &&
!((all_occupied >> 61) & 1) &&
!((all_occupied >> 62) & 1))
{
add_move(moves, 60, 62, .flags = MOVE_SHORT_CASTLE);
}
if ((position.castling & BLACK_LONG_CASTLE) &&
king_square == 60 &&
!((all_occupied >> 59) & 1) &&
!((all_occupied >> 58) & 1) &&
!((all_occupied >> 57) & 1))
{
add_move(moves, 60, 58, .flags = MOVE_LONG_CASTLE);
}
}
}
#ifdef TEST_MOD
#include <stdbool.h>
bool test_white_king_corners() {
moves_t moves;
moves_init(&moves);
position_t p = {0};
p.bitboards[BLACK_KING] = 100;
p.bitboards[WHITE_KING] = 1;
p.turn = WHITE_TURN;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 0) return false;
if (moves.moves[0].to != 1) return false;
if (moves.moves[1].from != 0) return false;
if (moves.moves[1].to != 8) return false;
if (moves.moves[2].from != 0) return false;
if (moves.moves[2].to != 9) return false;
moves.length = 0;
p.bitboards[WHITE_KING] = 128;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 7) return false;
if (moves.moves[0].to != 6) return false;
if (moves.moves[1].from != 7) return false;
if (moves.moves[1].to != 14) return false;
if (moves.moves[2].from != 7) return false;
if (moves.moves[2].to != 15) return false;
moves.length = 0;
p.bitboards[WHITE_KING] = 72057594037927936ULL;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 56) return false;
if (moves.moves[0].to != 48) return false;
if (moves.moves[1].from != 56) return false;
if (moves.moves[1].to != 49) return false;
if (moves.moves[2].from != 56) return false;
if (moves.moves[2].to != 57) return false;
moves_deinit(moves);
return true;
}
bool test_black_king_corners() {
moves_t moves;
moves_init(&moves);
position_t p = {0};
p.bitboards[WHITE_KING] = 100;
p.bitboards[BLACK_KING] = 1;
p.turn = BLACK_TURN;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 0) return false;
if (moves.moves[0].to != 1) return false;
if (moves.moves[1].from != 0) return false;
if (moves.moves[1].to != 8) return false;
if (moves.moves[2].from != 0) return false;
if (moves.moves[2].to != 9) return false;
moves.length = 0;
p.bitboards[BLACK_KING] = 128;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 7) return false;
if (moves.moves[0].to != 6) return false;
if (moves.moves[1].from != 7) return false;
if (moves.moves[1].to != 14) return false;
if (moves.moves[2].from != 7) return false;
if (moves.moves[2].to != 15) return false;
moves.length = 0;
p.bitboards[BLACK_KING] = 72057594037927936ULL;
get_king_moves(&moves, p);
if (moves.length != 3) return false;
if (moves.moves[0].from != 56) return false;
if (moves.moves[0].to != 48) return false;
if (moves.moves[1].from != 56) return false;
if (moves.moves[1].to != 49) return false;
if (moves.moves[2].from != 56) return false;
if (moves.moves[2].to != 57) return false;
moves_deinit(moves);
return true;
}
#endif
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