stellar

Occupancy bit count lookup table

1 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/ src/engine.c b/ src/engine.c

@@ -139,6 +139,30 @@ void bitboard_print(U64 bitboard) { /* ATTACKS */

// clang-format off

const int bishop_relavant_bits[] = {

6, 5, 5, 5, 5, 5, 5, 6,

5, 5, 5, 5, 5, 5, 5, 5,

5, 5, 7, 7, 7, 7, 5, 5,

5, 5, 7, 9, 9, 7, 5, 5,

5, 5, 7, 9, 9, 7, 5, 5,

5, 5, 7, 7, 7, 7, 5, 5,

5, 5, 5, 5, 5, 5, 5, 5,

6, 5, 5, 5, 5, 5, 5, 6,

};

const int rook_relavant_bits[] = {

12, 11, 11, 11, 11, 11, 11, 12,

11, 10, 10, 10, 10, 10, 10, 11,

11, 10, 10, 10, 10, 10, 10, 11,

11, 10, 10, 10, 10, 10, 10, 11,

11, 10, 10, 10, 10, 10, 10, 11,

11, 10, 10, 10, 10, 10, 10, 11,

11, 10, 10, 10, 10, 10, 10, 11,

12, 11, 11, 11, 11, 11, 11, 12,

};

// clang-format on

// pawn attack table [side][square] U64 pawn_attacks[2][64];

@@ -261,11 +285,13 @@ U64 set_occupancy(int index, int bits_in_mask, U64 attack_mask) { int main(void) { init_leapers_attacks();

U64 attack_mask = mask_rook_attacks(a1);

for (int i = 0; i < 4096; i++) {

U64 occupancy = set_occupancy(i, bit_count(attack_mask), attack_mask);

bitboard_print(occupancy);

getc(stdin);

for (int rank = 0; rank < 8; rank++) {

for (int file = 0; file < 8; file++) {

int square = rank * 8 + file;

/* printf("%d, ", bit_count(mask_bishop_attacks(square))); */

printf("%d, ", bit_count(mask_rook_attacks(square)));

}

printf("\n");

} return 0; }