stellar

0 #ifndef STELLAR_ATTACK_KNIGHT_H

1 #define STELLAR_ATTACK_KNIGHT_H

2

3 #include "bit.hpp"

4 #include "bitboard.hpp"

5 #include "square.hpp"

6 #include "utils.hpp"

7

8 #include <array>

9

10 namespace attack {

11 namespace knight {

12

13 static constexpr U64 mask(const square::Square square) {

14 U64 bitboard = C64(0), attacks = C64(0), tmp;

15

16 bit::set(bitboard, to_underlying(square));

17 tmp = bitboard::nortOne(bitboard::nortOne(bitboard));

18 attacks |= bitboard::westOne(tmp) | bitboard::eastOne(tmp);

19 tmp = bitboard::soutOne(bitboard::soutOne(bitboard));

20 attacks |= bitboard::westOne(tmp) | bitboard::eastOne(tmp);

21 tmp = bitboard::westOne(bitboard::westOne(bitboard));

22 attacks |= bitboard::soutOne(tmp) | bitboard::nortOne(tmp);

23 tmp = bitboard::eastOne(bitboard::eastOne(bitboard));

24 attacks |= bitboard::soutOne(tmp) | bitboard::nortOne(tmp);

25

26 return attacks;

27 }

28

29 typedef std::array<U64, 64> attack_array;

30 const attack_array attacks = []() -> attack_array {

31 std::array<U64, 64> attacks;

32 for (uint8_t square = 0; square < 64; square++)

33 attacks[square] = mask(static_cast<square::Square>(square));

34 return attacks;

35 }();

36

37 inline constexpr U64 attack(const square::Square square, U64 occupancy) {

38 return attacks[to_underlying(square)];

39 }

40

41 } // namespace knight

42 } // namespace attack

43

44 #endif