stellar

0 #ifndef STELLAR_BIT_H

1 #define STELLAR_BIT_H

2

3 #include "utils.hpp"

4

5 namespace bit {

6

7 inline constexpr bool get(const U64 &bitboard, uint8_t square) { return (bitboard >> (square)) & C64(1); }

8 inline constexpr void set(U64 &bitboard, uint8_t square) { bitboard |= (C64(1) << square); }

9 inline constexpr void pop(U64 &bitboard, uint8_t square) { bitboard &= ~(C64(1) << (square)); }

10

11 inline constexpr uint8_t count(U64 bitboard) {

12 #if __has_builtin(__builtin_popcountll)

13 return __builtin_popcountll(bitboard);

14 #else

15 int count = 0;

16 for (; bitboard > 0; bitboard &= bitboard - 1)

17 count++;

18 return count;

19 #endif

20 }

21

22 inline constexpr uint8_t lsb_index(U64 bitboard) {

23 #if __has_builtin(__builtin_ffsll)

24 return __builtin_ffsll(bitboard) - 1;

25 #else

26 if (!bitboard) return -1;

27 return bit_count((bitboard & -bitboard) - 1);

28 #endif

29 }

30

31 inline constexpr U64 &lsb_pop(U64 &bitboard) { return bitboard &= bitboard & (bitboard - 1); }

32

33 #define bitboard_for_each_bit(var, bb) \

34 for (var = bit::lsb_index(bb); bb; bit::lsb_pop(bb), var = bit::lsb_index(bb))

35

36 } // namespace bit

37

38 #endif