bitboard.h

#ifndef _BITBOARD_H_
#define _BITBOARD_H_

#include "shared.h"

enum {
    a8, b8, c8, d8, e8, f8, g8, h8,
    a7, b7, c7, d7, e7, f7, g7, h7,
    a6, b6, c6, d6, e6, f6, g6, h6,
    a5, b5, c5, d5, e5, f5, g5, h5,
    a4, b4, c4, d4, e4, f4, g4, h4,
    a3, b3, c3, d3, e3, f3, g3, h3,
    a2, b2, c2, d2, e2, f2, g2, h2,
    a1, b1, c1, d1, e1, f1, g1, h1, no_sq
};

#define get_bit(bb, square) ((bb) & (1ULL << (square)))
#define set_bit(bb, square) ((bb) |= (1ULL << (square)))
#define pop_bit(bb, square) ((bb) &= ~(1ULL << (square)))

static inline int count_bits(U64 bb) {
    int toRet = 0;
    while (bb) {
        ++toRet;
        bb &= bb -1;
    }
    return toRet;
}

static inline int get_ls1b_index(U64 bb) {
    if (bb) {
        return count_bits((bb & -bb) -1);
    } else {
        return -1;
    }
}

extern U64 bitboards[];
extern U64 occupancies[];
extern int side;
extern int enpassant;
extern int castle;

#endif  // _BITBOARD_H_