#include "types.h"
-const Bitboard EmptyBoardBB = 0;
-
-const Bitboard FileABB = 0x0101010101010101ULL;
-const Bitboard FileBBB = FileABB << 1;
-const Bitboard FileCBB = FileABB << 2;
-const Bitboard FileDBB = FileABB << 3;
-const Bitboard FileEBB = FileABB << 4;
-const Bitboard FileFBB = FileABB << 5;
-const Bitboard FileGBB = FileABB << 6;
-const Bitboard FileHBB = FileABB << 7;
-
-const Bitboard Rank1BB = 0xFF;
-const Bitboard Rank2BB = Rank1BB << (8 * 1);
-const Bitboard Rank3BB = Rank1BB << (8 * 2);
-const Bitboard Rank4BB = Rank1BB << (8 * 3);
-const Bitboard Rank5BB = Rank1BB << (8 * 4);
-const Bitboard Rank6BB = Rank1BB << (8 * 5);
-const Bitboard Rank7BB = Rank1BB << (8 * 6);
-const Bitboard Rank8BB = Rank1BB << (8 * 7);
-
-extern Bitboard SquaresByColorBB[2];
extern Bitboard FileBB[8];
extern Bitboard NeighboringFilesBB[8];
extern Bitboard ThisAndNeighboringFilesBB[8];
}
+/// same_color_squares() returns a bitboard representing all squares with
+/// the same color of the given square.
+
+inline Bitboard same_color_squares(Square s) {
+ return bit_is_set(0xAA55AA55AA55AA55ULL, s) ? 0xAA55AA55AA55AA55ULL
+ : ~0xAA55AA55AA55AA55ULL;
+}
+
+
/// first_1() finds the least significant nonzero bit in a nonzero bitboard.
/// pop_1st_bit() finds and clears the least significant nonzero bit in a
/// nonzero bitboard.