An improvement to classic Chess4.5 style bitboards

[Michael Sherwin]

Classic bitboards get bits one ray at a time then ors them together into one complete bitboard. This process is not the slow part of bitboards. The slow part is then using BSF or BSR to make a move list out of them. An alternative to BSF would be to use the single (adjusted) ray bits as a pointer into a table of to-squares. One 64 bit integer unioned as 8 bytes is enough to store the number of to-squares in the ray as well as each to-square. So 64sq * 8dir * 8byte * 128 = 524,288 bytes max if I calculated correctly.