Module alcibiades::bitsets

Defines constants and functions for working with bitboards.

u64 bit-sets called bitboards can be used to represent a set of squares on the chessboard. This module defines utility functions and constants for working with u64 bit-sets.

Note: "LSB" means "least significant 1 bit".

Constants

BB_ALL	The set of all 64 squares on the board.
BB_FILE_A	The squares on file A.
BB_FILE_B	The squares on file B.
BB_FILE_C	The squares on file C.
BB_FILE_D	The squares on file D.
BB_FILE_E	The squares on file E.
BB_FILE_F	The squares on file F.
BB_FILE_G	The squares on file G.
BB_FILE_H	The squares on file H.
BB_MAIN_ANTI_DIAG	The squares on the main anti-diagonal (H1-A8).
BB_MAIN_DIAG	The squares on the main diagonal (A1-H8).
BB_NONE	Empty set of squares.
BB_RANK_1	The squares on rank 1.
BB_RANK_2	The squares on rank 2.
BB_RANK_3	The squares on rank 3.
BB_RANK_4	The squares on rank 4.
BB_RANK_5	The squares on rank 5.
BB_RANK_6	The squares on rank 6.
BB_RANK_7	The squares on rank 7.
BB_RANK_8	The squares on rank 8.

Functions

above_lsb	Returns a mask with all bits above the LSB set to 1.
above_lsb_including	Returns a mask with all bits above and including the LSB set to 1.
bb_anti_diag	Returns the set of squares on the same anti-diagonal as the given square.
bb_diag	Returns the set of squares on the same diagonal as the given square.
bb_file	Returns the set of squares on the same file as the given square.
bb_rank	Returns the set of squares on the same rank as the given square.
below_lsb	Returns a mask with all bits below the LSB set to 1.
below_lsb_including	Returns a mask with all bits below and including the LSB set to 1.
bsf	Returns the binary position of the LSB (bit-scan-forward).
bsf_reset	Returns the binary position of the LSB (bit-scan-forward), and resets the LSB to zero.
gen_shift	Shifts a value with a signed number.
lsb	Returns the LSB of a value.
pop_count	Returns the number of 1s in the binary representation of a value.
reset_lsb	Resets the LSB of a value to zero.