chess:programming:bitboards
Differences
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| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| chess:programming:bitboards [2021/10/12 12:59] – peter | chess:programming:bitboards [2021/10/29 00:56] (current) – peter | ||
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| Line 2: | Line 2: | ||
| A BitBoard is comprised of a 64-bit word, which is used to store the positions of different Chess Pieces. | A BitBoard is comprised of a 64-bit word, which is used to store the positions of different Chess Pieces. | ||
| + | |||
| + | < | ||
| + | 8 0 0 0 0 0 0 0 0 | ||
| + | 7 0 0 0 0 0 0 0 0 | ||
| + | 6 0 0 0 0 0 0 0 0 | ||
| + | 5 0 0 0 0 0 0 0 0 | ||
| + | 4 0 0 0 0 0 0 0 0 | ||
| + | 3 0 0 0 0 0 0 0 0 | ||
| + | 2 0 0 0 0 0 0 0 0 | ||
| + | 1 0 0 0 0 0 0 0 0 | ||
| + | a b c d e f g h | ||
| + | </ | ||
| Every square on a Chess Board is represented by one bit in the 64-bit word. | Every square on a Chess Board is represented by one bit in the 64-bit word. | ||
| Line 122: | Line 134: | ||
| . . . 1 . 1 . . . . . . . . . . . . . . . . . . | . . . 1 . 1 . . . . . . . . . . . . . . . . . . | ||
| . . . 1 . . . . . . . . . . . . . . . . . . . . | . . . 1 . . . . . . . . . . . . . . . . . . . . | ||
| + | </ | ||
| + | |||
| + | ---- | ||
| + | |||
| + | ===== Determine Empty Squares ===== | ||
| + | |||
| + | The set of empty squares for instance is the complement-set of all occupied squares and vice versa: | ||
| + | |||
| + | < | ||
| + | ~occupied squares | ||
| + | 1 . 1 1 1 1 1 1 . 1 . . . . . . | ||
| + | 1 1 1 1 . 1 1 1 . . . . 1 . . . | ||
| + | . . 1 . . . . . 1 1 . 1 1 1 1 1 | ||
| + | . . . . 1 . . . 1 1 1 1 . 1 1 1 | ||
| + | ~ . . . . 1 . . . = 1 1 1 1 . 1 1 1 | ||
| + | . . . . . 1 . . 1 1 1 1 1 . 1 1 | ||
| + | 1 1 1 1 . 1 1 1 . . . . 1 . . . | ||
| + | 1 1 1 1 1 1 . 1 . . . . . . 1 . | ||
| + | </ | ||
| + | |||
| + | ---- | ||
| + | |||
| + | ===== Determine Squares which are exclusively set in one of the two sets ===== | ||
| + | |||
| + | Use XOR (Exclusive or). | ||
| + | |||
| + | < | ||
| + | 1 . . . . . . 1 . . . . . . . . 1 . . . . . . 1 | ||
| + | . 1 . . . . 1 . . . . . . . . . . 1 . . . . 1 . | ||
| + | . . 1 . . 1 . . . . 1 1 1 1 . . . . . 1 1 . . . | ||
| + | . . . 1 1 . . . . . 1 1 1 1 . . . . 1 . . 1 . . | ||
| + | . . . 1 1 . . . ^ . . 1 1 1 1 . . = . . 1 . . 1 . . | ||
| + | . . 1 . . 1 . . . . 1 1 1 1 . . . . . 1 1 . . . | ||
| + | . 1 . . . . 1 . . . . . . . . . . 1 . . . . 1 . | ||
| + | 1 . . . . . . 1 . . . . . . . . 1 . . . . . . 1 | ||
| + | </ | ||
| + | |||
| + | ---- | ||
| + | |||
| + | ===== Determine Squares which are set in both BitBoards ===== | ||
| + | |||
| + | Determine if one Bitboard is a subset of the other. | ||
| + | |||
| + | * Use xor (or subtraction). | ||
| + | |||
| + | < | ||
| + | super | ||
| + | . . . . . . . . . . . . . . . . . . . . . . . . | ||
| + | . 1 1 1 1 1 1 . . . . . . . . . . 1 1 1 1 1 1 . | ||
| + | . 1 1 1 1 1 1 . . . 1 1 1 1 . . . 1 . . . . 1 . | ||
| + | . 1 1 1 1 1 1 . ^ . . 1 1 1 1 . . . 1 . . . . 1 . | ||
| + | . 1 1 1 1 1 1 . . . 1 1 1 1 . . = . 1 . . . . 1 . | ||
| + | . 1 1 1 1 1 1 . - . . 1 1 1 1 . . . 1 . . . . 1 . | ||
| + | . 1 1 1 1 1 1 . . . . . . . . . . 1 1 1 1 1 1 . | ||
| + | . . . . . . . . . . . . . . . . . . . . . . . . | ||
| </ | </ | ||
chess/programming/bitboards.1634043572.txt.gz · Last modified: 2021/10/12 12:59 by peter