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bitmaps |
 | | Then for each square, we initialize the rank_attacks[square][rank_contents] to the bitmap that matches the squares that a rook/queen on "square" could move to, assuming the rank is occupied as per the eight bit value "rank_contents". |
 | | For example, take the occupied_squares bitmap used earlier, but add a rook on square F5 instead of a bishop as in the previous example (figure 8), and assume we are trying to initialize rank_attacks[37][100] (37 is the square F5, and 100 represents the occupied squares on that rank, 01100100). |
 | | Perhaps the primary performance improvement to using bitmaps came from the Crafty project however, when the concept of "rotated bitmaps" was developed as an alternative to the classic incremental update approach used in chess 4.0, because this produced a substantial performance increase with no loss at all in capability. |
| www.cis.uab.edu /hyatt/bitmaps.html (5018 words) |
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