Author: James Swafford
Date: 10:25:08 11/30/04
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On November 30, 2004 at 12:51:38, Andrew N. Hunt wrote: >Hi! > >I've recently implemented bitboards (standard and rotated) and have a question >about pre-computing moves which contain blocked squares. Let's say I have the >occupied rank: > >bQ, wN, _, wR, _, bP, bN, _ > >and I want to find the valid moves for the white Rook. How do I handle modifying >its bitboard rank: 11010110 to remove the blocked squares and only store the >available squares: 01101100? (which I can then And with the white/black pieces >to find valid Rook moves) > >Maybe I'm missing something obvious... :-? You need to precompute a two dimension array Bitboard rank_moves[64][256]. The first index is the square the rook is on. The second index is the state of the rank (in this case 11010110 base 2). You'll need a similar array for files and diagonals (one for the a1->h8 direction and one more for the h1->a8 direction). Just build these arrays in your program initialization by doing some looping. Hope that helps... -- James > >Many thanks! > > > > > >ah. > >--------------------------------------------------------------------= >Andy Hunt >Manager, Electronic Documentation >Wolfram Research, Inc. >Voice: 217-398-0700 ext.260; Fax: 217-398-0747 >Email: andy@wolfram.com; http://www.wolfram.com/ >--------------------------------------------------------------------= > >Power corrupts. Absolute power is kind of neat. > -- John Lehman, Secretary of the Navy, 1981-1987
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