SEEをbitboardで高速化します！

とりあえず決意表明だけ(^^;

• BonanzaはSEEをbitboardで高速化しているらしい
• Craftyのswap.cがSEEである
• SEEは試行回数も多く、ちょっとした改良でもパフォーマンスが大幅に向上する

このへんは前々から思ってましたが、misaki(MC)のあまりの激遅ぶりに踏ん切りがつきました。
BonanzaのSEE処理もおそらくCraftyを参考にされてるはずだし。

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 *                                                                             *
 *   Swap() is used to analyze capture moves to see whether or not they appear *
 *   to be profitable.  the basic algorithm is extremely fast since it uses the*
 *   bitmaps to determine which squares are attacking the [target] square.     *
 *                                                                             *
 *   the algorithm is quite simple.  using the attack bitmaps, we enumerate all*
 *   the pieces that are attacking [target] for either side.  then we simply   *
 *   use the lowest piece (value) for the correct side to capture on [target]. *
 *   we continually "flip" sides taking the lowest piece each time.            *
 *                                                                             *
 *   as a piece is used, if it is a sliding piece (pawn, bishop, rook or queen)*
 *   we remove the piece, then generate moves of bishop/queen or rook/queen    *
 *   and then add those in to the attackers, removing any attacks that have    *
 *   already been used.                                                        *
 *                                                                             *
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