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Factor out pieceList updating code

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The new Position methods add_piece, move_piece, and remove_piece
now manage the member variables pieceList, pieceCount, and index,
and 9 blocks of code in Position that used to manipulate those
data structures by hand now call the new methods.

There is a slightly slowdown (< 1%) on Clang and on perft,
but the cleanup compensates the little speed loss.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Dan Schmidt
2013-07-29 11:44:58 -04:00
committed by Marco Costalba
parent 55948623e7
commit 7b4f5c8f72
2 changed files with 39 additions and 40 deletions
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26
src/position.h
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@@ -194,6 +194,9 @@ private:
// Helper functions
void do_castle(Square kfrom, Square kto, Square rfrom, Square rto);
Bitboard hidden_checkers(Square ksq, Color c) const;
void remove_piece(Square s, Color c, PieceType pt);
void add_piece(Square s, Color c, PieceType pt);
void move_piece(Square from, Square to, Color c, PieceType pt);
// Computing hash keys from scratch (for initialization and debugging)
Key compute_key() const;
@@ -414,4 +417,27 @@ inline Thread* Position::this_thread() const {
return thisThread;
}
inline void Position::add_piece(Square s, Color c, PieceType pt) {
index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
}
inline void Position::move_piece(Square from, Square to, Color c, PieceType pt) {
// index[from] is not updated and becomes stale. This works as long
// as index[] is accessed just by known occupied squares.
index[to] = index[from];
pieceList[c][pt][index[to]] = to;
}
inline void Position::remove_piece(Square s, Color c, PieceType pt) {
// WARNING: This is not a reversible operation. If we remove a piece in
// do_move() and then replace it in undo_move() we will put it at the end of
// the list and not in its original place, it means index[] and pieceList[]
// are not guaranteed to be invariant to a do_move() + undo_move() sequence.
Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]];
index[lastSquare] = index[s];
pieceList[c][pt][index[lastSquare]] = lastSquare;
pieceList[c][pt][pieceCount[c][pt]] = SQ_NONE;
}
#endif // #ifndef POSITION_H_INCLUDED