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stockfish
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Microptimize castling in undo_move() 

We don't need to set 'captured' and 'pt' after we
castle back.

No functional change.
pull/16/head
Marco Costalba 2014-03-15 11:21:47 +01:00
parent 36c381154b
commit 142874b058
1 changed files with 20 additions and 25 deletions
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45
src/position.cpp
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@ -863,7 +863,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
// Update the key with the final value
st->key = k;
// Update checkers bitboard: piece must be already moved
// Update checkers bitboard: piece must be already moved due to attacks_from()
st->checkersBB = 0;
if (moveIsCheck)
@ -877,7 +877,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
st->checkersBB |= to;
// Discovered checks
if (ci.dcCandidates && (ci.dcCandidates & from))
if (unlikely(ci.dcCandidates) && (ci.dcCandidates & from))
{
if (pt != ROOK)
st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(us, QUEEN, ROOK);
@ -904,24 +904,20 @@ void Position::undo_move(Move m) {
sideToMove = ~sideToMove;
Color us = sideToMove;
Color them = ~us;
Square from = from_sq(m);
Square to = to_sq(m);
PieceType pt = type_of(piece_on(to));
PieceType captured = st->capturedType;
assert(empty(from) || type_of(m) == CASTLING);
assert(captured != KING);
assert(st->capturedType != KING);
if (type_of(m) == PROMOTION)
{
PieceType promotion = promotion_type(m);
assert(promotion == pt);
assert(pt == promotion_type(m));
assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
assert(promotion_type(m) >= KNIGHT && promotion_type(m) <= QUEEN);
remove_piece(to, us, promotion);
remove_piece(to, us, promotion_type(m));
put_piece(to, us, PAWN);
pt = PAWN;
}
@ -930,28 +926,27 @@ void Position::undo_move(Move m) {
{
Square rfrom, rto;
do_castling<false>(from, to, rfrom, rto);
captured = NO_PIECE_TYPE;
pt = KING;
}
else
{
move_piece(to, from, us, pt); // Put the piece back at the source square
if (captured)
{
Square capsq = to;
if (type_of(m) == ENPASSANT)
if (st->capturedType)
{
capsq -= pawn_push(us);
Square capsq = to;
assert(pt == PAWN);
assert(to == st->previous->epSquare);
assert(relative_rank(us, to) == RANK_6);
assert(piece_on(capsq) == NO_PIECE);
if (type_of(m) == ENPASSANT)
{
capsq -= pawn_push(us);
assert(pt == PAWN);
assert(to == st->previous->epSquare);
assert(relative_rank(us, to) == RANK_6);
assert(piece_on(capsq) == NO_PIECE);
}
put_piece(capsq, ~us, st->capturedType); // Restore the captured piece
}
put_piece(capsq, them, captured); // Restore the captured piece
}
// Finally point our state pointer back to the previous state