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Retire move_attacks_square()

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There is only one call site. This patch is a
preparation for the next one that will affect
functionality.

No functional change.
This commit is contained in:
Marco Costalba 2012-10-30 19:56:19 +01:00
parent 13f90a30ef
commit 4e31c39a64
3 changed files with 23 additions and 42 deletions
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31
src/position.cpp
View file

@ -473,37 +473,6 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
}
/// Position::move_attacks_square() tests whether a move from the current
/// position attacks a given square.
bool Position::move_attacks_square(Move m, Square s) const {
assert(is_ok(m));
assert(is_ok(s));
Bitboard occ, xray;
Square from = from_sq(m);
Square to = to_sq(m);
Piece piece = piece_moved(m);
assert(!is_empty(from));
// Update occupancy as if the piece is moving
occ = pieces() ^ from ^ to;
// The piece moved in 'to' attacks the square 's' ?
if (attacks_from(piece, to, occ) & s)
return true;
// Scan for possible X-ray attackers behind the moved piece
xray = (attacks_bb< ROOK>(s, occ) & pieces(color_of(piece), QUEEN, ROOK))
| (attacks_bb<BISHOP>(s, occ) & pieces(color_of(piece), QUEEN, BISHOP));
// Verify attackers are triggered by our move and not already existing
return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
}
/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {

1
src/position.h
View file

@ -137,7 +137,6 @@ public:
// Properties of moves
bool move_gives_check(Move m, const CheckInfo& ci) const;
bool move_attacks_square(Move m, Square s) const;
bool move_is_legal(const Move m) const;
bool pl_move_is_legal(Move m, Bitboard pinned) const;
bool is_pseudo_legal(const Move m) const;

33
src/search.cpp
View file

@ -1411,12 +1411,10 @@ split_point_start: // At split points actual search starts from here
assert(!pos.is_capture_or_promotion(m));
assert(!pos.is_passed_pawn_push(m));
Square mfrom, mto, tfrom, tto;
mfrom = from_sq(m);
mto = to_sq(m);
tfrom = from_sq(threat);
tto = to_sq(threat);
Square mfrom = from_sq(m);
Square mto = to_sq(m);
Square tfrom = from_sq(threat);
Square tto = to_sq(threat);
// Case 1: Don't prune moves which move the threatened piece
if (mfrom == tto)
@ -1424,11 +1422,26 @@ split_point_start: // At split points actual search starts from here
// Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune moves which defend it.
if ( pos.is_capture(threat)
if ( pos.is_capture(threat)
&& ( PieceValue[MG][pos.piece_on(tfrom)] >= PieceValue[MG][pos.piece_on(tto)]
|| type_of(pos.piece_on(tfrom)) == KING)
&& pos.move_attacks_square(m, tto))
return true;
|| type_of(pos.piece_on(tfrom)) == KING))
{
// Update occupancy as if the piece is moving
Bitboard occ = pos.pieces() ^ mfrom ^ mto;
Piece piece = pos.piece_on(mfrom);
// The moved piece attacks the square 'tto' ?
if (pos.attacks_from(piece, mto, occ) & tto)
return true;
// Scan for possible X-ray attackers behind the moved piece
Bitboard xray = (attacks_bb< ROOK>(tto, occ) & pos.pieces(color_of(piece), QUEEN, ROOK))
| (attacks_bb<BISHOP>(tto, occ) & pos.pieces(color_of(piece), QUEEN, BISHOP));
// Verify attackers are triggered by our move and not already existing
if (xray && (xray ^ (xray & pos.attacks_from<QUEEN>(tto))))
return true;
}
// Case 3: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.