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Optimize check generation

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Because discovery checks are very rare it is better to handle
them all in one go and strip from usual check generation
function.

Also rewrite direct checks generation to use piece lists instead
of pop_1st_bit()

On perft test we have a +6% of speed up and is verified we
generate the same moves, although in a different order.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-11-01 10:40:14 +01:00
parent fa49311b36
commit 8ebe5075eb
1 changed files with 64 additions and 39 deletions
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93
src/movegen.cpp
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@ -80,12 +80,16 @@ namespace {
: generate_pawn_moves<BLACK, Type>(p, m));
}
// Template generate_piece_checks with specializations
// Templates for non-capture checks generation
template<PieceType Piece>
MoveStack* generate_discovered_checks(const Position& pos, Square from, MoveStack* mlist);
template<PieceType>
MoveStack* generate_piece_checks(const Position&, MoveStack*, Color, Bitboard, Square);
MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square);
template<>
inline MoveStack* generate_piece_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
inline MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
return (us == WHITE ? generate_pawn_moves<WHITE, CHECK>(p, m, dc, ksq)
: generate_pawn_moves<BLACK, CHECK>(p, m, dc, ksq));
@ -165,13 +169,28 @@ MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bi
assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
// Pieces moves
mlist = generate_piece_checks<PAWN>(pos, mlist, us, dc, ksq);
mlist = generate_piece_checks<KNIGHT>(pos, mlist, us, dc, ksq);
mlist = generate_piece_checks<BISHOP>(pos, mlist, us, dc, ksq);
mlist = generate_piece_checks<ROOK>(pos, mlist, us, dc, ksq);
mlist = generate_piece_checks<QUEEN>(pos, mlist, us, dc, ksq);
mlist = generate_piece_checks<KING>(pos, mlist, us, dc, ksq);
// Discovered non-capture checks
Bitboard b = dc;
while (b)
{
Square from = pop_1st_bit(&b);
switch (pos.type_of_piece_on(from))
{
case PAWN: /* Will be generated togheter with pawns direct checks */ break;
case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, from, mlist); break;
case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, from, mlist); break;
case ROOK: mlist = generate_discovered_checks<ROOK>(pos, from, mlist); break;
case KING: mlist = generate_discovered_checks<KING>(pos, from, mlist); break;
default: assert(false); break;
}
}
// Direct non-capture checks
mlist = generate_direct_checks<PAWN>(pos, mlist, us, dc, ksq);
mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, dc, ksq);
mlist = generate_direct_checks<BISHOP>(pos, mlist, us, dc, ksq);
mlist = generate_direct_checks<ROOK>(pos, mlist, us, dc, ksq);
mlist = generate_direct_checks<QUEEN>(pos, mlist, us, dc, ksq);
// Castling moves that give check. Very rare but nice to have!
if ( pos.can_castle_queenside(us)
@ -680,43 +699,49 @@ namespace {
}
template<PieceType Piece>
MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
MoveStack* generate_discovered_checks(const Position& pos, Square from, MoveStack* mlist) {
Bitboard target = pos.pieces(Piece, us);
assert(Piece != QUEEN);
// Discovered non-capture checks
Bitboard b = target & dc;
assert(Piece != QUEEN || !b);
while (b)
{
Square from = pop_1st_bit(&b);
Bitboard bb = pos.attacks_from<Piece>(from) & pos.empty_squares();
Bitboard b = pos.attacks_from<Piece>(from) & pos.empty_squares();
if (Piece == KING)
bb &= ~QueenPseudoAttacks[ksq];
SERIALIZE_MOVES(bb);
{
Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
b &= ~QueenPseudoAttacks[ksq];
}
SERIALIZE_MOVES(b);
return mlist;
}
// Direct non-capture checks
b = target & ~dc;
Bitboard checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
if (Piece != KING && checkSqs)
template<PieceType Piece>
MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
assert(Piece != KING);
Square from;
Bitboard checkSqs;
const Square* ptr = pos.piece_list_begin(us, Piece);
if ((from = *ptr++) == SQ_NONE)
return mlist;
checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
do
{
while (b)
{
Square from = pop_1st_bit(&b);
if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
|| (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
|| (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
continue;
if (dc && bit_is_set(dc, from))
continue;
Bitboard bb = pos.attacks_from<Piece>(from) & checkSqs;
SERIALIZE_MOVES(bb);
}
}
} while ((from = *ptr++) != SQ_NONE);
return mlist;
}