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Code Issues Releases Wiki Activity

Use CheckInfo to generate checks

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It should help to avoid recalculating check squares
of sliding attackers for queen when already done for
bishops and rooks. Of course this helps when there are
bishop, rook and queen on the board !

Fixed also a subtle bug (use of same variable b in while
condition and in condition body) introduced recently by
revision d655147e8c that triggers
in case we have at least 2 non-pawn discovered check pieces.
This is very rare that's why didn't show in the node count
verification where we actually have a case of 2 dc pieces
in position 14, but one is a pawn.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2012-01-08 15:08:20 +01:00
parent 87fc9dcaa3
commit 9b43fd7937
3 changed files with 22 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

45
src/movegen.cpp
View file

@ -247,8 +247,8 @@ namespace {
template<PieceType Pt>
inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist,
Color us, const CheckInfo& ci) {
assert(Pt != KING && Pt != PAWN);
Bitboard checkSqs, b;
@ -258,7 +258,7 @@ namespace {
if ((from = *pl++) == SQ_NONE)
return mlist;
checkSqs = pos.attacks_from<Pt>(ksq) & pos.empty_squares();
checkSqs = ci.checkSq[Pt] & pos.empty_squares();
do
{
@ -267,7 +267,7 @@ namespace {
|| (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
continue;
if (dc && bit_is_set(dc, from))
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
continue;
b = pos.attacks_from<Pt>(from) & checkSqs;
@ -280,10 +280,11 @@ namespace {
template<>
FORCE_INLINE MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
FORCE_INLINE MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m,
Color us, const CheckInfo& ci) {
return us == WHITE ? generate_pawn_moves<WHITE, MV_NON_CAPTURE_CHECK>(p, m, dc, ksq)
: generate_pawn_moves<BLACK, MV_NON_CAPTURE_CHECK>(p, m, dc, ksq);
return us == WHITE ? generate_pawn_moves<WHITE, MV_NON_CAPTURE_CHECK>(p, m, ci.dcCandidates, ci.ksq)
: generate_pawn_moves<BLACK, MV_NON_CAPTURE_CHECK>(p, m, ci.dcCandidates, ci.ksq);
}
@ -383,37 +384,31 @@ MoveStack* generate<MV_NON_CAPTURE_CHECK>(const Position& pos, MoveStack* mlist)
assert(!pos.in_check());
Bitboard b, dc;
Square from;
PieceType pt;
Color us = pos.side_to_move();
Square ksq = pos.king_square(flip(us));
CheckInfo ci(pos);
Bitboard dc = ci.dcCandidates;
assert(pos.piece_on(ksq) == make_piece(flip(us), KING));
b = dc = pos.discovered_check_candidates();
while (b)
while (dc)
{
from = pop_1st_bit(&b);
pt = type_of(pos.piece_on(from));
Square from = pop_1st_bit(&dc);
PieceType pt = type_of(pos.piece_on(from));
if (pt == PAWN)
continue; // Will be generated togheter with direct checks
b = pos.attacks_from(Piece(pt), from) & pos.empty_squares();
Bitboard b = pos.attacks_from(Piece(pt), from) & pos.empty_squares();
if (pt == KING)
b &= ~QueenPseudoAttacks[ksq];
b &= ~QueenPseudoAttacks[ci.ksq];
SERIALIZE(b);
}
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);
mlist = generate_direct_checks<PAWN>(pos, mlist, us, ci);
mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, ci);
mlist = generate_direct_checks<BISHOP>(pos, mlist, us, ci);
mlist = generate_direct_checks<ROOK>(pos, mlist, us, ci);
mlist = generate_direct_checks<QUEEN>(pos, mlist, us, ci);
if (pos.can_castle(us))
{

2
src/position.cpp
View file

@ -79,7 +79,7 @@ namespace {
CheckInfo::CheckInfo(const Position& pos) {
Color them = flip(pos.side_to_move());
Square ksq = pos.king_square(them);
ksq = pos.king_square(them);
pinned = pos.pinned_pieces();
dcCandidates = pos.discovered_check_candidates();

1
src/position.h
View file

@ -37,6 +37,7 @@ struct CheckInfo {
Bitboard dcCandidates;
Bitboard pinned;
Bitboard checkSq[8];
Square ksq;
};