CACHE_LINE_ALIGNMENT
const uint8_t MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
- const uint8_t EvasionsPhaseTable[] = { PH_EVASIONS, PH_STOP};
+ const uint8_t EvasionsPhaseTable[] = { PH_TT_MOVES, PH_EVASIONS, PH_STOP};
const uint8_t QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
const uint8_t QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
}
const History& h, SearchStack* ss) : pos(p), H(h) {
int searchTT = ttm;
ttMoves[0].move = ttm;
- finished = false;
lastBadCapture = badCaptures;
- if (ss)
+ pinned = p.pinned_pieces(pos.side_to_move());
+
+ if (ss && !p.is_check())
{
ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
searchTT |= ttMoves[1].move;
} else
ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE;
- Color us = pos.side_to_move();
-
- dc = p.discovered_check_candidates(us);
- pinned = p.pinned_pieces(us);
-
if (p.is_check())
phasePtr = EvasionsPhaseTable;
else if (d > Depth(0))
- phasePtr = MainSearchPhaseTable + !searchTT;
+ phasePtr = MainSearchPhaseTable;
else if (d == Depth(0))
- phasePtr = QsearchWithChecksPhaseTable + !searchTT;
+ phasePtr = QsearchWithChecksPhaseTable;
else
- phasePtr = QsearchWithoutChecksPhaseTable + !searchTT;
+ {
+ phasePtr = QsearchWithoutChecksPhaseTable;
+
+ // Skip TT move if is not a capture or a promotion, this avoids
+ // qsearch tree explosion due to a possible perpetual check or
+ // similar rare cases when TT table is full.
+ if (ttm != MOVE_NONE && !pos.move_is_capture_or_promotion(ttm))
+ searchTT = ttMoves[0].move = MOVE_NONE;
+ }
- phasePtr--;
+ phasePtr += !searchTT - 1;
go_next_phase();
}
case PH_EVASIONS:
assert(pos.is_check());
lastMove = generate_evasions(pos, moves);
- score_evasions();
+ score_evasions_or_checks();
return;
case PH_QCAPTURES:
return;
case PH_QCHECKS:
- // Perhaps we should order moves move here? FIXME
- lastMove = generate_non_capture_checks(pos, moves, dc);
+ lastMove = generate_non_capture_checks(pos, moves);
+ score_evasions_or_checks();
return;
case PH_STOP:
- lastMove = curMove + 1; // hack to be friendly for get_next_move()
+ lastMove = curMove + 1; // Avoids another go_next_phase() call
return;
default:
Move m;
Piece piece;
Square from, to;
- int hs;
for (MoveStack* cur = moves; cur != lastMove; cur++)
{
from = move_from(m);
to = move_to(m);
piece = pos.piece_on(from);
- hs = H.move_ordering_score(piece, to);
-
- // Ensure history is always preferred to pst
- if (hs > 0)
- hs += 1000;
-
- // pst based scoring
- cur->score = hs + pos.pst_delta<Position::MidGame>(piece, from, to);
+ cur->score = H.move_ordering_score(piece, to);
}
}
-void MovePicker::score_evasions() {
- // Always try ttMove as first. Then try good captures ordered
- // by MVV/LVA, then non-captures if destination square is not
- // under attack, ordered by history value, and at the end
- // bad-captures and non-captures with a negative SEE. This
- // last group is ordered by the SEE score.
+void MovePicker::score_evasions_or_checks() {
+ // Try good captures ordered by MVV/LVA, then non-captures if
+ // destination square is not under attack, ordered by history
+ // value, and at the end bad-captures and non-captures with a
+ // negative SEE. This last group is ordered by the SEE score.
Move m;
int seeScore;
+ // Skip if we don't have at least two moves to order
+ if (lastMove < moves + 2)
+ return;
+
for (MoveStack* cur = moves; cur != lastMove; cur++)
{
m = cur->move;
- if (m == ttMoves[0].move)
- cur->score = 2 * HistoryMax;
- else if ((seeScore = pos.see_sign(m)) < 0)
+ if ((seeScore = pos.see_sign(m)) < 0)
cur->score = seeScore;
else if (pos.move_is_capture(m))
cur->score = pos.midgame_value_of_piece_on(move_to(m))
/// are no more moves left.
/// It picks the move with the biggest score from a list of generated moves taking
/// care not to return the tt move if has already been searched previously.
+/// Note that this function is not thread safe so should be lock protected by
+/// caller when accessed through a shared MovePicker object.
Move MovePicker::get_next_move() {
- assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP);
- assert( pos.is_check() || *phasePtr != PH_EVASIONS);
-
Move move;
while (true)
return move;
case PH_EVASIONS:
- move = pick_best(curMove++, lastMove).move;
- if (pos.pl_move_is_legal(move, pinned))
- return move;
- break;
-
case PH_QCAPTURES:
move = pick_best(curMove++, lastMove).move;
if ( move != ttMoves[0].move
}
}
-/// A variant of get_next_move() which takes a lock as a parameter, used to
-/// prevent multiple threads from picking the same move at a split point.
-
-Move MovePicker::get_next_move(Lock &lock) {
-
- lock_grab(&lock);
- if (finished)
- {
- lock_release(&lock);
- return MOVE_NONE;
- }
- Move m = get_next_move();
- if (m == MOVE_NONE)
- finished = true;
-
- lock_release(&lock);
- return m;
-}
projects / stockfish / blobdiff