Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
- return search<PvNode, false>(pos, ss, alpha, beta, depth, ply);
- }
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+
+ return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
+ : search<PvNode, false>(pos, ss, alpha, beta, depth, ply);
+ }
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
Key posKey;
Move ttMove, move, excludedMove, threatMove;
Depth ext, newDepth;
+ ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
threatMove = sp->threatMove;
mateThreat = sp->mateThreat;
goto split_point_start;
- }
+ } else {} // Hack to fix icc's "statement is unreachable" warning
// Step 1. Initialize node and poll. Polling can abort search
ThreadsMgr.incrementNodeCounter(threadID);
}
// Step 2. Check for aborted search and immediate draw
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return VALUE_DRAW;
-
- if (pos.is_draw() || ply >= PLY_MAX - 1)
+ if ( AbortSearch || ThreadsMgr.thread_should_stop(threadID)
+ || pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
// Step 3. Mate distance pruning
posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
tte = TT.retrieve(posKey);
- ttMove = (tte ? tte->move() : MOVE_NONE);
+ ttMove = tte ? tte->move() : MOVE_NONE;
// At PV nodes, we don't use the TT for pruning, but only for move ordering.
// This is to avoid problems in the following areas:
// * Fifty move rule detection
// * Searching for a mate
// * Printing of full PV line
-
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
- // Refresh tte entry to avoid aging
- TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->static_value_margin());
-
+ TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
-
- nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
&& (move = mp.get_next_move()) != MOVE_NONE
&& !ThreadsMgr.thread_should_stop(threadID))
{
+ assert(move_is_ok(move));
+
if (SpNode)
{
moveCount = ++sp->moveCount;
lock_release(&(sp->lock));
}
-
- assert(move_is_ok(move));
-
- if (move == excludedMove)
+ else if (move == excludedMove)
continue;
+ else
+ movesSearched[moveCount++] = move;
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
}
}
- newDepth = depth - ONE_PLY + ext;
-
// Update current move (this must be done after singular extension search)
- movesSearched[moveCount] = ss->currentMove = move;
-
- if (!SpNode)
- moveCount++;
+ ss->currentMove = move;
+ newDepth = depth - ONE_PLY + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (!SpNode && PvNode && moveCount == 1)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
else
{
// Step 14. Reduced depth search
{
alpha = SpNode ? sp->alpha : alpha;
Depth d = newDepth - ss->reduction;
- value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
doFullDepthSearch = (value > alpha);
}
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
// Step extra. pv search (only in PV nodes)
// Search only for possible new PV nodes, if instead value >= beta then
// parent node fails low with value <= alpha and tries another move.
if (PvNode && value > alpha && value < beta)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
threatMove, mateThreat, moveCount, &mp, PvNode);
}
- if (SpNode)
- {
- /* Here we have the lock still grabbed */
- sp->slaves[threadID] = 0;
- lock_release(&(sp->lock));
- return bestValue;
- }
-
// Step 19. Check for mate and stalemate
// All legal moves have been searched and if there are
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
- if (!moveCount)
+ if (!SpNode && !moveCount)
return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return bestValue;
+ if (!SpNode && !AbortSearch && !ThreadsMgr.thread_should_stop(threadID))
+ {
+ move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
+ vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
+ : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
- TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
- // Update killers and history only for non capture moves that fails high
- if ( bestValue >= beta
- && !pos.move_is_capture_or_promotion(move))
- {
+ // Update killers and history only for non capture moves that fails high
+ if ( bestValue >= beta
+ && !pos.move_is_capture_or_promotion(move))
+ {
update_history(pos, move, depth, movesSearched, moveCount);
update_killers(move, ss);
+ }
+ }
+
+ if (SpNode)
+ {
+ // Here we have the lock still grabbed
+ sp->slaves[threadID] = 0;
+ lock_release(&(sp->lock));
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);