Key posKey;
Move ttMove, move, excludedMove, bestMove, threatMove;
Depth ext, newDepth;
- Value bestValue, value, ttValue;
+ Value bestValue, value, ttValue, ttValueUpper;
Value eval, nullValue, futilityValue;
bool inCheck, givesCheck, pvMove, singularExtensionNode;
bool captureOrPromotion, dangerous, doFullDepthSearch;
tte = TT.probe(posKey);
ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
+ ttValueUpper = tte ? value_from_tt(tte->value_upper(), ss->ply) : VALUE_NONE;
// At PV nodes we check for exact scores, while at non-PV nodes we check for
// a fail high/low. Biggest advantage at probing at PV nodes is to have a
// smooth experience in analysis mode. We don't probe at Root nodes otherwise
// we should also update RootMoveList to avoid bogus output.
- if ( !RootNode
- && tte
- && tte->depth() >= depth
- && ttValue != VALUE_NONE // Only in case of TT access race
- && ( PvNode ? tte->type() == BOUND_EXACT
- : ttValue >= beta ? (tte->type() & BOUND_LOWER)
- : (tte->type() & BOUND_UPPER)))
+ if (!RootNode && tte)
{
- TT.refresh(tte);
- ss->currentMove = ttMove; // Can be MOVE_NONE
+ // Fail High
+ if ( (tte->type() & BOUND_LOWER)
+ && ttValue >= beta
+ && tte->depth() >= depth
+ && ttValue != VALUE_NONE) // Only in case of TT access race
+ {
+ // Update killers, we assume ttMove caused a cut-off
+ if ( ttMove
+ && !pos.is_capture_or_promotion(ttMove)
+ && ttMove != ss->killers[0])
+ {
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = ttMove;
+ }
+ TT.refresh(tte);
+ ss->currentMove = ttMove; // Can be MOVE_NONE
+ return ttValue;
+ }
- if ( ttValue >= beta
- && ttMove
- && !pos.is_capture_or_promotion(ttMove)
- && ttMove != ss->killers[0])
+ // Fail Low
+ if ( (tte->type() & BOUND_UPPER)
+ && ttValueUpper < beta
+ && tte->depth_upper() >= depth
+ && ttValueUpper != VALUE_NONE) // Only in case of TT access race
{
- ss->killers[1] = ss->killers[0];
- ss->killers[0] = ttMove;
+ TT.refresh(tte);
+ ss->currentMove = ttMove; // Can be MOVE_NONE
+ return ttValueUpper;
}
- return ttValue;
}
// Step 5. Evaluate the position statically and update parent's gain statistics
|| ((tte->type() & BOUND_UPPER) && ttValue < eval))
eval = ttValue;
}
-
- if (!tte)
- TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE,
- ss->staticEval, ss->evalMargin);
}
// Update gain for the parent non-capture move given the static position
if (bestValue >= beta) // Failed high
{
- TT.store(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER, depth,
- bestMove, ss->staticEval, ss->evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER, depth, bestMove);
if (!pos.is_capture_or_promotion(bestMove) && !inCheck)
{
else // Failed low or PV search
TT.store(posKey, value_to_tt(bestValue, ss->ply),
PvNode && bestMove != MOVE_NONE ? BOUND_EXACT : BOUND_UPPER,
- depth, bestMove, ss->staticEval, ss->evalMargin);
+ depth, bestMove);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
const TTEntry* tte;
Key posKey;
Move ttMove, move, bestMove;
- Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
- bool givesCheck, enoughMaterial, evasionPrunable;
+ Value bestValue, value, ttValue, ttValueUpper, futilityValue, futilityBase, oldAlpha;
+ bool givesCheck, enoughMaterial, evasionPrunable, fromNull;
Depth ttDepth;
// To flag BOUND_EXACT a node with eval above alpha and no available moves
ss->currentMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
+ fromNull = (ss-1)->currentMove == MOVE_NULL;
// Check for an instant draw or maximum ply reached
if (pos.is_draw<false, false>() || ss->ply > MAX_PLY)
tte = TT.probe(posKey);
ttMove = tte ? tte->move() : MOVE_NONE;
ttValue = tte ? value_from_tt(tte->value(),ss->ply) : VALUE_NONE;
+ ttValueUpper = tte ? value_from_tt(tte->value_upper(),ss->ply) : VALUE_NONE;
// Decide whether or not to include checks, this fixes also the type of
// TT entry depth that we are going to use. Note that in qsearch we use
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
: DEPTH_QS_NO_CHECKS;
- if ( tte
- && tte->depth() >= ttDepth
- && ttValue != VALUE_NONE // Only in case of TT access race
- && ( PvNode ? tte->type() == BOUND_EXACT
- : ttValue >= beta ? (tte->type() & BOUND_LOWER)
- : (tte->type() & BOUND_UPPER)))
+ if (tte)
{
- ss->currentMove = ttMove; // Can be MOVE_NONE
- return ttValue;
+ // Fail High
+ if ( (tte->type() & BOUND_LOWER)
+ && ttValue >= beta
+ && tte->depth() >= ttDepth
+ && ttValue != VALUE_NONE) // Only in case of TT access race
+ {
+ ss->currentMove = ttMove; // Can be MOVE_NONE
+ return ttValue;
+ }
+
+ // Fail Low
+ if ( (tte->type() & BOUND_UPPER)
+ && ttValueUpper < beta
+ && tte->depth_upper() >= ttDepth
+ && ttValueUpper != VALUE_NONE) // Only in case of TT access race
+ {
+ ss->currentMove = ttMove; // Can be MOVE_NONE
+ return ttValueUpper;
+ }
}
// Evaluate the position statically
}
else
{
- ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
+ if (fromNull)
+ {
+ // Approximated score. Real one is slightly higher due to tempo
+ ss->staticEval = bestValue = -(ss-1)->staticEval;
+ ss->evalMargin = VALUE_ZERO;
+ }
+ else
+ ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.key(), value_to_tt(bestValue, ss->ply), BOUND_LOWER,
- DEPTH_NONE, MOVE_NONE, ss->staticEval, ss->evalMargin);
+ TT.store(pos.key(), value_to_tt(bestValue, ss->ply), BOUND_LOWER, DEPTH_NONE, MOVE_NONE);
return bestValue;
}
// Futility pruning
if ( !PvNode
&& !InCheck
+ && !fromNull
&& !givesCheck
&& move != ttMove
&& enoughMaterial
}
else // Fail high
{
- TT.store(posKey, value_to_tt(value, ss->ply), BOUND_LOWER,
- ttDepth, move, ss->staticEval, ss->evalMargin);
-
+ TT.store(posKey, value_to_tt(value, ss->ply), BOUND_LOWER, ttDepth, move);
return value;
}
}
TT.store(posKey, value_to_tt(bestValue, ss->ply),
PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER,
- ttDepth, bestMove, ss->staticEval, ss->evalMargin);
+ ttDepth, bestMove);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
StateInfo state[MAX_PLY_PLUS_2], *st = state;
TTEntry* tte;
int ply = 0;
- Value v, m;
do {
tte = TT.probe(pos.key());
if (!tte || tte->move() != pv[ply]) // Don't overwrite correct entries
- {
- if (pos.in_check())
- v = m = VALUE_NONE;
- else
- v = evaluate(pos, m);
-
- TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply], v, m);
- }
+ TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply]);
assert(pos.move_is_legal(pv[ply]));
pos.do_move(pv[ply++], *st++);
projects / stockfish / blobdiff