bool ok_to_do_nullmove(const Position& pos);
bool ok_to_prune(const Position& pos, Move m, Move threat);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
+ Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
return value_from_tt(tte->value(), ply);
}
- approximateEval = quick_evaluate(pos);
+ approximateEval = refine_eval(tte, quick_evaluate(pos), ply);
isCheck = pos.is_check();
// Null move search
}
+ // refine_eval() returns the transposition table score if
+ // possible otherwise falls back on static position evaluation.
+
+ Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) {
+
+ if (!tte)
+ return defaultEval;
+
+ Value v = value_from_tt(tte->value(), ply);
+
+ if ( (is_lower_bound(tte->type()) && v >= defaultEval)
+ || (is_upper_bound(tte->type()) && v < defaultEval))
+ return v;
+
+ return defaultEval;
+ }
+
// update_history() registers a good move that produced a beta-cutoff
// in history and marks as failures all the other moves of that ply.