+// Note that operator< is set up such that sorting will be in descending order
+inline bool operator<(const MoveStack& f, const MoveStack& s) { return s.score < f.score; }
+
+// An helper insertion sort implementation
+template<typename T>
+inline void insertion_sort(T* firstMove, T* lastMove)
+{
+ T value;
+ T *cur, *p, *d;
+
+ if (firstMove != lastMove)
+ for (cur = firstMove + 1; cur != lastMove; cur++)
+ {
+ p = d = cur;
+ value = *p--;
+ if (value < *p)
+ {
+ do *d = *p;
+ while (--d != firstMove && value < *--p);
+ *d = value;
+ }
+ }
+}
+
+// Our dedicated sort in range [firstMove, lastMove), it is well
+// tuned for non-captures where we have a lot of zero scored moves.
+template<typename T>
+inline void sort_moves(T* firstMove, T* lastMove)
+{
+ T tmp;
+ T *p, *d;
+
+ d = lastMove;
+ p = firstMove - 1;
+
+ d->score = -1; // right guard
+
+ // Split positives vs non-positives
+ do {
+ while ((++p)->score > 0);
+
+ if (p != d)
+ {
+ while (--d != p && d->score <= 0);
+
+ tmp = *p;
+ *p = *d;
+ *d = tmp;
+ }
+
+ } while (p != d);
+
+ // Sort positives
+ insertion_sort<T>(firstMove, p);
+
+ d = lastMove;
+ p--;
+
+ // Split zero vs negatives
+ do {
+ while ((++p)->score == 0);
+
+ if (p != d)
+ {
+ while (--d != p && d->score < 0);
+
+ tmp = *p;
+ *p = *d;
+ *d = tmp;
+ }
+
+ } while (p != d);
+
+ // Sort negatives
+ insertion_sort<T>(p, lastMove);
+}
+
+// Picks up the best move in range [curMove, lastMove), one per cycle.
+// It is faster then sorting all the moves in advance when moves are few,
+// as normally are the possible captures. Note that is not a stable alghoritm.
+template<typename T>
+inline T pick_best(T* curMove, T* lastMove)
+{
+ T bestMove, tmp;
+
+ bestMove = *curMove;
+ while (++curMove != lastMove)
+ {
+ if (*curMove < bestMove)
+ {
+ tmp = *curMove;
+ *curMove = bestMove;
+ bestMove = tmp;
+ }
+ }
+ return bestMove;
+}