QSEARCH_RECAPTURES, QRECAPTURES
};
- // Our insertion sort, which is guaranteed to be stable, as it should be
- void insertion_sort(ExtMove* begin, ExtMove* end)
+ // An insertion sort, which sorts moves in descending order up to and including a given limit.
+ // The order of moves smaller than the limit is left unspecified.
+ // To keep the implementation simple, *begin is always included in the list of sorted moves.
+ void partial_insertion_sort(ExtMove* begin, ExtMove* end, Value limit)
{
- ExtMove tmp, *p, *q;
-
- for (p = begin + 1; p < end; ++p)
- {
- tmp = *p;
- for (q = p; q != begin && *(q-1) < tmp; --q)
- *q = *(q-1);
- *q = tmp;
- }
+ for (ExtMove *sortedEnd = begin + 1, *p = begin + 1; p < end; ++p)
+ if (p->value >= limit)
+ {
+ ExtMove tmp = *p, *q;
+ *p = *sortedEnd;
+ for (q = sortedEnd; q != begin && *(q-1) < tmp; --q)
+ *q = *(q-1);
+ *q = tmp;
+ ++sortedEnd;
+ }
}
// pick_best() finds the best move in the range (begin, end) and moves it to
cur = endBadCaptures;
endMoves = generate<QUIETS>(pos, cur);
score<QUIETS>();
- if (depth < 3 * ONE_PLY)
- {
- ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m)
- { return m.value > VALUE_ZERO; });
- insertion_sort(cur, goodQuiet);
- } else
- insertion_sort(cur, endMoves);
+
+ partial_insertion_sort(cur, endMoves,
+ depth < 3 * ONE_PLY ? VALUE_ZERO : Value(INT_MIN));
++stage;
case QUIET: