Endgame evaluation

[Joost Buijs]

I use a 16 MB table which is indexed by the material hash, it contains a material scaling factor from 0 to 255%. Most entries are set at 100%, but for all these special cases I use a different percentage which tunes nicely with Texel style tuning. It handles all positions with max. 8P 3N 3B 3R 3Q for both sides, when the index falls out of this range I call a separate routine to handle this, but this does not happen very often.

It is material only, and I don't touch the positional evaluation, in practice it seems to work fine. My engine plays rather weak compared to others, basically it is a search problem, because the search is very ancient it doesn't look deep enough, the evaluation seems to be pretty well though.

The only weakness is king-safety, that could be better, when I have some time to spare I will try to improve this.