DRAWSCORE

[chess]

Hello Simon,

I noticed the CVS change to the DRAWSCORE macro.

This fixes the sporadic Draw Bug which I was investigating.

Here's an amusing example:

[Event "Unrated game on a chess server"]
[White "GuestGnu506"]
[Black "Registered1600Player"]
[Result "1/2-1/2"]
[WhiteElo "0"]
[BlackElo "1600"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. O-O Bg4 6. c3 Ne7 7. d4 b5 8.
Bb3 f6 9. Ng5 Bxd1 10. Bf7+ Kd7 11. Be6+ Ke8 12. Bf7+ Kd7 13. Be6+ Ke8 14.
Bf7+ Kd7
{Game drawn by repetition} 1/2-1/2

The engine receives "rating 0 1600", and sacs the queen for a perpetual,
to achieve a score of 400. (1600-0)/4.

I was about to suggest that DRAWSCORE = 0 when either rating is zero.

But always zero is even better, since it furthers the goal of symmetrical 
evaluation.

Well Done !

*Mike