From: protonspring <mike@whiteley.org>
Date: Mon, 20 Aug 2018 16:29:46 +0000 (-0600)
Subject: make DistanceRing more consistent
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=8a4821923ac6860c791185a6d25c60ad0391739f;hp=8a4821923ac6860c791185a6d25c60ad0391739f;ds=sidebyside

make DistanceRing more consistent

This is a non-functional change. By pre-incrementing minKingPawnDistance
instead of post-incrementing, we can remove this -1.

This also makes DistanceRing more consistent with the rest of stockfish
since it now holds an actual "distance" instead of a less natural distance-1.

In current master, PseudoAttacks[KING][ksq] == DistanceRingBB[ksq][0]
With this patch, it will be PseudoAttacks[KING][ksq] == DistanceRingBB[ksq][1]
ie squares at distance 1 from the king. This is more natural use of distance.

The current array size DistanceRingBB[SQUARE_NB][8] is still OK with the new
definition, because maximum distance between two squares on a chess board is
seven (for example Kh1 and a8).

No functional change.
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