Clarify the mapping of files to queenside

Author: @nickpelling

We replace in the code the obscure expressions mapping files ABCDEFGH to ABCDDCBA
by an explicite call to an auxiliary function :

  old:   f = min(f, ~f)
  new:   f = map_to_queenside(f)

We used the Golbolt web site (https://godbolt.org) to find the optimal code
for the auxiliary function.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 30292 W: 6756 L: 6651 D: 16885
http://tests.stockfishchess.org/tests/view/5d8676720ebc5971531d6aa1

No functional change
This commit is contained in:
Stéphane Nicolet
2019-09-23 08:52:27 +02:00
parent 770c8d92f3
commit 7756344d5d
4 changed files with 7 additions and 3 deletions

View File

@@ -198,7 +198,7 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
b = theirPawns & file_bb(f);
int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
int d = std::min(f, ~f);
int d = map_to_queenside(f);
bonus += make_score(ShelterStrength[d][ourRank], 0);
if (ourRank && (ourRank == theirRank - 1))