Compact position structures

gvreuls · snicolet · commit f233ca1af4d3 · 2021-05-22T00:26:00.000+02:00
Reorder the structures data members in position.h to reduce padding. Passed STC: https://tests.stockfishchess.org/tests/view/60a8011fce8ea25a3ef04069 LLR: 2.94 (-2.94,2.94) <-0.50,2.50> Total: 14120 W: 1214 L: 1067 D: 11839 Ptnml(0-2): 26, 857, 5161, 976, 40 --- Also tested for speed locally by Joost: Result of 50 runs ================== base (./stockfish.master ) = 2254919 +/- 4439 test (./stockfish.patch ) = 2274003 +/- 5278 diff = +19084 +/- 6386 ================== speedup = +0.0085 P(speedup > 0) = 1.0000 --- closes #3488 No functional change.
diff --git a/src/position.h b/src/position.h
@@ -51,11 +51,11 @@ struct StateInfo {
   // Not copied when making a move (will be recomputed anyhow)
   Key        key;
   Bitboard   checkersBB;
-  Piece      capturedPiece;
   StateInfo* previous;
   Bitboard   blockersForKing[COLOR_NB];
   Bitboard   pinners[COLOR_NB];
   Bitboard   checkSquares[PIECE_TYPE_NB];
+  Piece      capturedPiece;
   int        repetition;
 
   // Used by NNUE
@@ -192,11 +192,11 @@ class Position {
   int castlingRightsMask[SQUARE_NB];
   Square castlingRookSquare[CASTLING_RIGHT_NB];
   Bitboard castlingPath[CASTLING_RIGHT_NB];
+  Thread* thisThread;
+  StateInfo* st;
   int gamePly;
   Color sideToMove;
   Score psq;
-  Thread* thisThread;
-  StateInfo* st;
   bool chess960;
 };
 
