From 95cfc0e3069e2bd573e37c42785a1d7b287295c2 Mon Sep 17 00:00:00 2001
From: Marco Costalba <mcostalba@gmail.com>
Date: Fri, 20 Feb 2009 10:20:08 +0100
Subject: [PATCH] In Position backup and restore contiguous data

Give the compiler one more chance to optimize the copy.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---
 src/position.cpp | 46 ++++++++++++++++++++++------------------------
 src/position.h   | 34 ++++++++++++++++++----------------
 2 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/src/position.cpp b/src/position.cpp
index fdf3e911..2fc73b66 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -678,24 +678,23 @@ bool Position::move_is_capture(Move m) const {
 
 void Position::backup(UndoInfo& u) const {
 
-  u.castleRights = castleRights;
-  u.epSquare     = epSquare;
-  u.checkersBB   = checkersBB;
-  u.key          = key;
-  u.pawnKey      = pawnKey;
-  u.materialKey  = materialKey;
-  u.rule50       = rule50;
-  u.lastMove     = lastMove;
-  u.mgValue      = mgValue;
-  u.egValue      = egValue;
-  u.capture      = NO_PIECE_TYPE;
-
   for (Color c = WHITE; c <= BLACK; c++)
   {
       u.pinners[c]      = pinners[c];
       u.pinned[c]       = pinned[c];
       u.dcCandidates[c] = dcCandidates[c];
   }
+  u.checkersBB   = checkersBB;
+  u.key          = key;
+  u.pawnKey      = pawnKey;
+  u.materialKey  = materialKey;
+  u.castleRights = castleRights;
+  u.rule50       = rule50;
+  u.epSquare     = epSquare;
+  u.lastMove     = lastMove;
+  u.mgValue      = mgValue;
+  u.egValue      = egValue;
+  u.capture      = NO_PIECE_TYPE;
 }
 
 
@@ -704,24 +703,23 @@ void Position::backup(UndoInfo& u) const {
 
 void Position::restore(const UndoInfo& u) {
 
-  castleRights = u.castleRights;
-  epSquare     = u.epSquare;
-  checkersBB   = u.checkersBB;
-  key          = u.key;
-  pawnKey      = u.pawnKey;
-  materialKey  = u.materialKey;
-  rule50       = u.rule50;
-  lastMove     = u.lastMove;
-  mgValue     = u.mgValue;
-  egValue     = u.egValue;
-  // u.capture is restored in undo_move()
-
   for (Color c = WHITE; c <= BLACK; c++)
   {
       pinners[c]      = u.pinners[c];
       pinned[c]       = u.pinned[c];
       dcCandidates[c] = u.dcCandidates[c];
   }
+  checkersBB   = u.checkersBB;
+  key          = u.key;
+  pawnKey      = u.pawnKey;
+  materialKey  = u.materialKey;
+  castleRights = u.castleRights;
+  rule50       = u.rule50;
+  epSquare     = u.epSquare;
+  lastMove     = u.lastMove;
+  mgValue     = u.mgValue;
+  egValue     = u.egValue;
+  // u.capture is restored in undo_move()
 }
 
 
diff --git a/src/position.h b/src/position.h
index 94b70033..02e3a245 100644
--- a/src/position.h
+++ b/src/position.h
@@ -74,17 +74,16 @@ enum CastleRights {
 
 
 /// The UndoInfo struct stores information we need to restore a Position
-/// object to its previous state when we retract a move.  Whenever a move
+/// object to its previous state when we retract a move. Whenever a move
 /// is made on the board (by calling Position::do_move), an UndoInfo object
-/// must be passed as a parameter.  When the move is unmade (by calling
+/// must be passed as a parameter. When the move is unmade (by calling
 /// Position::undo_move), the same UndoInfo object must be passed again.
 
 struct UndoInfo {
-  int castleRights;
-  Square epSquare;
-  Bitboard checkersBB, pinners[2], pinned[2], dcCandidates[2];
+  Bitboard pinners[2], pinned[2], dcCandidates[2], checkersBB;
   Key key, pawnKey, materialKey;
-  int rule50;
+  int castleRights, rule50;
+  Square epSquare;
   Move lastMove;
   Value mgValue, egValue;
   PieceType capture;
@@ -326,8 +325,6 @@ private:
 
   // Bitboards
   Bitboard byColorBB[2], byTypeBB[8];
-  Bitboard checkersBB;
-  mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
 
   // Board
   Piece board[64];
@@ -340,16 +337,21 @@ private:
   int index[64];
 
   // Other info
-  Color sideToMove;
-  int castleRights;
-  File initialKFile, initialKRFile, initialQRFile;
-  Square epSquare;
   Square kingSquare[2];
-  Move lastMove;
-  Key key, pawnKey, materialKey, history[MaxGameLength];
-  int rule50, gamePly;
-  Value mgValue, egValue;
+  Color sideToMove;
+  int gamePly;
+  Key history[MaxGameLength];
   Value npMaterial[2];
+  File initialKFile, initialKRFile, initialQRFile;
+
+  // Info backed up in do_move()
+  mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
+  Bitboard checkersBB;
+  Key key, pawnKey, materialKey;
+  int castleRights, rule50;
+  Square epSquare;
+  Move lastMove;
+  Value mgValue, egValue;
 
   // Static variables
   static int castleRightsMask[64];