From: lucasart <lucas.braesch@gmail.com>
Date: Tue, 30 Aug 2016 12:27:05 +0000 (+0800)
Subject: Change exclusion key setup
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=13b4444d9e3a3ac5a71f256145904d13754f9e7f

Change exclusion key setup

Should depend on which move is excluded. This
allow us to remove the dedicated Position::exclusion_key().

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 59814 W: 11136 L: 11083 D: 37595

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 31023 W: 4187 L: 4080 D: 22756

bench 7553379
---

diff --git a/src/position.cpp b/src/position.cpp
index bc8e92a1..aa06db08 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -40,11 +40,8 @@ namespace Zobrist {
   Key enpassant[FILE_NB];
   Key castling[CASTLING_RIGHT_NB];
   Key side;
-  Key exclusion;
 }
 
-Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion; }
-
 namespace {
 
 const string PieceToChar(" PNBRQK  pnbrqk");
@@ -132,7 +129,6 @@ void Position::init() {
   }
 
   Zobrist::side = rng.rand<Key>();
-  Zobrist::exclusion  = rng.rand<Key>();
 }
 
 
diff --git a/src/position.h b/src/position.h
index 7fce1dbb..c974f1bd 100644
--- a/src/position.h
+++ b/src/position.h
@@ -150,7 +150,6 @@ public:
   // Accessing hash keys
   Key key() const;
   Key key_after(Move m) const;
-  Key exclusion_key() const;
   Key material_key() const;
   Key pawn_key() const;
 
diff --git a/src/search.cpp b/src/search.cpp
index 7fafe933..c12f0862 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -622,7 +622,7 @@ namespace {
     // search to overwrite a previous full search TT value, so we use a different
     // position key in case of an excluded move.
     excludedMove = ss->excludedMove;
-    posKey = excludedMove ? pos.exclusion_key() : pos.key();
+    posKey = pos.key() ^ Key(excludedMove);
     tte = TT.probe(posKey, ttHit);
     ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
     ttMove =  rootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0]