Introduce CheckInfo struct

Keeps info used to speed-up move_is_check()

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/position.cpp b/src/position.cpp
index 77a6d604523f40a841a5f73ba6a2e67e41a760f3..8ab712b46d1f81a0fe6cd25865f39a1ea57e3c93 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -56,12 +56,25 @@ Score Position::PieceSquareTable[16][64];
 
 static bool RequestPending = false;
 
 
 static bool RequestPending = false;
 

-////
-//// Functions
-////

 
 /// Constructors
 
 
 /// Constructors
 

+CheckInfo::CheckInfo(const Position& pos) {
+
+  Color us = pos.side_to_move();
+  Color them = opposite_color(us);
+
+  ksq = pos.king_square(them);
+  dc = pos.discovered_check_candidates(us);
+
+  checkSq[PAWN] = pos.attacks_from<PAWN>(ksq, them);
+  checkSq[KNIGHT] = pos.attacks_from<KNIGHT>(ksq);
+  checkSq[BISHOP] = pos.attacks_from<BISHOP>(ksq);
+  checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
+  checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
+  checkSq[KING] = EmptyBoardBB;
+}
+

 Position::Position(const Position& pos) {
   copy(pos);
 }
 Position::Position(const Position& pos) {
   copy(pos);
 }

diff --git a/src/position.h b/src/position.h
index 09c630062dd3984ea5a2fcc0ffaa647c7ff4fe2a..9e476722955a3f012bbf9c6f67a867db41d3078e 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -63,6 +63,18 @@ const int MaxGameLength = 220;
 //// Types
 ////
 
 //// Types
 ////
 

+/// struct checkInfo is initialized at c'tor time and keeps
+/// info used to detect if a move gives check.
+
+struct CheckInfo {
+
+    CheckInfo(const Position&);
+
+    Square ksq;
+    Bitboard dc;
+    Bitboard checkSq[8];
+};
+

 /// Castle rights, encoded as bit fields
 
 enum CastleRights {
 /// Castle rights, encoded as bit fields
 
 enum CastleRights {