X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=6f8747635772aa930a604025bd5b0c95a67dbbc2;hp=55a4c4a2fa0e0ca56ae6fe3832a2649698ad3963;hb=7bdb8c9c5c82629f50252151afd542316665c505;hpb=262c380c4bf8dcadf07741ec458a9e6565ecf8b4

diff --git a/src/position.cpp b/src/position.cpp
index 55a4c4a2..6f874763 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -411,11 +411,14 @@ const string Position::pretty(Move move) const {
 }
 
 
-/// Position:hidden_checkers() returns a bitboard of all pinned / discovered check
-/// pieces, according to the call parameters. Pinned pieces protect our king and
-/// discovered check pieces attack the enemy king.
+/// Position::check_blockers() returns a bitboard of all the pieces with color
+/// 'c' that are blocking check on the king with color 'kingColor'. A piece
+/// blocks a check if removing that piece from the board would result in a
+/// position where the king is in check. A check blocking piece can be either a
+/// pinned or a discovered check piece, according if its color 'c' is the same
+/// or the opposite of 'kingColor'.
 
-Bitboard Position::hidden_checkers(Color c, Color kingColor) const {
+Bitboard Position::check_blockers(Color c, Color kingColor) const {
 
   Bitboard b, pinners, result = 0;
   Square ksq = king_square(kingColor);
@@ -1074,20 +1077,23 @@ int Position::see(Move m) const {
 
       // Add the new entry to the swap list
       swapList[slIndex] = -swapList[slIndex - 1] + PieceValue[MG][captured];
-      ++slIndex;
 
       // Locate and remove the next least valuable attacker
       captured = min_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers);
-      stm = ~stm;
-      stmAttackers = attackers & pieces(stm);
 
       // Stop before processing a king capture
-      if (captured == KING && stmAttackers)
+      if (captured == KING)
       {
-          swapList[slIndex++] = QueenValueMg * 16;
+          if (stmAttackers == attackers)
+              ++slIndex;
+
           break;
       }
 
+      stm = ~stm;
+      stmAttackers = attackers & pieces(stm);
+      ++slIndex;
+
   } while (stmAttackers);
 
   // Having built the swap list, we negamax through it to find the best