Raise penalty for knight attacked by pawn

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index a41dd52b66777aad041bfbd3bb914be8ff6c2f30..eda26014c32c49330a57cbdd996102a555011b0d 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -19,15 +19,15 @@
 
 #include <algorithm>
 #include <cassert>
-#include <cstring>
+#include <cstring>   // For std::memset
 #include <iomanip>
 #include <sstream>
 
 #include "bitcount.h"
+#include "misc.h"
 #include "movegen.h"
 #include "position.h"
 #include "psqtab.h"
-#include "misc.h"
 #include "thread.h"
 #include "tt.h"
 #include "uci.h"
@@ -47,7 +47,7 @@ namespace Zobrist {
   Key exclusion;
 }
 
-Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion;}
+Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion; }
 
 namespace {
 
@@ -123,7 +123,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) {
      << std::setfill('0') << std::setw(16) << pos.st->key << std::dec << "\nCheckers: ";
 
   for (Bitboard b = pos.checkers(); b; )
-      os << UCI::format_square(pop_lsb(&b)) << " ";
+      os << UCI::square(pop_lsb(&b)) << " ";
 
   return os;
 }
@@ -176,9 +176,8 @@ void Position::init() {
 }
 
 
-/// Position::operator=() creates a copy of 'pos'. We want the new born Position
-/// object to not depend on any external data so we detach state pointer from
-/// the source one.
+/// Position::operator=() creates a copy of 'pos' but detaching the state pointer
+/// from the source to be self-consistent and not depending on any external data.
 
 Position& Position::operator=(const Position& pos) {
 
@@ -444,7 +443,7 @@ const string Position::fen() const {
   if (!can_castle(WHITE) && !can_castle(BLACK))
       ss << '-';
 
-  ss << (ep_square() == SQ_NONE ? " - " : " " + UCI::format_square(ep_square()) + " ")
+  ss << (ep_square() == SQ_NONE ? " - " : " " + UCI::square(ep_square()) + " ")
      << st->rule50 << " " << 1 + (gamePly - (sideToMove == BLACK)) / 2;
 
   return ss.str();
@@ -642,7 +641,7 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
       return true;
 
   // Is there a discovered check?
-  if (   unlikely(ci.dcCandidates)
+  if (    ci.dcCandidates
       && (ci.dcCandidates & from)
       && !aligned(from, to, ci.ksq))
       return true;
@@ -691,10 +690,10 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
 void Position::do_move(Move m, StateInfo& newSt) {
 
   CheckInfo ci(*this);
-  do_move(m, newSt, ci, gives_check(m, ci));
+  do_move(m, newSt, gives_check(m, ci));
 }
 
-void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
+void Position::do_move(Move m, StateInfo& newSt, bool moveIsCheck) {
 
   assert(is_ok(m));
   assert(&newSt != st);
@@ -857,30 +856,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
   // Update the key with the final value
   st->key = k;
 
-  // Update checkers bitboard: piece must be already moved due to attacks_from()
-  st->checkersBB = 0;
-
-  if (moveIsCheck)
-  {
-      if (type_of(m) != NORMAL)
-          st->checkersBB = attackers_to(king_square(them)) & pieces(us);
-      else
-      {
-          // Direct checks
-          if (ci.checkSq[pt] & to)
-              st->checkersBB |= to;
-
-          // Discovered checks
-          if (unlikely(ci.dcCandidates) && (ci.dcCandidates & from))
-          {
-              if (pt != ROOK)
-                  st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(us, QUEEN, ROOK);
-
-              if (pt != BISHOP)
-                  st->checkersBB |= attacks_from<BISHOP>(king_square(them)) & pieces(us, QUEEN, BISHOP);
-          }
-      }
-  }
+  // Calculate checkers bitboard (if move is check)
+  st->checkersBB = moveIsCheck ? attackers_to(king_square(them)) & pieces(us) : 0;
 
   sideToMove = ~sideToMove;
 
@@ -1061,8 +1038,8 @@ Value Position::see(Move m) const {
   stm = color_of(piece_on(from));
   occupied = pieces() ^ from;
 
-  // Castling moves are implemented as king capturing the rook so cannot be
-  // handled correctly. Simply return 0 that is always the correct value
+  // Castling moves are implemented as king capturing the rook so cannot
+  // be handled correctly. Simply return VALUE_ZERO that is always correct
   // unless in the rare case the rook ends up under attack.
   if (type_of(m) == CASTLING)
       return VALUE_ZERO;