Remove some pointless micro-optimizations

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 9b5ab9234e8c506eb1e50446ba32faead5e37e7e..cd91b07fe773e5b9ba766d4055a36867c72b5c5f 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -34,10 +34,6 @@
 
 using std::string;
 
-Value PieceValue[PHASE_NB][PIECE_NB] = {
-{ VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg },
-{ VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } };
-
 namespace Zobrist {
 
   Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB];
@@ -159,42 +155,11 @@ void Position::init() {
 }
 
 
-/// 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) {
-
-  std::memcpy(this, &pos, sizeof(Position));
-  std::memcpy(&startState, st, sizeof(StateInfo));
-  st = &startState;
-  nodes = 0;
-
-  assert(pos_is_ok());
-
-  return *this;
-}
-
-
-/// Position::clear() erases the position object to a pristine state, with an
-/// empty board, white to move, and no castling rights.
-
-void Position::clear() {
-
-  std::memset(this, 0, sizeof(Position));
-  startState.epSquare = SQ_NONE;
-  st = &startState;
-
-  for (int i = 0; i < PIECE_TYPE_NB; ++i)
-      for (int j = 0; j < 16; ++j)
-          pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE;
-}
-
-
 /// Position::set() initializes the position object with the given FEN string.
 /// This function is not very robust - make sure that input FENs are correct,
 /// this is assumed to be the responsibility of the GUI.
 
-void Position::set(const string& fenStr, bool isChess960, Thread* th) {
+Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Thread* th) {
 /*
    A FEN string defines a particular position using only the ASCII character set.
 
@@ -234,7 +199,11 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) {
   Square sq = SQ_A8;
   std::istringstream ss(fenStr);
 
-  clear();
+  std::memset(this, 0, sizeof(Position));
+  std::memset(si, 0, sizeof(StateInfo));
+  std::fill_n(&pieceList[0][0][0], sizeof(pieceList) / sizeof(Square), SQ_NONE);
+  st = si;
+
   ss >> std::noskipws;
 
   // 1. Piece placement
@@ -295,6 +264,8 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) {
       if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN)))
           st->epSquare = SQ_NONE;
   }
+  else
+      st->epSquare = SQ_NONE;
 
   // 5-6. Halfmove clock and fullmove number
   ss >> std::skipws >> st->rule50 >> gamePly;
@@ -308,6 +279,8 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) {
   set_state(st);
 
   assert(pos_is_ok());
+
+  return *this;
 }
 
 
@@ -528,8 +501,7 @@ bool Position::legal(Move m, Bitboard pinned) const {
 
   // A non-king move is legal if and only if it is not pinned or it
   // is moving along the ray towards or away from the king.
-  return   !pinned
-        || !(pinned & from)
+  return   !(pinned & from)
         ||  aligned(from, to_sq(m), square<KING>(us));
 }
 
@@ -622,8 +594,7 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
       return true;
 
   // Is there a discovered check?
-  if (    ci.dcCandidates
-      && (ci.dcCandidates & from)
+  if (   (ci.dcCandidates & from)
       && !aligned(from, to, ci.ksq))
       return true;
 
@@ -1112,7 +1083,7 @@ void Position::flip() {
   std::getline(ss, token); // Half and full moves
   f += token;
 
-  set(f, is_chess960(), this_thread());
+  set(f, is_chess960(), st, this_thread());
 
   assert(pos_is_ok());
 }