Use special null move technique in low depth.

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index fd2bf037acdb2f6968647b43e0b2c6ff7cd10431..c5d057980c55fdf4320d088b308d307a6681e42b 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -829,6 +829,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) {
       set_bit(&(byTypeBB[promotion]), to);
       board[to] = piece_of_color_and_type(us, promotion);
 
+      // Update material key
+      st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
+      st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
+
       // Update piece counts
       pieceCount[us][PAWN]--;
       pieceCount[us][promotion]++;
@@ -845,10 +849,6 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) {
       key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
       st->pawnKey ^= zobrist[us][PAWN][to];
 
-      // Update material key
-      st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
-      st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
-
       // Partially revert and update incremental scores
       st->mgValue -= pst<MidGame>(us, PAWN, to);
       st->mgValue += pst<MidGame>(us, promotion, to);
@@ -886,6 +886,8 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) {
 
   st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
   st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+
+  assert(is_ok());
 }
 
 
@@ -953,7 +955,6 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ
 
 void Position::do_castle_move(Move m) {
 
-  assert(is_ok());
   assert(move_is_ok(m));
   assert(move_is_castle(m));
 
@@ -1042,6 +1043,8 @@ void Position::do_castle_move(Move m) {
 
   st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
   st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+
+  assert(is_ok());
 }
 
 
@@ -1146,6 +1149,8 @@ void Position::undo_move(Move m) {
 
   // Finally point our state pointer back to the previous state
   st = st->previous;
+
+  assert(is_ok());
 }
 
 
@@ -1210,6 +1215,8 @@ void Position::undo_castle_move(Move m) {
 
   // Finally point our state pointer back to the previous state
   st = st->previous;
+
+  assert(is_ok());
 }
 
 
@@ -1464,19 +1471,17 @@ void Position::clear() {
   memset(st, 0, sizeof(StateInfo));
   st->epSquare = SQ_NONE;
 
-  memset(index, 0, sizeof(int) * 64);
-  memset(byColorBB, 0, sizeof(Bitboard) * 2);
+  memset(byColorBB,  0, sizeof(Bitboard) * 2);
+  memset(byTypeBB,   0, sizeof(Bitboard) * 8);
+  memset(pieceCount, 0, sizeof(int) * 2 * 8);
+  memset(index,      0, sizeof(int) * 64);
 
   for (int i = 0; i < 64; i++)
       board[i] = EMPTY;
 
   for (int i = 0; i < 7; i++)
-  {
-      byTypeBB[i] = EmptyBoardBB;
-      pieceCount[0][i] = pieceCount[1][i] = 0;
       for (int j = 0; j < 8; j++)
           pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
-  }
 
   sideToMove = WHITE;
   gamePly = 0;