private function CanBlockCheckingPiece($nKingTile, $nAttackTile)
 {
     $this->nCalls++;
     // Get all tiles between the attacking piece and the king. Try to block one after the
     // other and test if making such a move gets us out of check. If a good move is found
     // return.
     $tiles = $this->GetTilesBetweenTwoTiles($this->floor[$nAttackTile], $nAttackTile % 8, $this->floor[$nKingTile], $nKingTile % 8);
     if (count($tiles) == 0) {
         return false;
     }
     foreach ($tiles as $nTile) {
         // See if any of the current player's pieces (except for the king) can move to this tile.
         if ($this->PlayerTurn == 0) {
             //bitmap = FindAttacksToTile(nTile / 8, nTile % 8) & ($this->n64WAll ^ $this->n64WKing);
             $bitmap = $this->FindMovesToTile($this->floor[$nTile], $nTile % 8)->_AND(BitBoard::_XOR_($this->n64WAll, $this->n64WKing));
         } else {
             //bitmap = FindAttacksToTile(nTile / 8, nTile % 8) & ($this->n64BAll ^ $this->n64BKing);
             $bitmap = $this->FindMovesToTile($this->floor[$nTile], $nTile % 8)->_AND(BitBoard::_XOR_($this->n64BAll, $this->n64BKing));
         }
         $tiles2 = $this->ChessUtils->GetTilesFromBitmap($bitmap);
         foreach ($tiles2 as $nSourceTile) {
             // Move the piece and if the king is no longer in check then all is good.
             $this->Board_MovePiece($nSourceTile % 8, $this->floor[$nSourceTile], $nTile % 8, $this->floor[$nTile]);
             if ($this->PlayerTurn == 0) {
                 $bitmap = $this->FindAttacksToTile($this->floor[$nKingTile], $nKingTile % 8)->_AND($this->n64BAll);
             } else {
                 $bitmap = $this->FindAttacksToTile($this->floor[$nKingTile], $nKingTile % 8)->_AND($this->n64WAll);
             }
             if ($bitmap->is_zero()) {
                 // Undo temp move.
                 $this->Board_MovePiece_($nTile % 8, $this->floor[$nTile], $nSourceTile % 8, $this->floor[$nSourceTile], $this->Board[$this->floor[$nSourceTile]][$nSourceTile % 8]);
                 return true;
             }
             // Undo temp move.
             $this->Board_MovePiece_($nTile % 8, $this->floor[$nTile], $nSourceTile % 8, $this->floor[$nSourceTile], $this->Board[$this->floor[$nSourceTile]][$nSourceTile % 8]);
         }
     }
     return false;
 }