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;
}