template <typename addrT=int,typename valuT=int,typename stream_addrT=bm_addr,typename stream_sizeT=int64>

 class  stream_chip : public chip<addrT,valuT>{

 public:

     typedef  typename stream_addrT stream_addr_type;

     typedef  typename stream_sizeT stream_size_type; 

     stream_chip (bus_type * const owner, addr_type addr):chip<addrT,valuT>(owner,addr)

     {}

 public:

     virtual stream_size_type write_mem(stream_addr_type dest_addr, void* pValue ,stream_size_type size)=;  //write board memory

     virtual stream_size_type read_mem(void* pValue,stream_size_type size ,stream_addr_type src_addr)=;        //read bpard memory     

 };