Dynamic Extension

A dynamic extension is used when auxiliary data needs to be associated with the data object, such as a constraint or a callback function pointer. This is accomplished via the scv_smart_ptr template in the Verification Standard. 

For example, the following code generates a random value for an integer and register a callback.

The scv_shared_ptr template enables sharing of data objects among multiple C++ threads by performing automatic memory management. The scv_smart_ptr template combines scv_shared_ptr and scv_extensions to attach auxiliary data to a data object. The scv_smart_ptr subsumes the functionality in scv_shared_ptr, but scv_smart_ptr is more costly in both memory space and performance, so it should be used only when dynamic extensions are needed.
Example : scv_smart_ptr

  1 #include

  2

  3 class packet_t {

  4   public :

  5     sc_uint<8>  addr;

  6     sc_uint<12> data;

  7 };

  8

  9 SCV_EXTENSIONS(packet_t) {

 10   public:

 11     scv_extensions< sc_uint<8> > addr;

 12     scv_extensions< sc_uint<12> > data;

 13     SCV_EXTENSIONS_CTOR(packet_t) {

 14       SCV_FIELD(addr);

 15       SCV_FIELD(data);

 16     }

 17 };

 18

 19 void do_something (scv_smart_ptr p) {

 20   cout << "address : " << p->addr << endl;

 21   cout << "data : " << p->data << endl;

 22   if (p->data == 0) {

 23     p-> data = rand();

 24   }

 25   if (p-> addr == 0) {

 26     p-> addr = rand();

 27   }

 28   cout << "The whole packet : " << endl;

 29   p->print();

 30 };

 31

 32 int sc_main (int argc, char* argv[]) {

 33   scv_smart_ptr pkt_p("packet");

 34   do_something(pkt_p);

 35   return 0;

 36 }

Simulation Output : scv_smart_ptr
 address : 0

 data : 0

 The whole packet :

 {

   addr:54

   data:502

 }

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