Extensions for User-Specified Types
In order to support user-specified composite types, the user needs to provide a partial template specialization of scv_extensions for the specific composite type in the test bench.

Similar to the existing SystemC SC_MODULE macro, the SCV_EXTENSIONS and SCV_ENUM_EXTENSIONS macros create appropriate classes for the user-specified composite type and userspecified enumeration type.

The related macros in the SystemC Verification Standard to facilitate this process are summarized in the following table:

The scv_extensions Macros	Description
SCV_EXTENSIONS (type_name)	This macro is similar to SC_MODULE(). It defines the extension class for the composite type identified by type_name.
SCV_EXTENSIONS_CTOR (type_name)	This macro is similar to SC_CTOR(). It defines the constructor for the extension class of the composite type identified by type_name.
SCV_EXTENSIONS_ BASE_CLASS (base_type_name)	This macro declares base_type_name as the base class of the class to be extended. It must be instantiated within the block after SCV_EXTENSIONS_CTOR.
SCV_FIELD (field_name)	This macro declares a field identified by field_name. SCV_ENUM_EXTENSIONS(type_name) This macro is similar to SC_MODULE(). It defines the extension class for an enumeration identified by type_name.
SCV_ENUM_CTOR (type_name)	This macro is similar to SC_CTOR(). It defines the constructor for the extension class of the enumeration identified by type_name.
SCV_ENUM (enum_element_name)	This macro declares an enumeration element identified by enum_element_name.

Example : scv_user_defined

  1 #include 

  2 

  3 struct packet_t {

  4   sc_uint<8>  addr;

  5   sc_uint<12> data;

  6 };

  7 

  8 SCV_EXTENSIONS(packet_t) {

  9   public:

 10     scv_extensions< sc_uint<8> > addr;

 11     scv_extensions< sc_uint<12> > data;

 12     SCV_EXTENSIONS_CTOR(packet_t) {

 13       SCV_FIELD(addr);

 14       SCV_FIELD(data);

 15     }

 16 };

 17 

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

 19   packet_t  pkt; 

 20   pkt.addr = rand();

 21   pkt.data = rand();

 22   int bitwidth = scv_get_extensions(pkt.addr).get_bitwidth();

 23   cout << "Width of addr is "<< bitwidth << endl;

 24   bitwidth = scv_get_extensions(pkt.data).get_bitwidth();

 25   cout << "Width of data is "<< bitwidth << endl;

 26   scv_get_extensions(pkt).print();

 27   return 0;

28 }

Simulation Output : scv_user_defined

Width of addr is 8

 Width of data is 12

 {

   addr:103

   data:966

 }

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