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SystemC supports many data types to communicate between 2 ports. eg: bool, unsigned char, unsigned int, sc_uint, … But, in some cases, we want to use a user-defined data type. In this post, we are going to discuss it.
Suppose, DUT_1 model needs some info of DUT_2 model. It is a group, ID, and address. Instead of, we declare 3 input ports for DUT_1 model corresponding 3 output ports of DUT_2 model, we will define an “extension_info” struct to store and information exchange between DUT_1 and DUT_2 model by 1 port.
It is the same as :
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struct extension_info { /// Constructor & Destructor extension_info(); ~extension_info(); /// Variables unsigned int group; unsigned int ID; unsigned int address; /// Functions void initialize(void); }; ... //output port sc_out <extension_info > output_p; ... //input port sc_in <extension_info > input_p; ... //bind port sc_signal<extension_info> signal_p; DUT_2->output_p(signal_p); DUT_1->input_p(signal_p); |
For extension_info works correct. We need :
- Overload “==” operator
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bool extension_info::operator == (const extension_info &indata) const { return ((this->group == indata.group) && (this->ID == indata.ID) && (this->address == indata.address)); } |
“==” operator using for judge value change or not in sc_signal_t::write( const T& value_ ) and sc_signal_t::update() functions (sc_signal.h)
- Overload “<<“ operator
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std::ostream& operator << (std::ostream& os,const extension_info& data) { os << "GROUP " <<": " << data.group << endl; os << "ID " <<": " << data.ID << endl; os << "ADDRESS " <<": 0x" <<std::hex<< (unsigned int) data.address << endl; return os; } |
“<<“ operator using in sc_signal_t::print( ::std::ostream& os ) const and sc_signal_t::dump( ::std::ostream& os ) const functions (sc_signal.h)
- Implement sc_trace function
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inline void sc_trace(sc_core::sc_trace_file* tf, const extension_info& data, const std::string& fn) { std::ostringstream str_tmp; str_tmp.str(""); str_tmp << "group"; sc_trace(tf, data.group, str_tmp.str().c_str()); str_tmp.str(""); str_tmp << "ID"; sc_trace(tf, data.ID, str_tmp.str().c_str()); str_tmp.str(""); str_tmp << "address"; sc_trace(tf, data.address, str_tmp.str().c_str()); } |
It is necessary for end_of_elaboration function (sc_signal_port.h)
And final, you can use extension_info as other data types for sc_in, sc_out, sc_signal… and using read(), write() function to read/write data.
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