SystemC 35 Customized Data Type
sc_signal/fifo <T>
sc_signal<T> and sc_fifo<T> can be used with various data types. SystemC has already supported T for build-in data types.
In order to use customized data types for sc_signal and sc_fifo, the following member functions shall be implemented for the data type:
- assignment operator, i.e.
operator=(): needed for read and write methods - equality operator, i.e.
operator==(): needed bysc_signalforvalue_changed_event() - streaming output, i.e.
ostream& operator<<(): needed to print the data structure -
sc_trace(): allow the data type to be used with the systemC trace facility; enables viewing traced data with a wave for viewer.
Code
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// Learn with Examples, 2020, MIT license
#include <systemc>
#include <ostream>
using namespace sc_core;
struct CUSTOMIZED_TYPE {
int x, y; // member variables
CUSTOMIZED_TYPE(int x = 0, int y = 0) : x(x), y(y) {} // constructor
// Need (1) operatr=(), (2) operator==() inside the class declaration!
CUSTOMIZED_TYPE& operator=(const CUSTOMIZED_TYPE& rhs) { // assignment operator, needed for read() write()
x = rhs.x;
y = rhs.y;
return *this;
}
bool operator==(const CUSTOMIZED_TYPE& rhs) { // equality operator, needed for value_changed_event()
return x rhs.x && y rhs.y;
}
};
//(3) ostream$ operator<<(), (4) sc_trace() outside the class declaration!
std::ostream& operator<<(std::ostream& os, const CUSTOMIZED_TYPE& val) { // streaming output, needed for printing
os << "x = " << val.x << "; y = " << val.y << std::endl;
return os;
}
inline void sc_trace(sc_trace_file*& f, const CUSTOMIZED_TYPE& val, std::string name) { // needed for tracing
sc_trace(f, val.x, name + ".x");
sc_trace(f, val.y, name + ".y");
}
SC_MODULE(MODULE) { // test module
sc_signal<CUSTOMIZED_TYPE> s; // customized signal
SC_CTOR(MODULE) { // constructor
SC_THREAD(writer); // writer process
SC_THREAD(reader); // reader process
sensitive << s; // sensitive to customized signal s
dont_initialize();
}
void writer() {
int x = 1; // init signal
int y = 2;
while (true) {
s.write(CUSTOMIZED_TYPE{x++, y++}); // write to signal
wait(1, SC_SEC); // wait 1 s
}
}
void reader() {
while (true) {
std::cout << sc_time_stamp() << ": receives " << s.read() << std::endl; // read from signal
wait(); // wait for value_changed_event
}
}
};
int sc_main(int, char*[]) {
MODULE module("module"); // instantiate module
sc_trace_file* file = sc_create_vcd_trace_file("trace"); // open trace file
sc_trace(file, module.s, "customized_type"); // trace customized signal
sc_start(2, SC_SEC); // run simulation for 2 s
sc_close_vcd_trace_file(file); // close trace file
return 0;
}