Debug and Trace Facilities in SystemC

1. Debug and Trace Facilities in SystemC Part of HW/SW Codesign of Embedded Systems Course (CE 40-226) Codesign of Embedded Systems

2. Today programme • Some SystemC examples • Simulation and Debugging in SystemC Codesign of Embedded Systems

3. display DFF d q Input_gen clock_gen DFF Example Codesign of Embedded Systems

4. DFF Example (cont’d) SC_MODULE(DFF) { sc_in<bool> d, clk; sc_out<bool> q; void update(); SC_CTOR(DFF){ SC_METHOD(update); sensitive_pos(clk); } }; display DFF d q Input_gen clock_gen void DFF::update() { q = d; cout <<"Time: “<< sc_time_stamp()<<". DFF: output updated to “<< q << endl; } Codesign of Embedded Systems

5. DFF Example (cont’d) SC_MODULE(input_gen){ sc_in<bool> clk; sc_out<bool> input_to_dff; sc_logic val; void gen() { input_to_dff = val; val = !val; cout<<"Time: ” <<sc_time_stamp() << ". input_gen: generating ” << input_to_dff<<" for next clock.\n"<<val;} display DFF d q Input_gen clock_gen SC_CTOR(input_gen) { SC_METHOD(gen); sensitive_pos(clk); val = 0; } }; Codesign of Embedded Systems

6. DFF Example (cont’d) SC_MODULE(display) { sc_in<bool> output_of_dff; void show() { cout<<"Time: "<< sc_time_stamp()<<". display: showing "<< output_of_dff<< endl; } SC_CTOR(display) { SC_METHOD(show); sensitive<<output_of_dff; } }; display DFF d q Input_gen clock_gen Codesign of Embedded Systems

7. DFF Example (cont’d) int sc_main(int , char*argv[]) { sc_clock clock_gen("CLK_GEN", 10, 0.5); sc_signal<bool> d, q; input_gen gen("Gen"); gen.clk(clock_gen.signal()); gen.input_to_dff(d); DFF ff("Flip Flop"); ff.clk(clock_gen); ff.d(d); ff.q(q); display DFF d q Input_gen clock_gen display disp("Disp"); disp.output_of_dff(q); sc_start(50); return 0; } Codesign of Embedded Systems

8. Simulation and Debugging Using SystemC • Simulation Control • Advanced Simulation Control Techniques • Tracing Waveforms • Creating The Trace File • Tracing Scalar Variable and Signals • Tracing Variables and Signals of Aggregate Types • Tracing Variable and Signal Arrays Codesign of Embedded Systems

9. Simulation and … (cont’d) • Simulation Control • sc_start(double simulation_duration) • sc_stop() • sc_time_stamp() • Debugging aid • read/print signal, port, and variable values • For ports and signals: The printed value is the current value, not the value just written to it Codesign of Embedded Systems

10. Simulation and … (cont’d) • Simulation Control • Advanced Simulation control techniques • Instead of sc_start: sc_initialize();// init SystemC scheduler // set signals by writing values to them sc_cycle(double); // simulates signal writes, then advances simulation time by its argument value Codesign of Embedded Systems

11. Simulation and … (cont’d) • Tracing Waveforms • Supported waveform formats • VCD (Value Change Dump) • ASCII WIF (Wave Intermediate Format) • ISDB (Integrated Signal DataBase) • Notes • Variables local to a function cannot be traced • scalar, array, and aggregate types can be traced • Different types of trace files can be created during the same simulation run • A signal or variable can be traced any number of times in different trace formats Codesign of Embedded Systems

12. Simulation and … (cont’d) • Tracing wave forms • Creating the trace file: sc_trace_file *tf; tf = sc_create_vcd_trace_file(“trace_file”); • For other trace file formats • sc_create_wif_trace_file(<filename>); • sc_create_isdb_trace_file(<filename>); • To close the trace file • sc_close_vcd_trace_file(<trace-file pointer>); • sc_close_wif_trace_file(<trace-file pointer>); • sc_close_isdb_trace_file(<trace-file pointer>); Codesign of Embedded Systems

13. Simulation and … (cont’d) • Tracing scalar variable and signals sc_trace(<trace-file pointer>, <traced variable>, <string>); • Example sc_signal<int> a; float b; sc_trace(trace_file, a, “MyA”); sc_trace(trace_file, b, “B”); Codesign of Embedded Systems

14. Simulation and … (cont’d) • Tracing variable and signals of aggregate type • Solution 1: trace each element separately • Solution 2: define a special trace function for the type • Will be covered later Codesign of Embedded Systems

15. Simulation and … (cont’d) • Tracing variable and signal arrays • Solution 1: trace each element separately • Solution 2: define a special trace function for the array • Will be covered later Codesign of Embedded Systems

16. What we learned today • More SystemC Examples • Simulation and Debugging using SystemC Codesign of Embedded Systems