Warning: (W571) no activity or clock movement for sc_start()

[omaima]

I'm trying to create vcd file for data gate and I got on this :

 

Info: (I703) tracing timescale unit set: 1 ns (trace.vcd)

Warning: (W571) no activity or clock movement for sc_start() invocation
In file: ../../../src/sysc/kernel/sc_simcontext.cpp:1742
 

my cod:

//andh.h file

#include <systemc.h>
SC_MODULE(andh){
    sc_in<bool> a;
    sc_in<bool> b;
    sc_out<bool> o;
    void and_process(){
        o.write(a.read()&&b.read());

    }
    SC_CTOR(andh){
        SC_METHOD(and_process);
        sensitive<<a<<b;

    }

};
////////////////////////////////////////////////////////////////////////////////////

andh.cpp file

#include<systemc.h>
#include"andh.h"
#define SC_MAKE_VERSION( x, y, z ) \
  (((x)*10000) + ((y)*100) + (z))

int sc_main(int argc, char*argv[]) {
    andh and1("and1");

    sc_signal<bool> A,B,O;

    and1.a(A);
    and1.b(B);
    and1.o(O);

    sc_start(SC_ZERO_TIME);

    sc_trace_file *tf=sc_create_vcd_trace_file("trace");

    tf->set_time_unit(1,SC_NS);

    sc_trace(tf,A,"A");
    sc_trace(tf,B,"B");
    sc_trace(tf,O,"O");

    A=0;B=0;

    sc_start(10,SC_MS);

    for(int i=0;i<10;i++){

        A=((i& 0x1)!=0);
        B=((i& 0x2)!=0);
        sc_start(10,SC_NS);
    }

    sc_close_vcd_trace_file(tf);
    sc_start();
    return 0;

}
///////////////////////////////////////////////////////////////////////////////////////////////

this is Warning message

[AmeyaVS]

Hello @omaima,

You probably want to replace the following lines:

31 minutes ago, omaima said:

sc_close_vcd_trace_file(tf);
    sc_start();

with:

sc_stop();
sc_close_vcd_trace_file(tf);

Also, I would recommend that you go through the examples folder in the SystemC sources to try and understand various modelling techniques.

Hope this helps.

Regards,

Ameya Vikram Singh

[Eyck]

You also need to change the order of sc_start and trace file creation:

    sc_trace_file *tf=sc_create_vcd_trace_file("trace");

    tf->set_time_unit(1,SC_NS);

    sc_trace(tf,A,"A");
    sc_trace(tf,B,"B");
    sc_trace(tf,O,"O"); 

    sc_start(SC_ZERO_TIME);

Afaik the kernel will not add traces once the simulation passed end of elaboration (which happens with the very first call of sc_start())