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Examples

Waiting semantics

The following example shows phase vs cycle waiting:

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//print Hello World 

module Top

    behavior
    $log<<endl<<"Hello World!!";$;
    end behavior
end module

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//Wait statements

module Top
    //wait
    submodule a : Wait 
end module

module Wait

    behavior
    $cout<<"\n time = "<<current_time;$;
    wait; //wait for one phase. Same as wait (0,1).
    $cout<<"\n time = "<<current_time;$;

    wait(2,0); //wait two cycles
    $cout<<"\n time = "<<current_time;$;

    wait(3,1); //wait 3 cycles and one phase
    $cout<<"\n time = "<<current_time;$;

    wait until (current_time==time(10,0));
    //wait until expression evaluates to true
     $cout<<"\n time = "<<current_time;$;
    end behavior
end module
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//A Shift register consists of a
//producer, connected to a consumer through 
//an array of shift register stages.
//The number of stages and delay of 
//each stage are parameters

module Top
    submodule S : ShiftRegister<3,2> 
    //Instantiate a shift register with <num_stages=3,delay=2>
end module

module ShiftRegister 
    parameter int N = 1     //number of stages
    parameter int DELAY = 1 //delay of each stage

    submodule p : Producer
    submodule c : Consumer
    submodule_array stage[N]  : Stage<DELAY>
    net_array n[N+1] : capacity 1

    //make connections
    for i in 0 to (N - 1)
        stage[i].ip <= n[i]
        stage[i].op => n[i+1]
    end for
    p.op => n[0]
    c.ip <= n[N]
end module

module Stage
    parameter   int     DELAY = 1  //delay of each stage
    inport      ip  
    outport     op  
    decl $token<> t; bool done_pull; bool done_push;$
behavior
    do
        //pull a token
        $done_pull=0;$;
        do
            wait until (this_phase==0);
            $done_pull=ip.pull(t);$;
            if(not done_pull) then wait end if;
        while(not done_pull) end do;
        $
        {
        cout<<"\n"<<std::setw(12)<<hierarchicalId();
        cout<<"\t pulled a token with ID "<<t.ID;
        cout<<" at time "<<current_time;
        }$;

        wait(DELAY,0);

        $done_push=0;$;
        do
            wait until (this_phase==1);
            $done_push=op.push(t);$;
            if(not done_push) then wait end if;
        while(not done_push) end do;
        $
        {
        cout<<"\n"<<std::setw(12)<<hierarchicalId();
        cout<<"\t pushed a token with ID "<<t.ID;
        cout<<" at time "<<current_time;
        }$;
    while(1) end do;
end behavior
end module

module Producer
    outport op 
    decl $token<> t; int count;$
    decl $static const int num_tokens=5;$ //total number of tokens produced
behavior 
    init$ count=0;$;
    do
        wait until (this_phase==1);
        //try to output as many tokens as possible
        $
        t.ID=count;
        while(op.push(t))
        {
            cout<<"\n"<<std::setw(12)<<hierarchicalId();
            cout<<"\t pushed a token with ID "<<t.ID;
            cout<<" at time "<<current_time;
            count ++;
            t.ID=count;
            if(count>=num_tokens) break;
        }
        $;
        wait;
    while (count<num_tokens) end do;
end behavior
end module

module Consumer
    inport ip 
    decl $token<> t; int count;$
behavior 
    init$ count=0;$;
    do
        wait until (this_phase==0);
        //try to pull as many tokens as possible

        $
        while(ip.pull(t))
        {
            cout<<"\n"<<std::setw(12)<<hierarchicalId();
            cout<<"\t pulled a token with ID "<<t.ID;
            cout<<" at time "<<current_time;
            count ++;
        }
        $;
        wait;
    while (1) end do;
end behavior
end module

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