generate block

[IChip]

Hi experts,

I want to write several forever blocks dynamically.

Just like:

fork
   forever begin
       e[0].wait_on();
       seq[0].start(agents[0].sequencer);
       e[0].reset();
   end

   forever begin
       e[1].wait_on();
       seq[1].start(agents[1].sequencer);
       e[1].reset();
   end

   ...
join

Then I want to use generate block to replace mass codes above and make it configurable.

for(genvar i=0 ;i< NUM; i++)
  forever begin
       e[i].wait_on();
       seq[i].start(agents[i].sequencer);
       e[i].reset();
  end

But compile error:

Verilog keyword 'genvar' is not expected to be used in this context.

How can i use generate block in a class context??

Thanks

[dave_59]

You don't need to use generate block to do what you want:

for(int i=0 ;i< NUM; i++)
   fork
     int j=i; // each process needs a separate copy of 'i'
     forever begin
        e[i].wait_on();
        seq[i].start(agents[i].sequencer);
        e[i].reset();
     end
  join_none
wait fork; // waits forever

Edited March 27, 2012 by dave_59

[mea1201]

I ain't an expert, but here's how you can spawn multiple threads from within a class:

class whatever;
  // -- Stuff omitted for brevity of example.
  task sometask;
    foreach(e[i]) begin  // Can be a standard for loop as well.
      fork
        automatic int j = i;  // Put this in the fork declarative region to ensure each thread gets iteration value.
        forever begin
          e[j].wait_on();
          seq[j].start(agents[j].sequencer);
          e[j].reset();
        end
      join_none
    end
  endtask : sometask
endclass : whatever

Hi experts,

I want to write several forever blocks dynamically.

Just like:

fork
   forever begin
       e[0].wait_on();
       seq[0].start(agents[0].sequencer);
       e[0].reset();
   end

   forever begin
       e[1].wait_on();
       seq[1].start(agents[1].sequencer);
       e[1].reset();
   end

   ...
join

Then I want to use generate block to replace mass codes above and make it configurable.

for(genvar i=0 ;i< NUM; i++)
  forever begin
       e[i].wait_on();
       seq[i].start(agents[i].sequencer);
       e[i].reset();
  end

But compile error:

Verilog keyword 'genvar' is not expected to be used in this context.

How can i use generate block in a class context??

Thanks

[IChip]

Thanks, Dave & mea1201.

It works for me.

for(int n = 0; n<CLIENT_LEVEL_NUM; n++)
        fork
            automatic int j = n;
            forever begin
            ......
            end
        join_none

I have another workaround and maybe non-standard.

class A extends uvm_component;
 int i;

task run_phase(uvm_phase phase);
       forever begin
           e[i].wait_on();
           seq.start(agents[i].sequencer);
           e[i].reset();
       end
endtask
endclass : a

A x_agents = new[NUM];

[aji.cvc]

Few quick notes:

1. I believe generate is NOT allowed inside a class as generate is elab time and class objects are run-time

2. IChip - your work-around code doesn't seem to be fully shown (how is value of "i" fixed/assigned?). Note that it is important to have automatic variable inside the for loop inorder to get it correctly working - else all threads may use the last iteration value (or the one beyond, dpeending on your looping).

Regards

Ajeetha, CVC

www.cvcblr.com/blog

[IChip]

Thanks aji.cvc for your useful notes.

And I should add the line below in my workaround.

foreach(x_agents) x_agents.set_i(xxx);