Using Systemverilog static variable in class

Question

I'm stuck in a problem and would appreciate any input/suggestion:

I've an agent for my test bench which has following components: a base class A- it defines two static variables- X and Y two new classes B and C, BOTH extended from A. They both use the static variable declared in base class. Another class D which utilizes B and C to do something.

Lets say class D is my top agent and I call it bfm_agent. This bfm_agent can be instantiated multiple times in my test bench. Now the problem is, X and Y will be shared to all bfm_agent. I don't want that. I just want X and Y to be static so that class B and C inside each bfm_agent can use these two variables to do some work.

How can I achieve this? I just want the scope of these two static variable to be valid only within each instance of bfm_agent.

dave_59 · Accepted Answer · 2014-12-05 05:33:51Z

2

You should use a configuration object that contains the variables X and Y. Then have the base class A construct the config object if it does not exist and then do set it for each instance of the agent.

class A extends uvm_component;

my_config_c myconfig;

function void build_phase(uvm_phase phase);
...
  if(!uvm_config_db#(myconfig)::get(get_parent(),"","myconfig",myconfig)) begin
     myconfig = my_config_c::type_id::create("myconfig");
     uvm_config_db#(myconfig)::set(get_parent(),"","myconfig",myconfig)
  end
endfunction

Now both classes B and C will be able to refer to myconfig.X and myconfig.Y.

answered Dec 5, 2014 at 5:33

dave_59

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2 Comments

Tudor Timi Over a year ago

@newbie static means across all instances. What you want are instance variables. If you declared your X and Y variables as static in order to do this kind of sharing I would say you remove the static keyword and assign the correct values for each instance. Dave's approach works best if you're using UVM.

dave_59 Over a year ago

Since the post was tagged with UVM I assumed they were already using it. If notm you could still do something similar by sharing handles, not the variables themselves.

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