Write method as task

UVM
1

Hi All,

Can the write method of analysis port which used to communicate between monitor and scorebaord be declared as task instead of function? If no, why so?

Regrads,
Abhinandan

2

It can be declared as a task provided there are no blocking statements ( although from a strict LRM perspective it’s illlegal to call a task from a function w/o fork join_none )

The reason it’s a function and not a task is due to it’s definition in class uvm_tlm_if_base

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3

The base class prototypes write() as a function. Per the LRM, you are required to follow the same prototype, so write() needs to be declared as a function. You will get an error if you declare it as a task.

4

On replacing component_b :: write in edalink as

 virtual task write(transaction trans);  
    `uvm_info(get_type_name(),$sformatf("Inside NEW write method.Received trans On Analysis Imp Port "),UVM_LOW)
    `uvm_info(get_type_name(),$sformatf(" Printing trans, \n %s",trans.sprint()),UVM_LOW)
  endtask

The code does work on 2 EDA tools ( VCS & Questa ).

Pls note that I understand that ideally one shouldn’t declare write as a task and that LRM terms it illegal

Coincidentally a few yrs ago I had a colleague who had declared his write as a task and the simulation did go through ( along with Warning msg).

When I asked him to add #0 within task write and re-run the tool had given a compilation error.

1 Like
5

As mentioned by @AGS91 if we declare task it still works and no compilation error is thrown. One of my colleague declared it as task, and it is working.

Regards,

Abhinandan

6

Thanks for the reply.

Regards,
Abhinandan

7

The uvm_analysis_imp class has an internal write() method which is declared as a function. It will in turn call the write function/task of the class which is instantiating it. I was incorrect when I stated you will get an error, as you aren’t redefining the write() method.

3 of the simulators will give you a warning about calling a task from a function. The fourth will generate an error.