Override by sequence type changes handle type everywhere whereever it is declared in driver even if it is parameterized or how?

UVM
1

I have one sequence item which is overriden by another sequence item.
now I have overwrite first sequence item with the second sequence item using type override.now I have the driver code as follows. driver code is declared using first sequence item.snippet is as follows. in following code there are 3 places .which place exactly this type overwriting happens.Could you please clarify

class uvm_driver_e  extends uvm_driver #(first_seq_item);// first place
 
first_seq_item handle; //second place

task run_phase(uvm_phase phase);

............
seq_item_port.get_next_item(handle);  //third place

.............................
2

uvm_driver is defined as

class uvm_driver #(type REQ=uvm_sequence_item,
                   type RSP=REQ) extends uvm_component;

  uvm_seq_item_pull_port #(REQ, RSP) seq_item_port;
  REQ req;
  RSP rsp;
...

There is no need to declare a separate handle, just use req. That removes the second place declaration.

The UVM factory override only affects the construction of an object instance; it does not override the class variable where its handle is stored.

1 Like
3

Hi Dave,

Thanks for the clarifications. Could you please provide the below clarifications too. then only whenever the base sequence item object is constructed instead of creating base class sequence item object , it creates the derives class item object and assigns to the base class item handle . then if I need to call the derived class item class variables in driver , please clarify do I need to modify the driver with $cast or how it needs to reference the derived class variables in driver.