Uvm_sequence without #(seq item)

UVM
,
1

Can I define a class with uvm_sequence without writing uvm_sequence#(seq_item) and will it work and if it works what are the conditions for it?

class xyz extends uvm_sequence
`uvm_object_utils(xyz)
…

2

In reply to vineetkumar99:
If you do not pass a sequence item to your sequence definition this sequence is considered as a virtual sequence. A virtual sequence is not generating any seq_items.

3

In general if you are using a parameterized class, and you forget (or dont intend to) add a parameter then the default parameter value is
used.

In this case uvm_sequence is a parameterized class that uses two parameters

virtual class uvm_sequence #(
   	type 	REQ	 = 	uvm_sequence_item,
   	type 	RSP	 = 	REQ
) extends uvm_sequence_base

The default parameter value for REQ is uvm_sequence_item
and the default parameter value for RSP is REQ which in this case resolves to uvm_sequence_item

So the following are equivalent:

  1. uvm_sequence // Note no parameters
  2. uvm_sequence #(uvm_sequence_item) // Note the RSP takes the same value as REQ
  3. uvm_sequence #(uvm_sequence_item, uvm_sequence_item) // Values are given for both parameters.

Hope this helps.

Logie Ramachandran
Verikwest Systems Inc