Array of parameterized interface

SystemVerilog
,
1

Hi everybody,

I have to use an array of parametrized interface for my project but something is strange. The definition of the interface is:


  interface itf_test #(
    type PAYLOAD_TYPE = logic [31:0] // Default type
  ) (
    input logic clk,
    input logic reset
  );

  // ----------------------------------
  // Signals
  // ----------------------------------
  PAYLOAD_TYPE payload;
  logic vld;

  endinterface: itf_test

In my testbench, when I instantiate my array:


  parameter int N_TB = 4;

  itf_test #(
    .PAYLOAD_TYPE  (PAYLOAD_ITF_TEST_T)
  ) itf_test [N_TB:1] (
    .clk           (clk),
    .reset         (reset)
  );

where {PAYLOAD_ITF_TEST_T} is:


  typedef struct packed {
    logic [31:0] data;
    logic [31:0] time_tag;
  } PAYLOAD_ITF_TEST_T;

I have the following info from Questa 10.6b:
**

UVM_INFO @ 0: reporter [itf_test_tb] Size of PAYLOAD_ITF_TEST_T = 64

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test[1].payload = 32

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test[2].payload = 32

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test[3].payload = 32

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test[4].payload = 32

**

It seems like the parameter passed to the array is completly ignored. Instead, it is the default parameter which is used.

But, when I instantiate four {itf_test} interfaces (the ugliest way), I have the following info:
**

UVM_INFO @ 0: reporter [itf_test_tb] Size of PAYLOAD_ITF_TEST_T = 64

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test_1.payload = 64

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test_2.payload = 64

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test_3.payload = 64

UVM_INFO @ 0: reporter [itf_test_tb] Size of itf_test_4.payload = 64

**

This is, honestly, above my understanding. If someone knows what happens, I’ll be very grateful. Thanks for your time.

Louis-Alexandre

2

In reply to lal-elsys:

I’m not able to reproduce your problem. Can you code up a minimal complete example, like this:

interface itf_test #(
		     type PAYLOAD_TYPE = logic [31:0] // Default type
		     ) (  );
   
   PAYLOAD_TYPE payload;
   
   initial $display("%m payload size %d",$bits(payload));
   
endinterface: itf_test

module top;
   parameter int N_TB = 4;
   typedef struct packed {
      logic [31:0] data;
      logic [31:0] time_tag;
   } PAYLOAD_ITF_TEST_T;
   itf_test #(
	      .PAYLOAD_TYPE  (PAYLOAD_ITF_TEST_T)
	      ) itf_test [N_TB:1] (
				   );
endmodule

# top.itf_test[4] payload size          64
# top.itf_test[3] payload size          64
# top.itf_test[2] payload size          64
# top.itf_test[1] payload size          64