A modport expression allows elements of arrays and structures, concatenations of elements, and assignment pattern expressions of elements declared in an interface to be included in a modport list. This modport expression is explicitly named with a port identifier, visible only through the modport connection.

One of the best way to use this feature is to use with genvar on modports to make parameterizable interface. Below examples shows exactly same.

  1 // TODO : Complete this example
  2 //+++++++++++++++++++++++++++++++++++++++++++++++++
  3 // Define the interface
  4 //+++++++++++++++++++++++++++++++++++++++++++++++++
  5 interface arb_if #(num_agents = 1) (input clk);
  6   logic   reset;
  7   logic  [num_agents-1 : 0] req;
  8   logic  [num_agents-1 : 0] gnt;
  9   //=================================================
 10   // Modport inside a generate block
 11   //=================================================
 12   for (genvar i=0; i< num_agents; i++) begin: arb
 13      modport arb (input .creq (req[i], clk, reset, output .cgnt (gnt[i]) );
 14      modport tb (output .creq (req[i], input clk, reset, .cgnt (gnt[i]) );
 15   end
 16 
 17 endinterface
 18 
 19 //+++++++++++++++++++++++++++++++++++++++++++++++++
 20 //  Testbench Top file 
 21 //+++++++++++++++++++++++++++++++++++++++++++++++++
 22 module interface_modport_expression();
 23  
 24  logic clk = 0;
 25  always  #1  clk ++;
 26  
 27  arb_if arbif(clk);
 28 
 29 initial begin
 30   #100  $finish;
 31 end
 32 
 33 endmodule

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