interface intf (
    input logic clk
);
  import typedef_pkg::*;

  logic op_start = 1'b0;
  operation_t operation = ADD;
  operand_t operand_a = '0;
  operand_t operand_b = '0;
  result_t result;

  clocking cb @(posedge clk);
    output op_start;
    output operation;
    output operand_a;
    output operand_b;
    input result;
  endclocking
endinterface : intf