module duv (
input logic clk,
input logic op_start,
input logic  [1:0] operation,
input  logic [7:0] operand_a,
input  logic [7:0] operand_b,
output logic [15:0] result
);

logic [15:0] result_tmp;

always_ff @(posedge clk) 
begin
if( op_start == 1'b1)
begin
case (operation)
      0:             result_tmp = operand_a + operand_b;
      1:             result_tmp = operand_a * operand_b;
      2:             result_tmp = operand_a | operand_b;
      3:             result_tmp = operand_a & operand_b;
    endcase
  end

	result <= result_tmp;
end

endmodule : duv