51. Opcode Decoder

How do you plan to solve it?

module alu_decoder (
    input  [1:0] opcode,
    output reg [3:0] alu_op
);
    always @* begin
        case (opcode)
            // Write solution here
                2'd0:alu_op=1;
                2'd1:alu_op=2;
                2'd2:alu_op=4;
                2'd3:alu_op=8;
        endcase
    end
endmodule