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
        // alu_op <= 0;
        case (opcode)
            // Write solution here
            2'b00 : alu_op <= 1;
            2'b01 : alu_op <= 2;
            2'b10 : alu_op <= 4;
            2'b11 : alu_op <= 8;
            default : alu_op <= 2'b00;
        endcase
    end
endmodule