71. Arithmetic Logic Unit

How do you plan to solve it?

/*Write your code here*/
module alu4(input [3:0]a,b, input [2:0]op,output reg[3:0]y,output reg cf);
always @* begin
    cf=0;
    case(op)
        3'b000:{cf,y}=a+b;
        3'b001:begin y=a-b;cf=(a<b);end
        3'b010: y=a&b;
        3'b011: y=a|b;
        3'b100: y=a^b;
        default:y=0;
    endcase
end
endmodule