Binary to BCD converter (4-bit)

Hi, i want to design a 4-bit BintoBCD converter Using Xilinx and need to do it structurally. I know the behavioral way in Verilog(Basically it's the if-else statement). Just want to how to graph it using the 2X1 mux , comparator , adder and substracter.

input [3:0] cnt;
output[3:0]tens,ones;

Thanks