write code in hdl for four moduls

A. Design a combinational circuit that generates the 9's complement of a BCD digit. Develop and simulate a data flow model (don't use the behavioral model for this component) of a circuit that generates the 9's complement B. Design a combinational circuit that describes the quadruple 2x1 multiplexer using a behavioral model. Develop and simulate a behavioral model (don't use the data flow model for this component). C. Design a combinational circuit for BCD adder. See Figure 4.14 of the textbook for the whole design of the BCD adder. Develop and simulate a data flow model (don't use the behavioral model for this component) for the BCD adder. D. Integrate the whole components of the system by developing and simulating a structural model of Figure 1. In your design, make sure that (1) the BCD adder should be described as a data flow model in a separate module, (2) the 9's complementor should be described as data flow model in a separate module, and (3) the quadruple 2X1 multiplexer be described as a behavioral model in a separate module. Finally, all the system components are to be instantiated in a top-level module using a structural model