设计与验证verilog hdl

				module top (clk_cpu, rst, CS_, OE_, WR_, Addr, data_bus);
				
				input       clk_cpu, rst;
				input        CS_, OE_, WR_;
				input [7:0] Addr;
				inout [7:0] data_bus;
				
				wire [7:0] data_in;
				wire [7:0] data_out;
				wire       my_wr, my_rd;
				wire       CS_reg1, CS_reg2, CS_reg3; // the register selection
				wire [7:0] reg1, reg2, reg3;          // the register to be read and written
				
				assign data_in = data_bus;
				
				decode decode_u1  (.CS_(CS_), 
				                   .OE_(OE_), 
				                   .WR_(WR_), 
				                   .Addr(Addr), 
				                   .my_wr(my_wr), 
				                   .my_rd(my_rd), 
				                   .CS_reg1(CS_reg1), 
				                   .CS_reg2(CS_reg2), 
				                   .CS_reg3(CS_reg3)
				                   );
				
				write_reg write_reg_u1 ( .clk(clk_cpu), 
				                         .rst(rst),
				                         .data_in(data_in),  
				                         .my_wr(my_wr), 
				                         .CS_reg1(CS_reg1), 
				                         .CS_reg2(CS_reg2), 
				                         .CS_reg3(CS_reg3), 
				                         .reg1(reg1), 
				                         .reg2(reg2), 
				                         .reg3(reg3)
				                         );
				
				read_reg read_reg_u1  ( .clk(clk_cpu), 
				                         .rst(rst),
				                         .data_out(data_out),  
				                         .my_rd(my_rd), 
				                         .CS_reg1(CS_reg1), 
				                         .CS_reg2(CS_reg2), 
				                         .CS_reg3(CS_reg3), 
				                         .reg1(reg1), 
				                         .reg2(reg2), 
				                         .reg3(reg3)
				                         );
				
				
				                   
				assign data_bus = ((!CS_) && (!OE_))? data_out : 8'bZZZZZZZZ;                    
				                    
				                    
				                    
				endmodule