`timescale 1ns/1ns module main_mod( input clk, input rst_n, input [7:0]a, input [7:0]b, input [7:0]c, output [7:0]d ); wire [7:0]d_r1,d_r2; mod U1(.clk(clk),.rst_n(rst_n),.a(a),.b(b),.d(d_r1)); mod U2(.clk(clk),.rst_n(rst_n),.a(a),.b(c),.d(d_r2)); mod U3(.clk(clk),.rst_n(rst_n),.a(d_r1),.b(d...