`timescale 1ns/1ns module main_mod( input clk, input rst_n, input [7:0]a, input [7:0]b, input [7:0]c, output wire [7:0]d ); wire [7:0] c1; wire [7:0] c2; mod mod_inst1 ( .clk(clk), .rst_n(rst_n), .a(a), .b(b), .c(c1) ); mod mod_inst2 ( .clk(clk), .rst_n(rst_n), .a(a), .b(c), .c(c2) ); mod mod_inst3 ...