`timescale 1ns/1ns module mux4_1( input [1:0]d1,d2,d3,d0, input [1:0]sel, output[1:0]mux_out ); //*************code***********// reg[1:0]mux_out_reg; always@(*)(1444584) begin case(sel) 2'b00:begin mux_out_reg = d3; end 2'b01:begin mux_out_reg = ...