`timescale 1ns/1ns module rom( input clk, input rst_n, input [7:0]addr, output [3:0]data ); reg [3:0] rom [0:7]; integer i; always@(posedge clk or negedge rst_n) if(!rst_n) begin for(i=0;i<8;i=i+1) rom[i] <= i << 1; end assign data = rom[addr]; endmodule