This document provides a testbench for a memory simulator. It initializes a memory array, loads and prints the initial memory contents. It then performs some store operations and prints the updated memory contents. Finally, it copies the final memory contents to an external file. The testbench initializes a memory array from an input file, loads and stores values to simulate memory behavior, and outputs the final memory image to a file.

1. --------------------------------------------------------------------------<br />-- Download and save file as mem_tb.vhd<br />-- AUB<br />-- EECE 321 - Computer Organization, Spring 2009<br />-- Author: M. M.<br />--------------------------------------------------------------------------<br />-- Description: Testbench for memory simulator<br />--------------------------------------------------------------------------<br />library ieee;<br />use ieee.std_logic_1164.all;<br />use ieee.std_logic_unsigned.all;<br />use ieee.std_logic_arith.all;<br />use ieee.std_logic_misc.all;<br />USE ieee.std_logic_textio.all;<br />USE std.textio.all;<br />LIBRARYwork;<br />USE work.auxiliary.all;<br />-- Dummy entity<br />ENTITY mem_tb is<br />END mem_tb;<br />-- Memory simulator architecture<br />ARCHITECTURE mem_tb of mem_tb is <br />-- input and output file name<br />CONSTANT in_fname : STRING := quot;
..oem_input_file.txtquot;
;<br />CONSTANT out_fname : STRING := quot;
..oem_image_file.txtquot;
;<br />BEGIN<br />mem_behavior: process is<br />VARIABLE mem : MEM_ARRAY(0 to 63);<br />VARIABLE word : MIPS_WORD;<br />VARIABLE data : INTEGER;<br />BEGIN<br />-- initialize memory<br />init_mem(in_fname, mem);<br />-- load memory contents and print them<br />for i in mem'range loop<br />word := load_word(mem,4*i); -- note byte address<br />report quot;
word at byte address quot;
& integer'image(i) & quot;
= quot;
& integer'image(conv_integer(word));<br />end loop;<br />-- perform some store operations<br />data := 16#22#;<br />word := conv_std_logic_vector(data,word'length); -- convert data into a 32-bit vector<br />store_word(mem,word,16#4#);<br />data := 16#33#;<br />word := conv_std_logic_vector(data,word'length); -- convert data into a 32-bit vector<br />store_word(mem,word,16#C#);<br />data := 16#44#;<br />word := conv_std_logic_vector(data,word'length); -- convert data into a 32-bit vector<br />store_word(mem,word,16#14#);<br />-- print new memory contents onto console<br />for i in mem'range loop<br />word := load_word(mem,4*i); -- note byte address<br />report quot;
word at byte address quot;
& integer'image(i) & quot;
= quot;
& integer'image(conv_integer(word));<br />end loop;<br />-- copy contents of memory into an external file<br />copy_mem_2_file(out_fname, mem);<br />-- perform other memory functions<br />wait;<br />END process mem_behavior;<br />END mem_tb;<br />