Copyright 2015-2024 Caleb Evans
Released under the MIT license

This program simulates a processor cache for the MIPS instruction set architecture. It can simulate all three fundamental caching schemes: direct-mapped, n-way set associative, and fully associative.

The program must be run from the command line and requires Python 3.4+ to run. Executing the program will run the simulation and print an ASCII table containing the details for each supplied word address, as well as the final contents of the cache.

For example, the following command simulates a 3-way set associative LRU cache, with 2 words per block. To see all examples and their respective outputs, see examples.txt.

# 3-way set associative (LRU; 2 words per block) cache-simulator --cache-size 24 --num-blocks-per-set 3 --num-words-per-block 2 --word-addrs 3 180 43 2 191 88 190 14 181 44 186 253

This produces the following output:

 WordAddr BinAddr Tag Index Offset Hit/Miss -------------------------------------------------------------------------------- 3 0000 0011 00000 01 1 miss 180 1011 0100 10110 10 0 miss 43 0010 1011 00101 01 1 miss 2 0000 0010 00000 01 0 HIT 191 1011 1111 10111 11 1 miss 88 0101 1000 01011 00 0 miss 190 1011 1110 10111 11 0 HIT 14 0000 1110 00001 11 0 miss 181 1011 0101 10110 10 1 HIT 44 0010 1100 00101 10 0 miss 186 1011 1010 10111 01 0 miss 253 1111 1101 11111 10 1 miss Cache -------------------------------------------------------------------------------- 00 01 10 11 -------------------------------------------------------------------------------- 88,89 2,3 42,43 186,187 180,181 44,45 252,253 190,191 14,15 

You can install Cache Simulator via pip, or using your preferred package manager (like uv):

# via pip pip3 install cache-simulator

# via uv uv tool install cache-simulator

The size of the cache in words (recall that one word is four bytes in MIPS).

One or more word addresses (separated by spaces), where each word address is a base-10 positive integer.

The program internally represents all cache schemes using a set associative cache. A value of 1 for this parameter (the default) implies a direct-mapped cache. A value other than 1 implies either a set associative or fully associative cache.

The number of words to store for each block in the cache; the default value is 1.

The number of bits used to represent each given word address; this value is reflected in the BinAddr column in the reference table. If omitted, the default value is the number of bits needed to represent the largest of the given word addresses.

The replacement policy to use for the cache. Accepted values are lru (Least Recently Used; the default) and mru (Most Recently Used).