Introduction

Version: 0.1pre

LogiSpim is a 32-bit MIPS processor built in Logisim-Evolution with associated tooling for running single-file MIPS programs on the processor. This has been created as a tool to help in learning pipelining in MIPS processors, and to offer a more in-depth experience in an introduction to micro-architecture. The ISA implementation was inspired by this MIPS data sheet.

Features

• Assistive program for compiling and viewing MIPS instructions programs.
• Detailed documentation of micro-architecture for improved learning and understanding.
• Pipeline status view to easily display which instructions are in which parts of the pipeline at any given moment.
• Support for emulated console output through syscalls.
• Built-in breakpoint feature for debugging.

⚠️ Important Notice

This website and project is currently under construction. Progress is being made, and will eventually be released, once a satisfactory amount of work has been done. Expected Release around late April 2026.

Supported Instructions

The instruction set implemented in this processor was based on this MIPS reference sheet.

Note: This CPU currently does NOT support floating point operations.

* The syscall instruction has a move $k0, $ra instruction inserted prior to it by the pre-processor. This is done to allow for syscall to preserve the value in $ra, since syscall acts similarly to a jal instruction; despite the convention placing the responsibility of preserving the content of $ra on the callee. Future improvements may remove the need for this additional instruction's insertion.