def-not-ys/baby_vm

a baby vm with only one instruction

baby_vm

baby_vm is a virtual machine (VM) that implements one-instruction set computer (OISC).

baby_vm is still under construction. The to-dos are listed below:

TO-DO

Features

Execution

• Add return value address
• add capability to display return value

Add compiler in racket

• define bnf of the input language
  • refer to simple math-lan in 311
• design intermediate languages
• design compiler

General

• add Dockerfile and complete the How to run section
• abstraction for memory address - added decode layer to turn relative index to memory data region address
• add support for flags
• implement stack memory support
• implement heap memory support
• implement syscall assmebly support
• keep updating the documentation

Testing

• supply simple assembly program file for testing
• Add test suite to test machine functionality
• convert simple c program to one-line instruction assembly code
  • maybe simple additions
• test converted assembly code
• [?] add testing input example to print "hello world" - ? this requires IO capacity?

General information

Inspired by this tutorial for writing your own vm, I got the idea of writing a simple baby vm that only runs one instruction and see how far I can get.

The one instruction that runs on baby_vm is SUBLEQ

    Instruction subleq a, b, c
        Mem[b] = Mem[b] - Mem[a]
        if (Mem[b] ≤ 0)
            goto c

A simple ISA around SUBLEQ was also deigned for baby_vm to interpret the assmebly files.

baby_vm has its own memory and hardware models.

All design deatils are documented in /doc/DOCUMENTATION.md.

This project is for fun and educational purpose, not meant to be useful. :)

How to run

By the time this is publish, I should have dockerize baby_vm. So the following steps should get baby_vm up and running:

1. make sure docker is installed.

• docker --version will show if docker is installed.

2. from the project directory, build docker

• cd baby_vm/
• docker build --no-cache -t baby_vm .

3. run docker

• docker run -it --tty baby_vm:latest

4. baby_vm will propmt you to enter the assmebly files that you want to run, there are some example files supplied in baby_vm/examples/, enter the file name with path relative to the project directory. for example:

• examples/test.txt
• if you want to run your own assembly file (please refer to doc/DOCUMENTATION.md for ISA), make sure enter the file name with the path relative to the project directory.

5. watch baby_vm run :)

Anything else?

contributions welcome :)