- Author: Richard James Howe
- E-mail: mailto:howe.r.j.89@gmail.com
- License: The Unlicense / Public Domain
- Repo: https://github.com/howerj/ascii
- Project: A VM with an ASCII based instruction set
This (silly) project is a work in progress. The idea is to make a Virtual Machine (VM) that only uses printable ASCII characters as instructions, just for fun. It might be possible depending on the choice of instructions to make a VM could in principle be implemented in hardware on an FPGA. I do not think it is a particularly viable concept however, and you would be best placed with a more traditional architecture (and programming language).
One concept (that can be disable at compile time) is to store everything in memory as ASCII characters as well. For example a 16-bit value would not take up 2 bytes but instead 4 bytes (so the entire memory is readable as text).
The VM implements a 16-bit (although in principle it should be easy enough to change this) dual-stack stack machine.
Ideally we would make some test programs (such as a monitor, program loader, Forth interpreter, hexdump utility, etcetera) for the CPU to tests its functionality.
Jump locations can be stored on the return stack by the VM, however forward references have to be manually dealt with (and as all programs are in ASCII all characters need to be accounted for).
As mentioned, this is not a serious project, there are much better languages out there that could be implemented in roughly the same amount of code (e.g. Lisp, Forth, an APL like language, prolog, TCL to name a few) with many examples being scattered across the internet.