This is a fully-functioning Forth interpreter faithfully ported from the original by Richard W.M. Jones:

https://rwmj.wordpress.com/2010/08/07/jonesforth-git-repository/

You can see the full original source in the jonesforth/ directory in this repo.

This repo is a port from the original GNU Assembler (GAS) implementation to the Netwide Assembler (NASM). The biggest difference between the two assemblers is AT&T-style GAS syntax vs. Intel-style NASM syntax. But I have made a couple changes. The biggest one is that nasmjf loads the jonesforth.f source file (containing the second half of the interpreter written in Forth) upon startup.

See "Loads Jones’s FORTH source on start" below.

The assembly portion of this interpreter port is pretty much "done". I’m currently testing the rest of the built-in words and then I’ll shift to cleaning up and improving the comments and structure of the assembly source.

Check out the log text files. They’re my rambling learning-in-public and thinking "out loud" way of describing what I’m up to. The latest log will probably give an idea of what I’m currently doing or what I’ve most recently completed.

I also wrote an article about my delightful process with this project: http://ratfactor.com/assembly-nights

I also have a placeholder for future notes and rambling thoughts about the project here: http://ratfactor.com/nasmjf

The implementation of JONESFORTH is in two parts: an assembly language "bootstrap" and additional essential word definitions written in FORTH.

This NASM contains a hard-coded path to the jonesforth.f FORTH source file and reads it automatically when the interpreter starts. This is to make starting and debugging the system easier and more convenient.

If you wish to disable or simply examine this change, search for lines with comments containing the string LOADJF. You can comment out most of these lines. A few will need to remain. Figuring out which is "left as an exercise for the reader", as they say.

Assemble and link with:

Run by calling the executable you just compiled:

I’ve made heavy use of the GNU Debugger to fix mistakes, understand what my program is doing, and in these early stages, it’s nearly the only way to tell what’s happening in the program at all.

I’m assembling with DWARF2 debugging info. See the r script for params.

See gdb.script for current defaults I’m using.

Show stuff:

Print values (register, label, literal numbers (handy as base converter)

Print value at memory location

Set temporary break and jump to location (by label)

Create GDB commands

See the file screenrc in this repo to see the current convenience setup. In short, I’ve got a GDB session and Vim session open in separate windows so I can quickly toggle between them. Anything outside of those two applications is best done in a new window to keep from accidentally closing one of the two main windows.

• C-j C-j toggle between main windows

• C-j c create a new window with a shell

• C-j H start (or stop) logging window (not actually what I want)

• C-j h save hardcopy of scrollback buffer (actually what I want)

• C-j ? help (show other shortcuts)

I’m using the hardcopy feature to help me record running each milestone of progress in GDB sessions to test and document (and celebrate!) the work.

An alias called rc starts my two-windowe session like so:

My whole setup on this machine is dedicated to this project. Here’s the entirety of my current .vimrc:

Because Richard Jones released his work as public domain, it’s only right that I should release my port also as public domain. So here’s the license:

I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.

In case this is not legally possible, I grant any entity the right to use this work for any purpose, without any conditions, unless such conditions are required by law.