I had the good luck to take Doug Comer's final XINU class. One of the highlights of my time in college. It was a simple, non memory protected system that implemented some basic OS concepts without overly being complex.

One thing I'll suggest about your task switching code is that you don't have to ...

Thanks for the reminder about PostScript. One of those languages I need to visit someday. I actually got to meet John Warnock once, about a million years ago. Still have his business card in a box.

Turtle Graphics has a pretty long history with FORTH, not just LOGO or Pascal. So I decided to write a Turtle Graphics module in PLASMA and interact with it in PLEIADES FORTH. Honestly, FORTH seems like a better match to Turtle Graphics than LOGO, which I never really got.

This was my first time ...

PLasma Enhanced InterActive Development EnvironmentS

After a long gestation period, PLASMA has been reborn as PLEIADES with many new features, enhancements and bug fixes.

TLDR; Check out the video: https://youtu.be/nrCwYxA_N_E

From the GitHub project page: https://github.com/dschmenk/PLASMA ...

To follow up with Bruce's NEXT in ZP and the importance of a quick DROP, I actually put DROP right in front of NEXT in ZP. Since I use a split stack, this consists of 'INX'.

I can see why the middle character is better for the hash than the 2nd one or the last one ... because a number of words in the dictionary will end in ] ! @ + and similar abbreviations, and some words will have a common start, like UM* and UM/MOD and UM/.

But what is especially clever is that you ...

Are you going to pre allocate the dictionary? How big will it be?

I do believe having a hash table is quite useful for improving lookup speeds.

I was looking at LISP implementations for the 6502 when I was writing my LISP for PLASMA when I came across a modern-ish one that tried to use a hash to ...

Here is my Apple 1 FigForth implementation that uses the CFFA1. I keyed in the PolyForth editor and assembler according to my blog post: http://schmenk.is-a-geek.com/Forth.html

I worked around using the CFFA1 as a block device through a ProDOS formatted partition by simply naming each block as a ...

Many moons ago I wrote an Apple II emulator for the PalmPilot PDA. Original site: https://palmapple.sourceforge.net/ , archived site with source: https://github.com/dschmenk/Appalm/tree/master. Basically a 68000 with an 8 bit data bus. At 16 MHz. So many concessions had to be made to get anywhere ...

Hurrah! Can't wait to see what the hybrid VM will do
Not sure what you mean... The last result is the "Native" (6502 assembler + Plasma code) VM. No C code at all.
When the C coded VM gets compiled for ARM and the byte codes get interpreted from the ARM core as an accelerator. Now you're cooking ...

Hurrah! Can't wait to see what the hybrid VM will do

It would be good, I think, to allow for enabling tracing from run6502, perhaps with a -t flag. I've done something like that locally. (I think I've also sometimes put in some kind of cycle count delay interface, so I can start tracing the code I care about, not the entire reset sequence.)

I think ...

Hi Ed-
Yes, although my changes weren't as extensive and I didn't really check any of the flags other than carry:

https://github.com/dschmenk/PLASMA/commit/d767418eff959af07566bec5ed2a2c781848ebe3

BTW, I was able to track this down by enabling the single step/trace feature I added to lib6502 and ...

I just want you to get back to PLASMA

Try reordering your .o and library files in the command line. Put the the .o files you compiled first, then the pre-built .o and library files last. You want the references to search from left to right. Something like:


ld65 -v --allow-multiple-definition --target rp6502 -m greg.map greg.o ria.o ...