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'Setting Forth' with Forth on the RC2014

T

his adventure started a few weeks ago when Spencer included an item in his RC2014 newsletter about James Bowman's port of CamelForth for RC2014.

I was intrigued by the arithmetic using double-length numbers and as James gives a few bits of example code in his article, it looked like a good opportunity to have a little foray into Forth. (I love the Jupiter Ace. I wish more had been sold so that they're a little less pricey today.)

I found several versions for CP/M. (I like using Compact Flash storage and CP/M on my RC2014.) Like BASIC, generic Forth sometimes doesn't work on the version you have without modification. Some versions contain more words or stick to the standard more closely than others. I tried Forth80, DXForth and UniForth as well as CamelForth and the one I like best is DXForth (I'm not recommending it over the others, it just worked best for me as I worked through some examples. I'd encourage anyone to try all of these and make up their own mind.)

The last thing I needed in my life was a new language. I use an object-orientated version of C in my day job, and assembly language with retro-computers. You can't beat the speed and efficiency of assembly. I wouldn't have considered using a higher-level language* for 8-bit computing.  Yet there was something about Forth that really appealed. 

It produces a compiled executable, which is pretty efficient and runs at close to assembly speeds. You can even write blocks of assembly in your Forth. Developing is very neat and efficient and it's easy to do it directly on the RC2014. If you buy into the way that Forth works, it forces you to think and program in a different way. 

I could write pages about this. But this is where the dice program comes in. Once I'd learned how to store and read bitmap data in Forth (hint: 'unindexed array'), send data to my OLED screen and read the buttons on my digital i/o module, building those things into a program was very quick and simple. 

Useful 'getting started' links:

Ed has provided me with this Google drive link which contains latest versions of DXForth

Archived copy of Ed's DXForth page 

Learn X in Y minutes where X = Forth (a beautifully straightforward 'getting started' page)

Thinking Forth by Leo Brodie - download and find Appendix A for more inroads. The rest of the book is a great read.


* it's arguably not a higher-level language, see "But Is It a High-Level Language?" page 27 of Leo Brodies' book.

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  1. Cuvtixo2 January 2021 at 15:49

    I'm really surprised you didn't mention Tynemouth's 4th Minstrel - Jupiter Ace replica. I got a kit from thefuturewas8bit.com but haven't had time to put it together. It's RC2014 bus compatible! I first heard of FORTH when I had a PowerPC iBook, and I briefly toyed with the idea of learning for that reason. The boot firmware for PowerPC Macs was written in that language when PCs just had humble BIOS and UEFI wasn't yet invented. It has a long history in the embedded world, and is ideal for that purpose, although I never got around to actually learning any, hopefully I'll learn when my Minstrel4 gets put together!

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  2. peahen2 January 2021 at 16:42

    I'm quite envious. My first Tynemouth kit was the Mini Pet and I was really impressed with the kit & documentation. I have always loved the look of the Ace, it's such a shame that original ones are silly money now. Since starting to learn about Forth I've been even more interested in that computer, and when I finally made the decision to grab a Minstrel Fourth kit from tfw8bit, they'd all gone. It's important with this 'new old stuff' to buy it when you see it, stuff tends to be produced in batches. I didn't know that fact about Macs. I've been a Mac person for a long time and have a number of powerPC macs and an iBook. One more reason to love them! Enjoy building and using your kit.

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