I'm curious. How many here are doing all their coding on the machine they built? Using tools they created?

I have a couple of versions of some of my builds that I program in BASIC. Usually to test ideas quickly. But while the BASIC is resident and I have done some tweaks, I can't claim to have built the base interpreter myself.

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Bill

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Back in the day I was definitely into that -- creating and using my own tools. Most notable are the tools used for a series of microcontroller jobs starting in 1980 or thereabouts.

Hard to imagine, but back then microcontrollers were almost unheard of -- just barely a thing. You can be sure I was excited when I realized I'd be able roll my own Development System for the Intel MCS48 family, the first or maybe second microcontroller ever! (A Development System from Intel would've been stupidly expensive, utterly out of reach.)

The MCS48 chips are 40-pin devices, usually with three 8-bit parallel ports, 1K of (EP)ROM and *zero* RAM... well, almost. I knew enough Forth to write an MCS48 assembler that accepted proper Intel assembly source, and in an Intel databook I found enough info to build my own blaster for the EPROM versions such as 8748 and 8741. One-chip computers!!!

The host system was my 128 KByte KIM-1, running FIG Forth. The attached mass storage was a Z80-based homebrew floppy disk system equipped for 5" at first, later upgraded for 1.44 MB 3". All of this was before I acquired my first DOS box.

-- Jeff

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

It's true. Nowadays I'm much more likely to edit and store the source code on an x86 box. When I'm ready I'll squirt it out to PRN, and KK (my KIM-1's successor) thinks it's a human typing at KK's keyboard.

But, back in the day, KIM-1 was the only computer I owned. It was used for everything, including creation of the code (using a homebrew editor and a TV adapted as a monitor) that eventually supported the MCS48. FWIW there are a few photos in this post.

Nowadays there's little coding activity for my beloved homebrew systems, self-hosted or otherwise. They're mostly just a leisure pursuit; a hobby...

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

Holy ceramic memory chips, Batman! That's one heck of a Kute Kim.



I'm utterly humbled by the brains on this site. There are so many great minds here I'd hate to try to make a list lest I leave someone deserving off. I mean that too.

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Bill

Not just x86 - you can just as easily use an ARM host nowadays, with a Raspberry Pi. In some ways, interfacing one to your SBC to transfer the build is also easier.

I started (and still use) ca65 (from the cc65 suite) for development on my Ruby 6502 and '816 systems. I also created a cc65 target for it, so can do ASM and C on a Linux host.

My ultimate aim is for Ruby'816 to be self-hosting. So it has a filing system, serial interface and it runs BBC Basic.

For a while I looked at C running natively (I did use Aztec C on an Apple II in the early 80's and another C on a CP/M system) but I remembered compiling being very slow back then - probably no better today. Quite limited too, so I've settled on BCPL. I did a lot of BCPL coding in the 80s on the 6502 based BBC Micro) So now I have a 32-bit BCPL system running on the '816. The low-level OS is an Acorn MOS look-a-like (BBC Micro operating system) which I wrote from scratch The BCPL Cintcode (the name of the bytecode the compiler generates) interpreter (32-bit bytecode VM thing) is all written in ASM with a C front-end which I'm slowly re-writing in a mixture of ASM and BCPL. The upper level "OS", program launcher, command-line interface, etc. is all in BCPL.

Todays task is compiling the complier directly on it, then finish porting my little text editor (currently in C) to it.

I could use BBC Basic with its built in assembler to generate the assembly stuff for the lower level OS, but it's 65C02 only and I need 65816, so I'll be looking to write an assembler in BCPL for it at some point.

Running a 32-bit VM on a 16 bit micro with an 8-bit data bus is never going to be the fastest thing, but here is 1000 digits of Pi it calculated in just over 11 minutes as part of my testings... And there is a Mandelbrot here https://unicorn.drogon.net/mand.b.txt that runs in about 14 seconds. (these are interesting diversions, but do make good testing programs when you can run them on other platforms and compare the outputs)



Ultimately I want to port a BASIC interpreter I wrote in C a few years back to BCPL with the aim of making it a compiler producing the bytecode that the underlying BCPL system uses. It would never be as fast as BBC Basic (nothing ever will be!) but it would be nice to use my own BASIC on a 'micro' rather than my Linux desktop.

Cheers,

-Gordon

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Gordon Henderson.
See my Ruby 6502 and 65816 SBC projects here: https://projects.drogon.net/ruby/

I normally cross-assemble, since Ittiara(my system) isn't great to code on at present, and it's a bit annoying to get it to write to its own EEPROM (I've not set up an easy way to do that yet). The fact that it doesn't have any real external storage capability doesn't help either.
I haven't written an assembler, but I have used a couple of them that run on the 65c02 that other people have written.

The A1-Assembler is an assembler written for the A-One(a re-implementation of the Apple 1), by the same person who wrote the SB-Assembler(which I curently use). It relies on the Woz Monitor, though an extended one known as EWOZ also works for the purpose, and I think it should be relatively easy to replace.
Tali Forth 2 isn't quite a traditional assembler, but it includes a set of words for laying down machine code in a Forth word, sort of like BBC BASIC's built-in assembler.

Although I don't have my own SBC (yet), a major goal of developing PLASMA was to be able to run it on the metal. Similar to drogon's approach, PLASMA (taking many cues from BCPL and later B) is simple enough to compile in a single pass in-memory. Building programs up from smaller compiled modules and run-time linking reduce the need for creating large monolithic binaries.

The edit-compile-run cycle is quite fast on an 8 MHz 65802 and solid state storage. It is still reasonable on a 1 MHz 6502 and floppy drive - not the forever nightmare of Aztec C on floppies or the patience-testing of UCSD Pascal.

I admit to still cross-building the base system on modern HW, but nothing beats sitting down to a proper keyboard for non-distraction coding.

I do develop code directly on my build in Forth, using a 6522-attached micro-SD card as storage. I have a nearly-complete assembler hosted on the build too (nearly complete means that's opcode-complete but needs some work for both the label table and for actually outputting executables) but for the most part, I'm cross-assembling from my laptop.

Given that my machine doesn't have its own keyboard or display but that I'm talking to it through a serial line from my laptop already anyway, that seems like a natural thing. Plus, developing on the laptop means access to git, to backups, etc. I want to get the machine to the point where it's self-hosting but I suspect that there will always be multiple platforms involved in the larger process.

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Mite 6502: http://www.dourish.com/projects/mite.html

I cross assemble, as modern assemblers are much more powerful than that sort that we hosted on 6502 builds.

But when I program in Forth I often code directly on my SBC.

This is exactly what I wanted to do! My aim was to build a computer which was kinda equivalent to what one might have bought for the home in the early 80s - so one had to be able to program on it without another host.

The initial work had to be done on a PC - I used an assembler called AS65 by Kingswood Consulting.

What I built with that assembler is a fairly comprehensive version of BASIC from scratch - which by the way I call dflat as a humour homage to a well known language from Microsoft!

I could have ported the many BASICs and other languages, but part of the motivation was self-learning and hobby.

So now I had a computer that I could program on without any external host... so I have written a few small games just to show that it is a viable language..

I wrote a reasonably good (IMHO!) version of Tetris, which I actually play from time to time!

Recently I decided to add an inline assembler to dflat - so now the language is getting close to the capabilities of the awesome BBC BASIC

This let's me make even better games / real-time programs on my homebrew machine. But defining graphics is a pain, so I am writing in dflat a character editor to allow me to build all my graphics and save it away as a font file. This will be a genuinely useful tool for me - built without an external host..