Motorola 6809 emulator in JavaScript | Hacker News Reader

Motorola 6809 emulator in JavaScript

github.com

18 pointsmmaly11 comments

Excerpts from Wikipedia:

Like the 6800, it included an undocumented address bus test instruction with the nickname Halt and Catch Fire (HCF)[

Williams Electronics was an especially prolific user of the processor, which was deployed in arcade hits such as Defender, Joust, Sinistar, and Robotron: 2084. Williams also utilized the processor in many of its solid-state pinball machines; the 6809 CPU formed the core of the successful Williams Pinball Controller. The KONAMI-1 was a modified 6809 used by Konami in various arcade sets such as The Simpsons.

The very first Macintosh prototype, wire-wrapped by Burrell Smith, contained a 6809.

The dual accumulator and dual stack pointer design seem like they would make this one of the most straight forward 8-bitters to program. What home computers used this?

I remember reading about a Hitachi clone that extended it to use four accumulators that could either be paired into two 16-bit accumulators or all joint into a single 32 bit accumulator.

What home computers used this? : http://en.wikipedia.org/wiki/SWTPC

There was also the GIMIX, and of course later the Radio Shack Color Computer. A (ugh single 5.25" floppy) SWTPC 6809 system was my first "home" computer system. Flex was a great simple operating system.

Anyone remember Frank Hogg for CoCo ports of Flex?

FYI, '68 Micro Journal is available online or on CD, though I have a full print set and a few SWTPCs if anyone wants to do a 6809 get together and hackfest at some point.

Flex was great. I disassembled it all to learn its internals. Then implemented print spooling, RAM-disk, and dual tasking by RAM bank switching, for a 6809 based computer I was co-developing. But then the IBM PC took over the world :/

The Radio Shack TRS-80 Color Computer was the most popular home computer in the USA to use the 6809.

http://en.wikipedia.org/wiki/TRS-80_Color_Computer

Motorola intended the 6809 as a transition between their popular 6800 series and the future 68000 line. The '09 could execute 6800 code with minimal modification.

I learned BASIC, Forth and 6809 assembly on one of these. Fond memories.

You are right. The 6809 was relatively straight forward to program. It had a highly orthogonal architecture which made it a very effective and pleasing framework to think in.

My home made one that I got working in 1981. A friend had built a machine around a 6800 and I had used the 6800 during a vacation job at Ferranti. The single index register of the 6800 was a pain. One was always swapping indexes between X and RAM. Should I build a 6800 machine and suffer? The 68000 was being talked about and was going to be a lovely machine for assembler programmers, somewhat like the IBM360. But that could be a long wait for a processor which might be beyond my budget at first.

So I went with the 6809. It was enough of an improvement over the 6800 to be bearable and available and reasonably priced.

(The 6502 had two index registers, which was nice, but they were 8 bit, and I had ambitions to write a Lisp for my machine and would certainly want 16 address registers.)

>What home computers used this?

In France, the 6809 was used in several computers (TO7 for example) widely deployed in schools and also purchased by many: my parents bought me one. For its time it was nice, but I cannot help thinking than RISCs are more 'elegant'.

I thought it was going to be a transistor-level one, like this: http://visual6502.org/wiki/index.php?title=Motorola_6800

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