
The KK Computer: A Radical 6502 Redesign - ingve
http://laughtonelectronics.com/Arcana/KimKlone/Kimklone_short_summary.html
======
Dr_Jefyll
Thanks for posting, ingve (and 0x12). 0x12's HN thread [1] about my project
included the following TLDR:

"Guy expands 6502 to 16M address space by intercepting the databus and re-
mapping unused opcodes and clever use of the spurious signals generated by the
cpu when executing other undefined opcodes, adds a few registers to make the
whole thing transparent from an assembler programmers point of view. In other
words, there is no difference to the programmer between native and newly
minted instructions.

On top of that he boosts the speed of his forth interpreter by concentrating
on a frequently used construct called 'NEXT' in a way that should make anybody
that has tried to optimize the inner loop of some VM or language proud. After
all, what better way to optimize in such a situation than to be able to mold
the instruction set to your desire.

He then uses this home-brew Frankenstein contraption as his benchtop computer
for multiple years to do real work (instead of just shooting some pretty
pictures and calling it a day)."

[1][https://news.ycombinator.com/item?id=3070169](https://news.ycombinator.com/item?id=3070169)

HN folk may recall a project much _less_ ambitious than the KK Computer which,
for some reason, attracted far _more_ online attention!

One-bit Computing at 60 Hertz [2]

[2][http://laughtonelectronics.com/Arcana/One-
bit%20computer/One...](http://laughtonelectronics.com/Arcana/One-
bit%20computer/One-bit%20computer.html)

[3][https://news.ycombinator.com/item?id=12469790](https://news.ycombinator.com/item?id=12469790)

~~~
zentiggr
Regardless of its quirks, I loved the 6502 when I was writing my revision of
the onboard ROMs. Easy to get the scope of the instruction set, etc. Having
this set of expanded capability would have been game changing... maybe a riff
off GEOS, or writing an Echelon clone with Minecraft size worldmap...

The mind boggles, and wonders if I just started my retirement project
planning.

------
jacobush
I wonder if there'd be any practical use of this enhanced 6502 in the modern
world? Implemented in VHDL/Verilog perhaps?

~~~
rollcat
I really really doubt it. "Because it's cool" seems to be the only reason /
motivation.

~~~
Dr_Jefyll
Back in the day (late 1980's) there was ample motivation as I had no knowledge
of or access to the 65816. Programmable logic has changed the landscape since
then -- and btw I _have_ whimsically contemplated a modern re-issue of the KK.
(I've also contemplated some KK-ish hacks that would yield an improved 65816!)
But I agree the scope for practical application has shrunken. In the first
place you'd need to be committed to the 65xx family, because alternative,
modern processors offer compelling advantages not featured by 65xx.

That said, KK has features not present on the 65816, and in certain
applications these could be pivotal. Obvious examples include the NEXT
instruction and the new addressing mode. Less obviously, KK preserves the
65C02's bit-manipulation instructions, which can be a boon in I/O-intensive
code. The '816 sacrificed these opcodes to make room for alternative, also-
worthy objectives.

