[TUHS] 68k prototypes & microcode

[Michael Parson]

On 2021-02-04 16:47, Henry Bent wrote:
> On Thu, Feb 4, 2021, 17:40 Adam Thornton <athornton at gmail.com> wrote:
> 
>> I'm probably Stockholm Syndrommed about 6502.  It's what I grew up on, 
>> and
>> I still like it a great deal.  Admittedly register-starved (well, 
>> unless
>> you consider the zero page a whole page of registers), but...simple, 
>> easy
>> to fit in your head, kinda wonderful.
>> 
>> I'd love a 64-bit 6502-alike (but I'd probably give it more than three
>> registers).  I mean given how little silicon (or how few FPGA gates) a
>> reasonable version of that would take, might as well include 65C02 and
>> 65816 cores in there too with some sort of mode-switching instruction.
>> Wouldn't a 6502ish with 64-bit wordsize and a 64-bit address bus be 
>> fun?
>> Throw in an onboard MMU and FPU too, I suppose, and then you could 
>> have a
>> real system on it.
>> 
>> 
> Sounds like a perfect project for an FPGA.  If there's already a 6502
> implementation out there, converting to 64 bit should be fairly easy.

There are FPGA implementations of the 6502 out there. If you've not seen
it, check out the MiSTer[0] project, FPGA implementations of a LOT of
computers, going back as far as the EDSAC, PDP-1, a LOT of 8, 16, and 32
bit systems from the 70s and 80s along with gaming consoles from the 70s
and 80s.

Keeping this semi-TUHS related, one guy[1] has even implemented a
Sparc 32m[2] (I think maybe an SS10), which boots SunOS 4, 5, Linux,
NetBSD, and even the Sparc version of NeXTSTEP, but it's not part of the
"official" MiSTer bits (yet?).

-- 
Michael Parson
Pflugerville, TX
KF5LGQ

[0] https://github.com/MiSTer-devel/Main_MiSTer/wiki
[1] https://temlib.org/site/
[2] https://temlib.org/pub/mister/SS/