9 Feb
2022
9 Feb
'22
4:34 p.m.
On Wed, Feb 9, 2022, 5:16 PM Rod Smallwood via cctalk <cctalk at classiccmp.org>
wrote:
Hi
We have narrowed the problem down.
Its the instruction decode ROM's that are the issue.
The images of those are whats needed.
Do those chips have ROM numbers on them? 23-xxxxx is the usual format...
Warner
Regards Rod
On 09/02/2022 23:14, Sytse van Slooten via cctalk wrote:
the rom images are in other files/modules - in some kind of straight binary
format, I'd guess.
>>> On Tue, Feb 8, 2022 at 7:04 PM Warner
Losh <imp at bsdimp.com> wrote:
>>> I found
>>>
https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporat…
>>> which has the source code...
>>>
>>> But I couldn't find the tools to use these files to create microcode
>>> images.
> Actually, the "m8266_ucode.v.txt" there seems to actually be the
program that
> produced the symbolic dump (which is also
available at:
>
> http://www.bitsavers.org/pdf/dec/pdp11/1134/m8266_ucode.out.txt)
>
> It looks like the program is in VHDL or something like that, but it
doesn't
> seem to have the actual microcode (was it
stored/defined in another VHDL
> file?); that raises the question of where the actual microcode that it
was
dumping
was.
It's Verilog (the 'other' hardware language besides VHDL), and
indeed
I'm properly intrigued why someone would choose to do this - which seems
to be
mostly listing the microcode in a readable format - in Verilog.
Unless of course it would be with a long term goal of using that microcode
in an emulator that is sufficiently like a 'real' 11/34 to run it
unchanged. I wonder if that is the case, and what became of the project -
since the files are from 2014, it's probably safe to assume it got stuck
somewhere along the way.
Somewhere way down on my list of things to explore is something similar
but then
for the 11/70 - to make a vhdl version that is microcode
compatible with the original, unlike the current pdp2011 that's 'only'
functionally compatible. And this is about exactly the same way I would
start - except I don't have the '70 rom images yet... If anyone has them
and is willing to share, drop me a note ;-)
Cheers
Sytse