Looking at my inventory, I seem to have no less than four spare M8266
(plus one in my 11/34 that runs, plus probably another in my 11/34 out
in the garage.)
Rod, where are you located?
JRJ
On 2/9/2022 6:16 PM, Rod Smallwood via cctalk 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.
Regards Rod
On 09/02/2022 23:14, Sytse van Slooten via cctalk wrote:
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%20Corporation/08%20PDP-11/01%20PDP-1104-1134/05%20PDP-1104-1134%20Microcode/
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
the rom images are in other files/modules - in some kind of straight
binary format, I'd guess.
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
