PDP-11/34 CPU PROMS

[Rod Smallwood]

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
>
>