pdp 11 boot rom 23-E39A9

[Don North]

Dave McGuire wrote:
> On Sep 27, 2007, at 2:59 PM, Don North wrote:
>>>> My semi-yearly reminder....
>>>>
>>>> Would anyone have the DEC boot rom for the M9312 that boots off 
>>>> TMSCP TK50 &
>>>> TU81 (MU)? Please check your M9312 boards and your PDP-11/44 boot 
>>>> roms for
>>>> rom "E39A9" or part number "23-E39A9".
>>>>
>>>> If you have it, I (and a few others) would love if I could borrow 
>>>> it to make
>>>> an image.
>>>
>>>   Is this not it?  (Am I missing something?)
>>>
>>> http://www.koders.com/noncode/fid5430B733F8815278811DA087D7331E72216E0CDB.aspx 
>>>
>>
>> One would think that this is it, but alas it is not :-(
>>
>> I did a download and disassemble, and it is just a copy of the DU 
>> (23-767A9) boot prom image.
>>
>> In fact, download both 23-767A9 and 23-E39A9 and compare them; they 
>> are EXACTLY the same image.
>>
>> I believe this happened because there is an image named 
>> 23-E39A9.hex/bin floating around
>> various sites that actually is just 23-767A9 (DU, MSCP boot) renamed.
>
>   Crap.
>
>   Source code to that ROM has to be around somewhere.
>
>         -Dave
>

I dunno, I think it was saved on /dev/null from all that I can tell.
Even if a binary exists it is easy enough to disassemble and recreate a 
source.
I have a version that I have recreated (from the logic in the SIMH TMSCP 
driver boot
code) but the smallest I can get it down to is 5 words too large for the 
available
ROM space :-( and even then I had to cheat a little bit to get it that 
small.

I'm *really* interested to see what tricks DEC played to implement the real
TMSCP boot PROM for the M9312. The MSCP PROM source is available and 
they did
some really groady (cool) hacks (depends on your point of view) to use 
words as
both instructions and data.

Don