M9301-YB Bootstrap/Terminator ROM dumps / listings?

Don North north at alum.mit.edu
Thu Apr 30 14:18:30 CDT 2015

On 4/30/2015 9:55 AM, Johnny Billquist wrote:
> On 2015-04-30 17:06, Noel Chiappa wrote:
>>      > From: Jorg Hoppe
>>      >> Here's what I have so far:
>>      >> http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/M9301-YA.mac
>>      > Thanks for that effort!
>> Eh, de nada. Interesting and educational.
>>      > The M9312 code should be similar, at least it may expose some ideas
>> Some parts of it (e.g. the CPU diagnostic) are mostly identical (and the
>> comments there, particularly on the single-op register instructions, are
>> useful to total understanding of that code in the M9301); but alas, I had
>> already done that part of the M9301 (at least, at a surface level)!
>> Much of the M9312 (including the functionality of most of what I had yet to
>> read in the M9301) was quite different. I did manage to get the 'print
>> number' code out of it, but that was pretty much it.
> I thought I had seen the sources of the bootstrap code in some document. Did I 
> just imagine that?
> I hope you also are aware that both the M9301 and the M9312 have different 
> boot roms for some machines. I know that the 11/70 use different roms with 
> other tests than other PDP-11s, and I seem to remember that one or two others 
> do as well. (The 11/60 keeps popping up in my brain...)
>> So I've done a lot of the remaining M9301-YA code (new version uploaded to
>> location above); not the per-device code, I'll probably blow that off, but
>> other than that, only a few tiny sections remain to be understood.
> The per-device code are in separate PROMs that are used in both the 9301 and 
> 9312. Those are the ones with the device code as constants in the beginning of 
> memory space for the PROM, by the way. (I seem to remember someone mentioning 
> this in the past.)
>     Johnny

The M9312 device boot proms are totally different format and structure than the 
M9301 proms. Not interchangeable.

The M9301 has four 4b wide proms configured as a 512x16 and the console and 
device boot code all live in this address space.

The M9312 (and the 11/44 also) have one 4b console PROM, and four slots for 4b 
wide device boot PROMs. Each of the PROMs are nibble accessed to build a 16b 
word from four 4b nibbles. The PROMs are all independent of one another.

The 11/44 module has its own console boot code PROM, but it uses the standard 
M9312 device boot PROMs.

For the M9312, there are two console PROM variations, one for the 11/04/34/etc 
class machines, and one for the 11/60/70.


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