-----Original Message-----
From: cctalk [mailto:cctalk-bounces at
classiccmp.org] On Behalf Of Mike Ross
Sent: Tuesday, May 24, 2016 2:15 PM
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Re: VAX-11/730 and Emulex UC17 woes
On Wed, May 25, 2016 at 8:58 AM, Josh Dersch
<JoshD at livingcomputermuseum.org> wrote:
Interesting, the UC17 has the same firmware
version (G143R) on the label
of the EPROM. I wonder if the contents are identical.
Could you send me a
dump of your ROM so I can compare?
>
> I dumped the memory for this code from the VAX and entered it into
> SIMH to use SIMH as an VAX unassembler and this is what it looks like.
> If the UC17 host resident VAX code is the same, any clues here as to
> what might be causing a halt on the 11/730?
Here's what I found comparing my code with someone else's dump:
I've been working this with Glen Slick. Here's a snippet of a recent email with
him. He provided a dump of the DMAed loader from his UC07:
The raw binary dumped on the VAX looked like this:
<snipped for brevity>
Thanks. Glen sent me his dump and I compared with mine. I have the same three
differences:
D 000002A0 01200880 // 0100F308
D 000002BC 0014688F // FFF4688F
D 000002C0 65B45520 // 65B45500
(commented values are the ones that differ on my machine).
This changes the code as below:
-> 298: MOVL #80000002,@#F30808 (was: 298: MOVL #80000002,@#20088008)
2A3: NOP
2A4: MTPR #1F,#12
2A7: MOVAL 400,R1
2AE: MOVL #200,R2
2B5: MOVL #0,(R1)+
2B8: SOBGTR R2,2B5
-> 2BB: MOVL #FFF468,R5 (was 2BB: MOVL #20001468,R5)
I suspect these values are changed "on the fly" based on the machine type
punched into the SA register as the last step before the "S 80" command; in
particular, the source address for the MOVL instruction at 2BB now makes more sense,
corresponding to a value in the UBA register set for the UC17.
However, F30808 doesn't make sense as the destination argument address for the MOVL at
298. This looks like a map register for an 11/750 (as documented in the UC17 manual as
being at F30800/F30804) and I wondered if it should be similar to the value for the 11/730
(F26800/F26804).
So I changed the instruction at 298 to:
MOVL #80000002,@#F26808
(which corresponds to a change in the value at 2A0 to 0100F268)
On the VAX-11/730 and did an "S 80" and lo and behold, it works!
I suspect either a typo in the manual for the machine type designator word, or a revision
difference between firmware and documentation.
- Josh