[Simh] vax780 bare metal - rq addresses --> rq registers

[Mike Stramba]

On 5/13/20, Mark Pizzolato <Mark at infocomm.com> wrote:
> And there is:
>
>          sim> SHOW UBA IO
> or
>          sim> SHOW -o UBA IO

What are those showing ?

It seems to be the last address in the range shown by SH <dev> ?

>
> Maybe you can explain more about where you going with this...

I'd like to understand how the vax device drivers and system internals
operate at the
most basic "primitive level" .....   just for fun ;)

And how the simh commands relate, so that I can debug my low-level experiments.

E.g. what I need to Deposit  where  to do I/O with the various devices.

I.e. how it compares to IBM 370 /390  (io / channels SVC  interrupts  etc)

I have the BSD  ver 7 source, with the sys directory looking like the
most interesting.

Mike

>
> - Mark
>
> On Wednesday, May 13, 2020 at 5:23 PM, Johnny Billquist wrote:
>> Oh, and yes, there might be issues with 32 bit access, since the Unibus is
>> only
>> 16 bits wide. Also, you might need to enable the Unibus adapter before
>> you
>> can get to anything sitting on it.
>>
>> I can't remember the details, but the documentation for the Unibus
>> adapter
>> (DW780) is also on the net, so you just have to look it up...
>>
>>    Johnny
>>
>> On 2020-05-14 02:18, Johnny Billquist wrote:
>> > It's a little complicated, because the controller is on the Unibus,
>> > and the Unibus only have an 18-bit address space.
>> > So the SBI Unibus adapter contains a mapping between the VAX address
>> > space, and the Unibus address space, and the UBA also contains mapping
>> > for DMA, which must be set up before playing around. So there are
>> > layers you need to go through.
>> >
>> > Also, the MSCP controllers only actually have two registers on the
>> > bus, and they are only really used for anything more advanced than
>> > just getting the attention of the controller at initialization. After
>> > that, all communication happens through buffers.
>> >
>> >    Johnny
>> >
>> > On 2020-05-14 02:14, Mike Stramba wrote:
>> >> What is the relationship / mapping between the addresses displayed
>> >> for the SHOW RQ  (disk controller) command and the listed registers
>> >> in the
>> >> vax780 manual ?
>> >>
>> >> E.g  SA, S1DAT, CQBA etc ?
>> >>
>> >> i.e. Does the SA register appear  /  is accessed at 2013F468 ?
>> >>
>> >> S1DAT at 2013F46A  .... etc ?
>> >>
>> >> If so, are those addresses not accessible with EXamine / Deposit ?
>> >>
>> >> sim> ex 2013F468
>> >> Address space exceeded
>> >>
>> >> Only from an instruction ?  :
>> >>
>> >> e.g.
>> >>
>> >> MOVW R0,2013F468
>> >>
>> >> sh rq
>> >> RQ    address=2013F468-2013F46B, vector=1FC*, BR5, UDA50, 4 units
>> >> .....
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>> >>
>> >
>> >
>>
>>
>> --
>> Johnny Billquist                  || "I'm on a bus
>>                                    ||  on a psychedelic trip
>> email: bqt at softjar.se             ||  Reading murder books
>> pdp is alive!                     ||  tryin' to stay hip" - B. Idol
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>