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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|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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