Subject: Re: uVAXII with Emulex 2nd
To: Anders Magnusson <ragge@ludd.luth.se>
From: Johnny Billquist <bqt@Krille.Update.UU.SE>
List: port-vax
Date: 09/28/1995 18:08:57
>> what to say about  " csr " ? is it an IO-Adress ?
>> 
>Yes, it is.

"Control and Status Register" to read out the TLA. :-)

>> why the difference between the table and the kernel ?
>> 
>:-) This is of historical reasons. Actually the I/O space is only
>a 8K window, and this uses to be referenced as 760000 - 777777 octal.
>(It is the highest 8K in the 18 bit Unibus). Stripping the highest
>2 bits and writing 172150 does mean the same as 772150.

And, of course, on a 16 bit Unibus, the addresses really are
160000-177777... :-)

(The Unibus was designed for a 16-bit machine, and the first one only
had a 16-bit unibus. MMU was added later, along with two more bits.)

And yes, it's very much history... :-)

	Johnny