"michael@camaronet.de" "Michael Kukat"  wrote on 4-MAY-1999 16:51:34.03

>Hmmm. Maybe. If i find the time. But first i want to complete my VS 4000
>VLC port (cache still doesn't work, don't know about initialization, and
>uninitialized, the machine doesn't run very long).

Well VLC uses the SOC chip and only has the primary on-chip cache i.e. there is
no other cache in the system. Any document that describes the SOC chip will do
nicely, just in case you don't have one here is a summary:

IPR 0x25: Cache Control register (CCR)
	bit 2: enable cache
	bit 1: flush cache
	bit 0: diag mode

When diag mode is on you can write to the cache data happen in the range
0x20150400-0x201507ff and tags in the range 0x2015000 to 0x201503ff

BEHR (0x20150800) (LW access only)
	bits 0:7 - enable each of 8 banks (turn all on)
	bits 8:15 - read only bank hit bits used for testing

To turn on the cache do something like:

a) Set CCR bit 0 to 1 to enable diag mode
b) enable all banks in BEHR
c) write all tags with V=0
	This has now effectively flushed the cache
d) turn off diag mode and turn on the cache (I think you can do this in one
   go by writing 0x04 to IPR 0x25.


If you need more detail pick up EK-KA660-TM KA660 CPU Module Technical Manual.
This is for the VAX 4000-200 ignore references to a backup cache since the VLC
doesn't have one but the VAX 4000-200 uses the same SOC chip as the VLC so the
primary cache organisation must be the same and the relevant control registers
must also be the same (I guess ...)

Antonio