Re: VAX port internals etc...

[Holm Tiffe <holm%freibergnet.de@localhost>]

Anders Magnusson wrote:

> Hi Holm et al,
> 
> now I'm back and can maybe answer a few questions I snapped up in the 
> mail conversations.
> 
> The SIE (0x20040004) is just a number in the firmware PROM that can be 
> used to find out which type of vax it is.  The SID tells only about the 
> CPU architecture, which may differ in available instructions etc...

Yes, know this address since I've patched the bootloader:


-EZA0

2..1..0..
vax_cpudata: a000006
vax_cputype: a
vax_boardtype: a000000
vax_boardtype(sie): a000009
fromnet: 1

The boardtype is the ored thogether CPU Type and the SIE contents...
> 
> The SCB is an array of 64 interrupt handler addresses (vectors). Its 
> content can be found in the VARM in section 6.6.  An interrupt has a 
> specific priority level (there are 32 levels) and a vector to which it 
> is associated.  In NetBSD there is a default handler for all possible 
> vectors, and a specific vector is allocated via scb_vecalloc().  
> Hardware devices usually use levels 0x14-0x17.

Think I got it now.
> 
> You do not need to attach the console driver to any bus at all, look at 
> how gencons is written.
> 
> When init starts it will be the first time the cnopen routine is called.
> 

Looked at it already, but I wanted to use as much as possible from the
sgimips scn driver which has some bus related code in it.
I hope I can modify it so that the same driver is usable for the mips and
the vax..

Currently I'm reading the device driver writing guide for NetBSD from
Jochen, but have not so much time anymore now. This was a bigger" working
gap" after the holydays, now some of my customers want me back :-)
> 
> So, any more questions that I have missed in the massive mail 
> conversations that has been last week? :-)
> 
> -- Ragge

*grin*

Not that much, just a question here an there ...

Regards,

Holm
-- 
      Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, 
     Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583
  www.tsht.de, info%tsht.de@localhost, Fax +49 3731 74200, Mobil: 0172 8790 741