On Wed, 30 Oct 1996, Nigel Pearson wrote:

> * Quadra 840av history (which Bob already knows about):

Great!  It's nice to know someone's finally porting bsd to my machine!

> 	Note that, as the machine starts executing the kernel image,
> 	there is a blast of noise from the Quadra's speaker.

I'm gonna have to give this a try now...  ;)

> 	Bob suspected that the Video address 0x50100700 is bogus,

My video address is 0x60b0/0000, in fact I thought my oly LC3 had the 
same address.  I guess it's been awhile.

> 	Because this particular machine has VRAM which is shared between
> 	main monitor and video I/O systems (and possibly DSP), I am
> 	inclined to accept that some addresses could move around a lot.

I don't think the VRAM is shared over the DSP, because that has its own 
RAM space (or so I thought).  The DSP address should be available from a 
ROM trap, but I don't know which.

> 
> -------	Does anyone know what sort of MacOs code fragment I need to run
> 	to poke around at the Video base addresses?

I would suggest the simple C code:  (MacOS)

GrafPort g;
QDPtr x;

OpenPort(&g);  /* initializes a drawing port based on current monitor values */
x = g.portBits.baseAddr;  /* grabs the address of that video screen */

--Rick C. Petty,  aka Snoopy                <h1><blink>I hate Netscape!
_______________________________________________________________________
SQL/Perl/Java/HTML/C++ programmer  http://www.itlabs.umn.edu/~pett0019/
pett0019@gold.tc.umn.edu, pett0019@itlabs.umn.edu, rpetty@future.i5.com