[LispM-Hackers] NuBus?

[James A. Crippen]

On Thu, 5 Apr 2001, John Morrison wrote:

> Hi;
> 
> "James A. Crippen" wrote:
> > Do we need to worry about emulating the NuBus?  I don't think we should
> > need to, but what does everyone else think?
> > 
> > We'll need to emulate the memory for the NuBus, but I don't think we
> > actually need to emulate the NuBus architecture or hardware...
> 
> Does anybody know the answer to this question?  I had supposed we would
> have to (but then, I also thought the interface to the frame buffer was
> a dumb memory-mapped array)...

Actually, from what it seems like there is a dumb memory-mapped array
iface to the fb.  You just need to get a locative to the start of the
array and know the number of pixels per raster line on the screen, and
then you write your own data in.  This exists on the Symbolics lispms as
well.  But the idea of the macroops was to relieve the burden of such
low-level access, and to keep people from needing to do such low-level
direct memory mangling.  And to keep people from shooting themselves in
the foot.

I'm almost certain that TV will probably have some crap in it that does
direct fb access.  It's almost inevitable.  I suppose it'll be worth
looking for.  Considering that setting up the fb is one of the first
things that will happen when the system boots, this will be a bitch to get
right.

'james

-- 
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