Re: Virtual Memory (Was Re: Kernel 1.14.7 available)

[Michael Schwingen <rincewind@tubul.dascon.de>]

On Thu, May 28, 1998 at 12:21:52PM +0200, Johan Klockars wrote:
> > > Tha Falcon VDI could[1] be able to work without the blitter as long as you
> > > do not use more than 16 colors.
> 
> Why would that be so?

Because there are no soft-blit routines for the new falcon video modes.
However, the old routines (esp. monochrome) should worked.

> If anything, I'd expect the blitter not to be used in true colour mode, but
> eight bit should be handled the same as any other bitplane mode.

This might be true - I am not sure which mdoes exactly would be supported
and which not.

> There has never been a way to 'turn off' the blitter, only to stop the VDI
> (and LineA) from using it. Since no Falcon was ever produced without a

That's what I meant when saying 'turn off'. Since we are talking about VDI,
other programs which directly access the blitter do not count.

> blitter, I guess it made sense not to include the 'blitter emulation' code.

Right.

> The AES always TRAPs to the VDI for output, but the VDI itself has little
> reason to do so. The standard VDI probably uses LineA (why else would it be
> there?), however, so it might be enough to patch that.

Um - No. It seems there is no really separate VDI and LineA - it is both
mixed together, with no clear boundary which is crossed only by $A00X calls
or similar.

> I'd be very surprised if the majority of people have _bought_ a replacement
> VDI (that would've made for a _huge_ profit margin on NVDI) and it would in
> any case be a lot better, IMO, if MiNT could be used without relying on
> non-free software.

Better - yes. However, if it shows that there is no alternative, it is
better to rely on NVDI or similar and have the functionality than missing it
altogether.

BTW: returning to the beginning of this discussion: It should be enough to
only use ST-RAM for blittable memory. There are enough machines where the
blitter can't access alternate RAM (eg. ST/STE with Magnum and other ALT-Ram
cards, Falcon with Afterburner).

Which programs *are* using alternate RAM for Icons etc.? Can't we fix these
instead of turning of the blitter?

cu
Michael
-- 
Michael Schwingen, Ahornstrasse 36, 52074 Aachen