Numpty Bank Switching Question...

[andym00]

If I support standard 130xe banking , is that going to work on everything that actually matters ?

 

What I mean is, banking schemes all kind of support this method right ?

 

(null)

[Rybags]

130XE banking (CPU, not Antic) should work on any XL/XE >=128K. Some expansions don't support seperate Antic access at all.

 

Detecting extra RAM isn't that hard, I've done a program that sets up a table of valid banks although it's not 100% usable yet since I forgot that some expansions actually remap other parts of main RAM to some combinations.

 

Pretty much what it does is write the PORTB value to locations $4001 and $7FFE in a loop from 01 to FF (step by 2 so the OS is always in) then reads them back in a second loop going FF to 01 step -2.

 

I do the check backwards because supposedly Doses that use XRam supposedly use lower bank #s first.

 

It's better programming practice to use a table of bank numbers than assuming that certain bank numbers will be present on systems > 128K.

 

As for Antic access, it'd be a bit more complicated. Easiest method would probably be to set up a situation where a PM collision occurs if XRam is there but main Ram isn't. You'd only need to do it for 1 extended bank, AFAIK any scheme which supports seperate Antic access will do so for every bank present.

[andym00]

I'm not fussed about the antic features, nice as they are, just wanted to be sure that this was in fact the standard method of banking since it's not something I've paid much attention to so far..

 

That separate ANTIC access stuff is all cool and dandy, but personally I'm hard pushed to actually find a proper use for it..

 

Is there anything out there that actually does anything that really pushes the boat out using the separate ANTIC access ?

[Rybags]

AFAIK, a few demos, maybe one game.

 

The usefullness is debatable - it'd have been much, much better if you had a seperate bank register altogether for CPU and Antic, covering everything (ROM too).

 

Actually... I'm using seperate Antic access in Moon Cresta for the star background.

 

Although we're talking VBXE-handled banking here which is somewhat different.

Edited February 25, 2012 by Rybags

[andym00]

Hmmm, like the VBXE banking after playing with it a bit now..

If only every machine had a VBXE in it