CBM-II / B-Series ML Programming

From: Rob Clarke <crock_at_clarke-family.org.uk>
Date: Sat, 27 Apr 2013 00:52:42 +0200
Message-ID: <517B053A.9000800@clarke-family.org.uk>
Good evening Gentlemen,

For some time I have had a low priority project to port some ML games to 
the cbm-II/b series. As an initial step, I wanted to understand the 
banking routines that the kernal uses to see if I could make use of 
them. I found Jim Butterfields' article in the July '83 issue of 
Transactor but I'm a bit confused.

First, it is unclear to me whether the kernal creates the mirror of the 
routines in the banked RAM or whether this is done manually. Second, the 
entry point referenced in the article at $FEA7 does not correspond to 
any of the versions of the b-series ROM's I could find on zimmers. 
Finally, the false jump table of the kernal vectors above $FF80 should 
supposedly jsr to the same location (again, $FEA7), with the stack 
return address being used to identify the correct routine to call. 
Again, it is not clear to me whether I have to create the jump table or 
whether the kernal does this?

All this makes me think I missed something - can anyone point out what 
it was?

Here's the transactor issue. Jim's article begins on page 60.




       Message was sent through the cbm-hackers mailing list
Received on 2013-04-26 23:00:15

Archive generated by hypermail 2.2.0.