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From: lockemer@iccgcc.decnet.ab.com
Newsgroups: comp.sys.cbm
Subject: C-128 programming questions concerning memory and ML
Message-ID: <685.26dbd201@iccgcc.decnet.ab.com>
Date: 29 Aug 90 19:32:33 GMT
Lines: 43


I need some help in three areas of 128 ML programming.

1) I am trying to figure out how to use bank switching properly. Some questions
I have are:

- Can you transfer control to another bank configuration that will block out
  the area of memory that the program is currently executing in? If so, how?

For example:
             Bank 0                 Bank 15
	+---------------+       +---------------+
$ffd2	|LDA #0		| $ffd2	| BSOUT ROUTINE |
	|STA $ff00	|       |		|
	|JSR $ffd2	|       |               |

I don't think this works since when the bank is switched to 15, it would not
get to execute the jsr $ffd2, right?


2) Could comeone explain the purpose and/or benefits of relocating zero page
   and explain how to do it? What I don't understand most is, once zero page
   is relocated, does the system use this new zero page as well, or does it
   still use the original zero page? I'm concerned about what happens when
   interrupts take place. If it uses the new zero page, then is it necessary
   to copy values from the original zero page to the new location to prevent
   the system from going off in the weeds? Or do you simply avoid all these
   problems by disabling interrupts?


3) I am writing a program that needs to periodically load new code in, and that
   requires manipulating stored information from these many different sections
   of code. Is there a general strategy for organizing such a program in memory?
   That is, is there a certain structure that can be used which is the most
   efficient where variables are put in one section/bank of memory, the code to
   load new routines in another, and an area for loading new code? At the same
   time I am concerned about being able to access the kernal routines (related
   to (1) above).

   Any comments, suggestions, or most of all solutions will be greatly
   appreciated.

   Todd F. Lockemer