Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.sys.apple2.programmer > #296

Re: standard interface to aux RAM or RWIII RAM?

Show all headers | View raw

On Thursday, May 10, 2012 6:07:56 PM UTC-7, aiia...@gmail.com wrote:
> any ideas?  

page 7-3 of Beneath Apple Prodos has a Memory map of Prodos.

Prodos Kernel occupies $d000 to $FFFF RAM in the LC area.

How to interpret the rest of the memory map?

for instance, where is the quit code???

what is the other RAM area to the right of the aux RAM
graphic?


there are two large areas of RAM to use.  lower 48k, Upper
16k(LC, language card area)

In the lower 48, you can choose to read and write
to main/aux.  You can read from main, write to aux,
etc..

in the Upper 16k, you choose to READ/WRITE to aux
or MAIN.  You cannot read from one and write to the
other directly.

It looks like the LC area is the best place for a
program that wants to access a large amount of 
DATA (the lower 48k).  If you want access to other
RWIII AUX pages, you would need to put your program
in those other AUX LC areas (upper 16k)

Using the lower 48k for program, you can access
multiple LC areas, but each time you switch a new
one in, the stack is retrieved from that bank.

I am working on making an animated GIF to show
how the softswitches work, what is where, and the
boot process.

It would be nice to have a CC65 library that is
standard, so RWIII can be accessed easily from
a C or asm program.

Back to comp.sys.apple2.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-10 18:07 -0700
  Re: standard interface to aux RAM or RWIII RAM? David Schmenk <dschmenk@gmail.com> - 2012-05-10 19:41 -0700
  Re: standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-11 09:31 -0700
    Re: standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-11 17:42 -0700
      Re: standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-12 15:31 -0700
        Re: standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-12 15:58 -0700
          Re: standard interface to aux RAM or RWIII RAM? "ict@ccess" <gids.rs@sasktel.net> - 2012-05-21 20:53 -0700
            Re: standard interface to aux RAM or RWIII RAM? aiiadict@gmail.com - 2012-05-25 16:19 -0700

csiph-web