Re: [cc65] Atari Extended Memory Driver Anybody?

From: Oliver Schmidt <>
Date: 2012-09-04 10:55:54

> I've finally finished the basic 128k 130XE compatible EMD driver for the
> Atari 8-bit.

Cool :-)

> Overlaydemo needs to be altered slightly though, since the
> Atari 8-bit only allows 8 character filenames (call the overlays overdemo.1,
> overdemo.2, overdemo.3 for example).

I can't follow you here. Are we talking about the current cc65
snapshot? There in overlaydemo.c the files are named "ovrldemo.1" etc
explicitly because of the Atari - and I had that program already
running successfully as-is...

> Doesn't
> check for the availability of extended memory (yet)-just assumes that the
> 130XE banks exist and are available.

The idea of multidemo.c is to fall back to "ordinary" file based
overlays if there's no emd driver found that initializes successfully.
From that perspective it would be great if you could find the time to
add that feature.

I presume if the banks don't exist then writes to memory in that area
just end up written to main memory. In that (usual) case the usual
approach would be something like:

LDA $4000
LDY $<??>
STY $D301
STX $4000
STY $D301
CMP $4000
STA $4000
BNE <Error>
<ExtMem present>

> Emtest.atr: disk image for use in emulator with emtest, overdemo and
> multdemo executables (extension .XEX) for testing.  Some of them go into an
> endless while(1) loop so screen output can be seen... just hit RESET to get
> back to DOS.

I added a cgetc() to the end of both overlaydemo.c and multidemo.c
explicitly for the Atari - they seemed to work for me. Does that
depend on other "things" like EXE type and/or DOS used?

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Received on Tue, 4 Sep 2012 10:55:54 +0200

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