Re: [cc65] To Atari platform coordinator

From: Christian Groessler <>
Date: 2005-07-13 22:19:48

On Tue, 12 Jul 2005, Fatih AygŁn wrote:

> I think I can do something about 320x192x2 graphics
> driver module because it seems that the dirty work is
> already done for c64, so it shouldn't be much burden
> to adapt it to atari. But I don't see a way to protect
> the screen memory from the heap routines in a run-time
> linked module. Do you have any suggestions?

I can only think of a way where the programmer has to indicate that (s)he
will use the graphics drivers. This will tell the startup code to adjust
the heap in such a way, that the heap doesn't overlap the graphics memory.

Currently such a notification is implemented if you use the _graphics()
function in your program. (Similar to the BASIC 'GRAPHICS' command.)
It's done by the constructor of the _graphics() function.

You can set the _graphmode_used variable to the graphics mode you intend
to use in your program. If you don't set this variable, the startup code
assumes the most memory consuming mode.

The code which examines _graphmode_used and adjusts memory accordingly is
only linked into the program, if you use the _graphics() function. Since
the Atari runtime is already quite big (don't say "bloated" :-), I don't
like adding this code unconditionally to all Atari programs.

Therefore I'd like to have this code linked in only if you use the
_graphics() function or somehow indicate you will use the graphics

Uz, do you have a suggestion on how to do this?

> I also think that dio_query_sectcount can be
> implemented using "get config" 'N' command, assuming
> standart sizes if it fails and distinguishing between
> them using "get status" 'S'. This should work for the
> 99% of the cases. Any ideas?

I don't know. I will look into it...


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Received on Wed Jul 13 22:20:15 2005

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