Re: [cc65] Romable configuration / run-time library?

From: Ullrich von Bassewitz <>
Date: 2013-01-18 23:35:52
On Fri, Jan 18, 2013 at 04:39:06PM -0500, Darryl Sokoloski wrote:
> >  The zero page locations used
> >  by the runtime should be choosen so that they don't interfere with other
> >  code that might be running (the kernal for example).
> I'm not sure how to do that.  Should using $1A as above leave enough
> space for the kernal and it's IRQ handlers?  Is there a method I can
> follow to determine what that value should be?

If nothing else runs on the hardware, you can choose whatever address you
like. If a ROM is in place that is called from C code or that handles
interrupts (which is usually true for the CBMs), the ROM routines might modify
zeropage locations also used by the runtime, so the code will run into

So one needs some knowledge about the machine in question when choosing the
locations for the zero page. I suppose $55 and following should be ok, if the
pet library uses these addresses.



Ullrich von Bassewitz                        
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Received on Fri Jan 18 23:35:59 2013

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