Re: 1541 ROM areas recognition

From: Groepaz <>
Date: Thu, 7 Nov 2013 00:39:31 +0100
Message-Id: <>
On Thursday 07 November 2013, you wrote:
> On 6 lis 2013, at 22:44, Groepaz <> wrote:
> >> Is there a reliable, software way of recognising ROM areas of a 1541
> >> (all models)? I mean without knowing what kind of ROM is actually
> >> installed. I assume that all of them have to cover up to the end of
> >> 6502 address space (if not for anything else then at least due to h/w
> >> vectors) but what about the starting point(s) and what if there happen
> >> to be some non-contiguous chunks?
> > 
> > not sure if i understand the question correctly.... but to find out if
> > there is rom or ram at a certain address, write to it and see if the
> > value changed? (backup/restore the original value ofcourse)
> Well, finding RAM would be as easy as you wrote. What is needed though is
> to distinguish ROM from all other (than ROM) types of things that may
> dangle around the corners of address space. Not only RAM. Those may be RAM
> but also e.g. port chips, gaps, unconnected address ranges..

it would be easier to give an advice if you'd tell what exactly you are trying 
to do.... i have only ever needed something like that to find out how much RAM 
is installed in the drive and where it is located - all other info is known 
anyway (like location of i/o chips).


Every programmer knows the answer: $2b or (not $2b) is $ff.

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Received on 2013-11-07 00:00:56

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