On 2013-11-07, at 00:39, 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.... NP - I once wrote a simple drive-ROM dumper program, which works fine as long as I modify it every time a different ROM layout pops up. Which is of course that I need to know the layout in advance. Which means either knowing what's inside or opening, checking, analysing, ... I am thinking (wishfully - probably) of making the program universal in the sense that it could detect ROM areas itself. > 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). Not really. DD3 equipped 1541 is a good example of a situation when this does not hold true. It has different I/O location (the parallel port PIA), different RAM size/location and different ROM size/location. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2013-11-07 15:00:05
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