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Posted By

Gaia
on 2009-11-16
16:17:33
 Re: There is no 16k only support

Nice job, Csabo. Another thing sprung to my mind: as I recall, old compressors (or "compacter"-s wink ) were notoriously +4 only.

So, as soon as you "zipped" an old <49 block game, even though it became even smaller than 12kb, it was actually not able to run on a vanilla C16 any longer. This was because the decompressor routine first copied up everything to the end of the expanded (=64kb) RAM which is $FCFF. That is obviously impossible on a C16 (although this address effectively translates to $3CFF, so there is a remote chance that in some rare cases it may actually work).

So one easy fix is to just get rid of the compressing, look for the JMP call in the decompressor code on a 64kb machine (or emulator) and rewrite it to $F445 (jump to monitor). Then you can usually save it directly from BASIC DSAVE or checking $9D/$9E for the end address and use monitor 'S "blah" 8 1000 endaddress'.

I am not sure what recent xplatform compressors exactly do though... (PuCrunch, Exomizer, etc.) so your mileage may vary there, but again there are not that many cracks with those either (if at all).



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