Subject: Re: [stella] heurustics for autodetecting bank switching type From: "Andrew Davie" <atari2600@xxxxxxxxxxxxx> Date: Sat, 15 Feb 2003 21:33:18 +1100 |
Just load and run the thing for a few frames. Check the scanline count. if it's 262ish or 312ish, then you've probably got the correct banking scheme. If you have the wrong banking scheme it's highly unlikely a cart will generate a valid frame :) Then cycle thru the available schemes - most likely first - until you get a valid frame. Yeah, I know .... Cheers A ----- Original Message ----- From: "Adam Wozniak" <adam@xxxxxxxxxxxxxxxx> To: <stella@xxxxxxxxxxx> Sent: Saturday, February 15, 2003 8:50 PM Subject: [stella] heurustics for autodetecting bank switching type > Having lots of free time, I began pondering autodetection of bank > switching types (I'm bothered by the increasingly unweildy stella.pro > file size). > > Here are some ideas. Maybe they'll resonate with someone. > > The Cartridge::autodetectType() routine in stella (1.2) is a good > start. > > 3F has been extended by many homebrew authors to do more than 16K carts. > These are not hard to spot. Look for multiple occurances of the byte > string $85 $3F in images of 16K, 32K, etc... I have a large corpus of > files and I did not find many false positives with this heurustic. > > For 8K images, F8 can be spotted with multiple occurances of > {$8D | $AD | $2C} {$F8 | $F9} {$FF | $1F} > (thus $8D $F8 $1F would be a match, as would $2C $F9 $1F) > Not many false positives here. This covers the bulk of the F8 images in > my corpus. > > Similarly, for 16K images, F6 can be spotted with > {$8D | $AD | $2C} {$F6 | $F7 | $F8 | $F9} {$FF | $1F} > > I've yet to come up with E7 or E0 heurustics, but they shouldn't be > hard, and would be similar to these. > > -- > Will code for food. http://cuddlepuddle.org/~adam/resume.html > > adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam/pgp.html > > -------------------------------------------------------------------------- -------------------- > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://www.biglist.com/lists/stella/ > > > ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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