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pubby / nesfab

Programming language that targets the Nintendo Entertainment System
GNU General Public License v3.0
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mapper 189 reset vector doesn't point inside $E000-$FFF9 #26

Open fractal161 opened 3 months ago

fractal161 commented 3 months ago

To reproduce, build the included mmc3 example, but replace the mapper with 189. The reset handler will be at $8161, but it should* be somewhere in $E000-$FFF9. This was tested with the most recent commit on b1.4.

*note: i actually don't know if this is true for 189. my current project currently builds the rom using mapper 189, then patches the header to make it mmc3 to keep the rom size small, so i desire mmc3 behavior here. having the reset vector pointing in a bad location seems to affect kryzsiocart users.

pubby commented 3 months ago

Hmm I'm a little confused. I believe mapper 189 uses 32K banking a la BNROM, so I would assume the reset can be anywhere from $8000 onwards. If this is just a krysiocart glitch then I don't mind altering it though. Let me know if I'm mistaken.

pubby commented 3 months ago

I've pushed a change to b1.4 regarding this