Final Fight CD coredump during stage 1 boss battle

[Former user]

Original [issue 232](https://code.google.com/p/genplus-gx/issues/detail?id=232) created by tournier.julien on 2012-07-04T21:17:13.000Z:

1. start final fight cd (j) 2. fight till the end of stage 1 3. during the fight with "Damnd", a few seconds after the character "poison" appeared, just before hitting "damnd", the game crashes with a wii core dump.

I've tried it again and again, it always crashed during this boss fight

i use japanese bios v1.0 for model 1, with all default setting. my final fight cd dump is a dump with audio tracks extracted as .wav file. The game track is a .bin

i don't know if my game iso is a good one. Taken from http://edgeemu.net/details-33511.htm i haven't tried the european and american versions of the game. I prefer this one as it is uncensored and clother to the arcade.

do you need some more informations (photoshot of the coredump ?)

[Former user]

Comment # 1 originally posted by ekeeke31 on 2012-07-04T21:21:00.000Z:

photo of the core dump would be useful yes, it will help figuring where it crashes also a savestate just before the bug occurence so i could try to reproduce it

[Former user]

Comment # 2 originally posted by ekeeke31 on 2012-07-04T23:01:12.000Z:

I think I figured this one (reproduced on the win32 port).

For the record, the main CPU is running code from the end of Word-RAM in 1M mode (PC = $21EF1E) and is executing a PC-relative instruction that somehow make it accidentally read out of Word-RAM area(above $21FFFF). This area is cell image area and can theoretically be accessed but the emulator did not expected this case and mapped PC-relative access there to NULL memory address instead, hence the coredump.

[Former user]

Comment # 3 originally posted by tournier.julien on 2012-07-05T07:45:28.000Z:

Thanks for the explanation you find the root cause quite fast ! I will take a picture of the core dump, save the game states before the crash and post it tonight.

[Former user]

Comment # 4 originally posted by superballena on 2012-07-05T19:03:24.000Z:

Not sure if it could be related, but the European version will stay at the "ROUND 1 CLEAR!" message instead of loading the next level. No core dump whatsoever, though.

Using 2.00 BIOS.

[Former user]

Comment # 6 originally posted by ekeeke31 on 2012-07-05T19:06:27.000Z:

Probably not related...

Damn, I knew I should never have started Mega CD emulation, issues pop up faster than I can handle them, this is hell...

[Former user]

Comment # 7 originally posted by superballena on 2012-07-05T20:01:42.000Z:

Don't sweat it, man. Reaching this level in just one month is pretty impressive.

Some games run flawlessly already, and fixing any others will just be a plus in future updates. We love your work and will help testing as much as we can. :)

[Former user]

Comment # 8 originally posted by tournier.julien on 2012-07-05T20:31:22.000Z:

There's no hurry fixing bugs... take your time. Your work is already much appreciated and it should eat a lot of your free time.

Concerning the freeze on the european version with no coredump, it is perhaps a bad iso. I had a previous japanese iso thats freeze the emulator before the title screen. The emulator was just frozen and the wii drive blue light wasn't blinking anymore. no coredump, just stuck there 'til i reset the wii by myself. It would be better to start a new bug report until it is confirmed, rather than mixing the 2 issues.

[Former user]

Comment # 9 originally posted by ekeeke31 on 2012-07-05T21:30:28.000Z:

I know yes, it's just that I hate knowing bugs are there and do nothing ;-)

For the record, the freeze when loading next level is because of missing audio tracks (or more exactly invalid CD TOC). The same occurs at game over screen if you don't press continue. Does the same in Kega if you load an iso without any audio tracks.

I guess more games rely on accurate TOC or will freeze at some point...

[Former user]

Comment # 10 originally posted by tournier.julien on 2012-07-05T22:32:49.000Z:

Here is a save state just before the coredump.

It took me a lot of retries before triggering the bug tonight... i even came accross the bug described by superball after defeating the 1st level boss without triggering the bug. I will open a new issue for this one as his european iso and my japanese iso seem to behave the same.

I had to reload this save state a few times before triggering the coredump

[Former user]

Comment # 11 originally posted by tournier.julien on 2012-07-05T22:40:31.000Z:

and now the coredump

[Former user]

Comment # 12 originally posted by ekeeke31 on 2012-07-05T23:46:05.000Z:

[Former user]

Comment # 13 originally posted by ekeeke31 on 2012-07-06T09:43:25.000Z:

Thanks, the dump confirms what i have seen in win32 port: the emulator crashes while executing a 68k instruction that uses a PC relative offset which points to normally unused memory. Taking care of this kind of access fixed it.

[Former user]

Comment # 14 originally posted by ekeeke31 on 2012-07-15T15:43:37.000Z:

fixed in r693