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  • Joined: 14 Jan 2012
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Problem with Bubble Bobble ROM
Post Posted: Sat Jan 14, 2012 12:13 am
Hi all,

I'm hoping I am posting in the right section. I've tried Googling this however can find no results.

First of all, I love MEKA. Only discovered it last night (I have been using Dega for years, however I've recently accquired a PC gamepad and needed an emulator with which I could configure the buttons).

On Bubble Bobble (EU).sms ROM I can get to Level 11 however it will then "lock up" and not go past that stage. It is the whole game that locks up (sound as well as gameplay). I can exit fullscreen of MEKA and re-load a ROM, etc.

I have been thrashing my Sega ROMS since getting this last night and no other games have issues. Any idea of a fix? Thanks in advance.

Carrion
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Post Posted: Sat Jan 14, 2012 1:52 am
OK, one thing to note is that MEKA isn't a very accurate SMS emulator (sorry Bock) - the Z80 core is balls-accurate, but the VDP has plenty of things that can be fixed easily (assuming it's not as messy as libmodplug), and should.

Are you sure the ROM is good? There are tools out there which can check the "TMR SEGA" checksum.

With that said, turn on the MEKA debugger, and try to pin down roughly where it crashes. A save state would be good, too.
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Post Posted: Sat Jan 14, 2012 2:03 am
I recall the same bug has been reported years ago, I assumed it was fixed but apparently not. If you have a savestate of the level before the crash it would be helpful.

Out of curiosity are you running in PAL/SECAM emulation mode, not NTSC?

As mentionned indeed MEKA is not the most accurate emulator nowadays, but I'll do my best to fix it whenever possible.
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Post Posted: Sat Jan 14, 2012 3:21 am
Bock wrote
I recall the same bug has been reported years ago, I assumed it was fixed but apparently not. If you have a savestate of the level before the crash it would be helpful.

Out of curiosity are you running in PAL/SECAM emulation mode, not NTSC?

As mentionned indeed MEKA is not the most accurate emulator nowadays, but I'll do my best to fix it whenever possible.


Thanks for the replies.

I was running it in PAL/SECAM emulation mode, not NTSC. I will get a savestate of the level just before the crash for you.

Do I upload the file to here? I am not overly sure sorry.

I do not have any experience with working with debuggers so I do not think I would be able to pinpoint the problem myself.

Thanks again.
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Post Posted: Sat Jan 14, 2012 3:40 am
If you ZIP the savestat you can add it to any message here as attachment. Thanks for your help!
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Post Posted: Sun Sep 29, 2013 11:34 am
Last edited by RetroSpark on Sun Sep 29, 2013 3:03 pm; edited 1 time in total
I have recently had SMS Bubble Bobble "lock up" in MEKA as well. It seems to get stuck in a loop waiting (with interrupts disabled) for a certain pattern in the lower bits of the R register.

Perhaps the R register emulation in MEKA is not sufficiently accurate?

Edit: Interestingly, this loop was changed for the GG version. The changes include the removal of the R register access and the addition of NOPs to keep the code size the same.
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Post Posted: Sun Sep 29, 2013 2:21 pm
Have you got a savestate or a program location to examine?
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Post Posted: Sun Sep 29, 2013 3:30 pm
Savestate attached. PC should be at $9f57 (ROM $0df57) - the "LD A,R" instruction at the top of the loop.

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Post Posted: Mon Apr 06, 2015 9:32 am
Better later than never, this is fixed since the Meka 0.8x 2015-05-01 build:
http://www.smspower.org/forums/13019-Meka080?start=300#86093
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