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Nibbler crashing


Level42
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Through the attention that the arcade game got lately (WR etc.) I found the Atari version but....mine always seems to crash after a certain level.

 

Is my copy (downloaded) bad or does it require a certain OS ?

 

Pretty good conversion !

Edited by Level42
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Through the attention that the arcade game got lately (WR etc.) I found the Atari version but....mine always seems to crash after a certain level.

 

Is my copy (downloaded) bad or does it require a certain OS ?

 

Pretty good conversion !

 

Hi!

 

My daughter and I used to play nibbler quite a lot. We did run in the same issue. Strange enough another game, which is quite the same, called COBRARACE has exact the same issue, and does crash too from time to time. It's pretty odd. Both the XEX and the ATR file of Nibbler do crash here. I also tried OS B and Rev. 2 XL/XE os, but same issue. It's probably not related to the OS. It looks to me like a DLI crash. But I'm not sure.

 

It's a pity, since Nibbler is quite a great game. It will always have a special place in my heart (oh my god, this sounds a little bit too much dramatically) ... but it's true. It was the first real game my daughter was able to play with a joystick on atari 8bit. Now she is better in controlling the joystick. Now she is 6 years old (almost 7) she plays frogger, frogger 2, Pac Man Arcade version (which is the BEST Pac Man port for atari 8bit when I may believe her!!!), Millipede, MegaMania, International Karate Championship, Parachute, Dynakillers and some MultiJoy games. Although It's still easy for me to win from her, I notice a lot of improvement every time we play the Atari. It's so much fun!

 

But back to the topic: I wished someone could fix nibbler and/or cobrarace...

Problem is, it does not crash on the same spot (well I did not notice so far) and sometimes it does not crash at all... so hard to bugfix.

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Dramatical license granted and extended for as long as needed.

 

While I've played it and really like it, I guess not long enough for it to crash that I can recall. But I'm not a serious gamer by any stretch. Does it just lock up? Or what? Screen goes funny at the same time? A few details please, in other words.

 

Which emulator(s) powersoft?

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I've played the superb Nibbler for a lot of years on real hardware (multiboot and original disk) both crash occasionally at seemingly random times during play often some graphical corruption (original disk ver may be slightly better?)

 

For me Nibbler is one of the best A8 games and loved by all who play it.

 

Interestingly Last time we played in the HSC I did somehow get past the point where the logic got harder and the levels went a bit easier for a period. I guess the programmer never tested that far though it did get harder again.

 

There is another bug where you can nibble yourself (!) at high speeds and cause the game to lock up - if I remember it's when you are on the "dots" screens and approacing your vertical trunk from the sides, probably down to timing of the routines.

 

:)

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  • 2 weeks later...

Thanks for the input, at least now I know it's not my file or OS. It's really too bad as it's such a fun little game.

 

Does anyone know if the C64 version has issues too ?

 

I'd have to play it more to see if I can see any "pattern" to the crashes.

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Well when playing nibbler some times i found out that Atarimax Flashcarts seems best, i remember change setting for loader base adress or the setting for loader local varable space.

 

Can' remember the exact setting now but i did at least one change to one of these settings otherwise Nibbler would crash on startup.

 

So after applying the change in the settings i think the game would run stable as run from the Atarimax Flashcart. At least i think it would be stable.

 

Hmm wonder if i also loaded the Atari 800 OSb also. Sorry really cant remember for the moment.

Edited by BioFreeze
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Well when playing nibbler some times i found out that Atarimax Flashcarts seems best, i remember change setting for loader base adress or the setting for loader local varable space.

 

Can' remember the exact setting now but i did at least one change to one of these settings otherwise Nibbler would crash on startup.

 

So after applying the change in the settings i think the game would run stable as run from the Atarimax Flashcart. At least i think it would be stable.

 

Hmm wonder if i also loaded the Atari 800 OSb also. Sorry really cant remember for the moment.

 

It's not the loader base. If that's an issue, then that is another issue.

 

The disk version also crashes and boots from my 1050 on a Stock Atari 800XL, also tested on Original 48K Atari 800. All same issue.

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Crap, I just bought an original floppy version from eBay in the hope that that might be stable.

 

I did notice another one advertised had a small label "copy with happy" on it so it is clearly protected in some way....so I figured maybe it was cracked poorly or something.....

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I'll test this game further...

 

I think it is a DLI bug where not all registers are put and pulled to/from the stack. In most cases in this game it probably doesn't matter, but at some point it goes wrong. The problems are now:

 

1) Find out whether this theory is right.

 

2) If it is right, to find out which DLI is causing trouble.

 

3) Or if it is not right (step 1) to find out what the real reason is for crashing

 

4) If found then fix.

 

I'll take a look at it soon!

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I'll test this game further...

 

I think it is a DLI bug where not all registers are put and pulled to/from the stack. In most cases in this game it probably doesn't matter, but at some point it goes wrong. The problems are now:

 

1) Find out whether this theory is right.

 

2) If it is right, to find out which DLI is causing trouble.

 

3) Or if it is not right (step 1) to find out what the real reason is for crashing

 

4) If found then fix.

 

I'll take a look at it soon!

That's great :thumbsup: :thumbsup:

... and then perhaps you can see if you can fix the "byte yourself at speed from the side problem": you are moving horizontally dot is in the vertical space your body is the other side of it. I think the kill routine kicks in after the dot has been eaten and removed but before it's checked to level up (happens from level 6 9?? when you move faster). You end up with no dots left on the grid screens no matter how many lives you have left, will confirm this ;)

Edited by therealbountybob
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Caught it in the debugger. It's caused by trying to change the DLI address immediately after disabling the DLI; this fails due to interrupt dispatch latencies and the game crashes because only one byte of VDSLST was changed. It's not NTSC/PAL specific. A NOP in between the writes to NMIEN and VDSLST would probably fix it.

- 28629: 25: 84 | A=04 X=80 Y=00 (    Z ) | 044B: 20 20 18          JSR $1820
  + 28629: 25: 96 | A=04 X=80 Y=00 (    Z ) | 1820: 20 36 0E          JSR $0E36
  + 28629:161: 18 | A=00 X=80 Y=00 (    Z ) | 1823: 20 F5 17          JSR $17F5
    28630: 86:102 | A=98 X=80 Y=28 (    ZC) | 1826: A2 34             LDX #$34
    28630: 86:104 | A=98 X=34 Y=28 (     C) | 1828: A0 05             LDY #$05
  - 28630: 86:106 | A=98 X=34 Y=05 (     C) | 182A: 20 E5 04          JSR $04E5
      28630: 86:112 | A=98 X=34 Y=05 (     C) | 04E5: A9 00             LDA #$00
      28630: 87:  1 | A=00 X=34 Y=05 (    ZC) | 04E7: 8D 0E D4          STA NMIEN
      28630: 87:  9 | A=00 X=34 Y=05 (    ZC) | 04EA: 8E 00 02          STX VDSLST
    - NMI interrupt (DLI)
        28630: 87: 20 | A=00 X=34 Y=05 (   IZC) | C018: 2C 0F D4          BIT NMIST
        28630: 87: 32 | A=00 X=34 Y=05 (N  IZC) | C01B: 10 03             BPL $C020
        28630: 87: 40 | A=00 X=34 Y=05 (N  IZC) | C01D: 6C 00 02          JMP (VDSLST)
        28630: 87: 60 | A=00 X=34 Y=05 (N  IZC) | 0434: 16 A9             ASL $A9,X    ;$DD
        28630: 87: 72 | A=00 X=34 Y=05 (   I  ) | 0436: FF 8D FC          ISB $FC8D,X  ;$FCC1
        28630: 87: 86 | A=FC X=34 Y=05 (N  I  ) | 0439: 02                KIL

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Wow, just wow ! This is awesome stuff !!! A fixed version of a Nibbler would be brilliant !!!!

 

I've played the game on my PAL machines mostly and it indeed crashes there too.

 

I do also have an NTSC machine so I can test both.

 

Thanks for all involved !

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  • 4 weeks later...

Oops forgot about this a bit.....I received the original copy on disk and .....it booted straight up without any problems. The disk is definitely protected. So far it only crashed once in about 10 games, but it did crash....so it must be a bug in the original, not something introduced by cracking it.

 

Anyone got a tip on how to back up this floppy ? I have a Mega-Speedy which can emulate all 1050 upgrades. I guess I could use Happy mode but aren't the Speedy modes also capable of copying protected disks ?

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Yes,

 

the Speedy Systemdisk contains a program named 1) Backup-Copy - you can use it to make backups of your copy-protected disks (but the backups will still be copy-protected like the original). Since Backup-Copy only works with 90k disks and only with easy copy-protections, there is also 2) Ultra-Copier by LDS (U.Petersen) and 3) MS-Copy (1050) available, both should be able to copy 90k and 130k copy-protected disks. While the Backup-Copy program works with Start, Select and Option, the other programs also require to input certain parameters and since I am a bloody amateur I never knew what to input there (allthough I did have original disks with a manual) and thus I could not use Ultra-Copier or MS-Copy in any way...

 

Last not least, for the Speedy there exists a Turbo-Emulator to emulate the Turbo 1050. Load this file (programmed by P.Sabath and E.Reuss) with ultraspeed enabled (e.g. from an ultraspeed DOS or Gamedos) into the Floppy and after a short while, your Speedy is a Turbo 1050. Press Reset and it will do a coldstart, you will now see the Turbo bootmenu appear, there press Option to load the Solid State utilities and then press Select until 4) the Backup machine appears. The backup-machine will also copy your copy-protected 90k disks (will refuse to copy 130k disks) and works much better than the Backup-Copy of the Speedy, but again, the backups will still have copy-protection. With the Backup-machine you have two options to copy your disk, a) simply press Start to copy it and in case the copied disk does not work, then b) load the backup-machine again and press Option (?) to choose "XALIGN" and then press Start to copy the disk, now it should work, otherwise you are out of luck...

 

You can find some of these tools here (Speedy Systemdisk, Speedy Backup, MS-Copy):

http://ftp.pigwa.net/stuff/collections/holmes%20cd/Holmes%201/ATR%20Programs/Applications%20A-Z/index.html

or here:

http://www.atarionline.pl/v01/index.php?ct=utils&sub=6.%20Stacja%20dyskietek&PHPSESSID=6485a9423a9bd08df0c6909daeabce0f

 

Note: The "ultraspeed Backup" which you also find there is for the US-doubler (will not work with Happy or Speedy). And since the Turbo 1050 emulator is not available at both websites, I attach it here... (could not find Ultra-Copy or Ultra-Copier by LDS anywhere).

 

Turbo_Emu.zip

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  • 1 year later...

When I have time I might fix it...

 

But, one other thing, has someone already discovered how to force a crash? It would be very handy to know how to crash the game, so then I know a fix cured the problem or not...

It's very random as far as I have experienced. Would be awesome if you could find some time to fix this ;)

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