Re: [hatari-devel] Lockup & Sidetracked demos

[Thomas Huth <th.huth@xxxxxxxxx>]

> On 12/6/20 9:47 PM, Eero Tamminen wrote:
>> Sorry, I didn't notice this earlier as it wasn't
>> to hatari-devel (I've now changed my mailing list
>> rules to check also subject line, not just to/cc).
>>
>> On 12/6/20 8:00 PM, Laurent Sallafranque wrote:
>>> You can try to download this program again.
>>>
>>> It looks like the same problem I had with Fun industries demo (it didn't
>>> work with all my versions of hatari, but I was pretty sure it was a
>>> working demo). I've downloaded another version and now it works.
>>
>> I set all my Atari related files as read-only, unless program doesn't work
>> when that's done
>> (GEMDOS HD trace shows file whether files are
>> being opened as writable).
>>
>> That way programs can't accidentally corrupt their
>> files.
>>
>>
>> I also keep the original zip files around so that
>> I can verify files against the original files afterwards.  None of
>> Sidetracked demo files have
>> changed/corrupted.
>>
>>
>> I just noticed that tracing shows following just
>> before it panics:
>> ----------------------------
>> ...
>> XBIOS 0x6D Dsp_ExecProg(0x2BE26, 0x2DD, 0x8001)
>>
>> GEMDOS opcode invoked outside of cartridge space
>>
>> Panic: Illegal Instruction
>> ----------------------------

That likely just means that the program executed garbage in the memory and
then crashed.

You'd need to step through the execution to see where it is exactly going
wrong (e.g. by comparing the run to a working one from HD image), but I'd
assume that it fails already earlier and that the "GEMDOS" opcode was really
just junk in memory that got executed by accident.

 Thomas