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Message: 7131

Author: ian.rushforth

Date: 07/08/2017

Subject: Re: Guardian corruption / weird rope bug in UMM

 

> Immediately after the bug has kicked in:
> Invisible vertical (#82B7-#82BE): 3A 00 01 C0 00 99 D3 80 > Colourful worm (#82BF-#82C6):  B3 82 DA D2 44 40 44 EC


Corrupted bytes in the room buffer are highlighted in bold.  Some of those values may have been edited by the time the snapshot was taken, by the enactment of the 'Draw the guardians' routine during the same pass through the Main Loop.  (In the snapshot, the Program Counter has arrived at #89FE later in the Main Loop, the LDIR loop which copies the screen buffer to the display file.)


It is notable that the Trigger code (enacted during the 'Move the guardians' routine) starts at #ECDA, and the values 'EC' and 'DA' are both present in the above.  So the corruption may have occurred at the point when the Trigger which comes after the above guardians in the room's guardian list (the one which turns off the 'DIE MORTAL' lettering guardians) was triggered?


 

 

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