VIA6522 bugs details

From: Groepaz <>
Date: Fri, 27 Jun 2014 19:56:41 +0200
Message-Id: <>
howdy hackers!

as some (or even most) of you probably know, there are some bugs in the VIA, 
most prominent being the infamous shift-register bug. in another attempt to 
improve emulation, i have started to research and collect related information 
- and was surprised that so little detail info exists. what i have found so 
far is here: (not much as you can see). i am most 
interested in:

- what bugs do you know about other than the ones listed?
- what exactly is the bug?
- how does the bug show when writing software, and what is/was the proposed 
workaround? (this may give some more hints when other info is not available)

as always, whatever comes out of it will be collected and made public in the 
VICE testprograms repository (and then, hopefully, fixed in VICE too of course 


IBM is not a necessary evil. IBM is not necessary. 
<Ted Nelson>

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Received on 2014-06-27 18:00:02

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