Re: 264 kernals, bugs, ntsc hack, etc.

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Tue, 06 Sep 2011 17:19:49 +0200 Message-ID: <4E663A15.5000606@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 09/06/2011 06:57 AM, William Levak wrote:
>> Hm... So the problem is that $79 contains something non-zero at the
>> wrong moment. Is it possible to prevent the bug from causing problems
>> if the first command after exiting the monitor is 'CLR'? It does write
>> a zero to $79. Or does 'CLR' also trigger the bug?
>
> One byte op codes do not change $79-. If you had "30 30" at $7A-7B, it
> remains there.
>
> The safe thing would be to zero out $79-7B before exiting.

The other email mentioned that the bug is only triggered if $79 is not 
zero. CLR writes a zero to $79, so that should solve the problem unless 
CLR also triggers the bug before clearing $79. If this is the case then 
the only save way would be zeroing $79-7B, yes.

  Gerrit

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