Date   : Tue, 13 May 2003 15:34:38 +0100
From   : Richard_Talbot-Watkins@...
Subject: Re: BeebEm bugs (was: Compiling Beebem)

Steve Fewell wrote:

> What is wrong with the 6522 timer emulation? Is the timing just out, or
> does it hang as per the FE6E problem that I'm getting?

No, the timing is just out, and almost certainly won't handle 'difficult'
cases like ROL &FE45 or whatever correctly, even if it appears to make a
good job of straightforward (via LDA or whatever) access.

The hang you describe is curious (I seem to remember &A0 being an enable
for timer 1 - is that right?).  You've set up the Auxillary Control
Register (&FE6B?) appropriately, so it's not trying to use some bizarre
timer mode that's maybe not properly implemented?  Since the equivalent
System VIA emulation (&FE4E register) seems to work ok, I'm very
surprised...

Rich
--
                                                                           
 Rich Talbot-Watkins                       Richard_Talbot-Watkins@...      
 Sony Computer Entertainment Europe              Direct line: 01223 341865 
 Cambridge Studio                                                          
                                                                           







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