Date   : Mon, 01 Apr 1996 21:21:14 +0100 (BST)
From   : Tom Seddon <T.W.Seddon@...>
Subject: Re: More VIA queries

On Mon, 1 Apr 1996, James Fidell wrote:

> Tom Seddon wrote:
> 
> The number of clock cycles varies depending on the type of instruction
> and the instruction mode.  The best discussion I've seen of this is
> in the 64doc file which comes with one of the c64 emulators.  It's also
> in the doc directory in the Xbeeb sources.

Hmm, I'll give this idea a miss then -- it seems rather complicated to me!

> Remember that you not only have to handle the variable number of
> cycles before the physical read, but also multiple reads due to
> carry propagation in address calculations within the 6502 and also
> clock-stretching whilst accessing the memory-mapped IO pages.

I know about the multiple reads, but how does the clock stretching affect 
things? I still have problems with about 25% of the games in my 
collection, and I'd like to sort them out.

--Tom
 
    |     ** Tom Seddon **	  E-mail: T.W.Seddon@...
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