Re: BBR/BBS 65C02 instruction cycle counts

From: Segher Boessenkool <>
Date: Wed, 29 Jun 2016 17:28:22 -0500
Message-ID: <>
On Wed, Jun 29, 2016 at 09:09:26PM +0100, smf wrote:
> It's much more likely to always be 5. Rockwell say it's 5 on one page 
> and imply it's 5/6/7 on another, so one page is definitely wrong as they 
> disagree & the 5/6/7 doesn't make sense. If you go for 4/5/6 then you're 
> assuming that both pages are wrong. Which is possible, but much less 
> likely than them putting an ** on one page when it wasn't meant to be there.

4/5/6 does make sense with the cycle descriptions though; or, if it is
constant time (which I seriously doubt), 4 always.

> Unless you get hold of some hardware to verify it, or some software that 
> is sensitive to timing that has been developed on real hardware then 
> it's actually not that important.


> More important is the 65ce02, where the instructions take less clock 
> cycles as it's the basis for the commodore 65. I don't think commodore 
> used 65c02 in anything.

4510...  Not so certain that is the same as 65CE02.


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Received on 2016-06-29 23:00:07

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