Date   : Tue, 03 Apr 2001 20:13:15 +0100 (BST)
From   : jim <jim@...>
Subject: Re: 6502 Technical Term

> > Just quickly, I'm (attempting) fixing instruction timing in BeebEm, but I
> > can't quite work out what "Add 1 cycle if page boundary crossed means".
> 
> The extra cycle is the high-byte address fixup needed if the calculated
> address is in a different page from the base address, i.e. adding the
> offset crosses a page boundary.

Bad form to reply to one's own messages, I know, but I just thought that a
better way of putting it might be that "page boundary crossed" means
"carry occurs from low to high address byte during index calculation". 

jim
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