[A83] Re: Quick quistion about djnz
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[A83] Re: Quick quistion about djnz
At 22:27 2001-11-17, you wrote:
> > >hmmmm, everybody gets it the wrong way. I mean the transfer
> > >of the instruction from 9327h to the istruction register,
> > >if there is such a register. And where the instruction
> > >is decoded.
> >
> > Why do you have to transfer it? It's just a byte, and probably points to a
> > location in the z80 or something
> >
>
>Well I'm not sure how exactly it works.. but I think it works kind of like a
>multiplexer/demultiplexer + a bunch of State holders ....
Yes, it has to be loaded into the processor from the memory, but this is,
as earlier said, calculated into the t-states.
Ever noticed that there is no instructions less then 4 t-states?
Other processors like the 68k prefetch instructions, that is, while it
executes one instruction, it fetches the next from memory.
///Olle
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