[A83] Re: Quick quistion about djnz
[Prev][Next][Index][Thread]
[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.
Why doesn't z80 do it? Or is it too complex?
>///Olle
Groeten,
Ronald Teune
Using Opera since 08/10/2001
http://www.zeekoe.cjb.net
http://cloud.prohosting.com/zeekoe *NEW* (English)
iets@zeekoe.cjb.net
=================================
Anything that is good and useful is made of chocolate.
A hen is an eggs way to make a new egg.