[A83] Re: Quick quistion about djnz
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[A83] Re: Quick quistion about djnz
----- Original Message -----
From: "Ronald Teune" <rtwolf@gmx.net>
To: <assembly-83@lists.ticalc.org>
Sent: Saturday, November 17, 2001 2:15 PM
Subject: [A83] Re: Quick quistion about djnz
>
> >> >well in a way, all of these instructions aren't stored in ram.
> >> >
> >> >if it was stored in ram we would have a much larger area to work
> >>with(well,
> >> >83+ and the se have ram, but they wouldn't be running from ram). they
> >>are
> >> >already on the chips memory. so it's only the instruction execution
> that
> >> >takes any time, not loading it.
> >
> >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 ....
the chip sets certain 'lines'(as Ronald Teune said) high (logic 1) which
tells what memory address to be at... the byte is just stored as open or
closed gates (logic) and therefore the transfer from that depends only on
the speed of electricity, and the time it takes the CPU to switch to the
next memory address if it's a two byte opcode... and as far as I know it
pretty fast.... enought to be faster that the individual transistors (that
make up logic gate) can switch state :) which make the whole thing...
work... :)
uhm... the last part seems a little confusing but I can understand it.. so
maybe you can too (come on ... just a little effort)...
-Nicolas Gilles
> > SUCKER
> >
> >>
> >>I think 'loading' wouldn't take time at all.
> >>The instructions are probably somewhere on the chip with some address
> >>lines,
> >>and all you have to do is change the address lines, and you have it in
the
> >>blink of an eye, unlike a harddisk.
> >>
> >>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
> >>=================================
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> >>A hen is an eggs way to make a new egg.
> >>
> >>
> >>
> >
> >
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