64bit data 128Bit address...Re: Building a Z-80 (64bit!!!)

From: Arfon Gryffydd <ArfonRG_at_DIEspammerSCUM.Texas.Net>
Date: Thu Oct 22 14:17:15 1998

First of all, thanks Allison for bring up the technical limitations. Keep
them comming.

As for a 64Bit data bus, there is no reason for a 64bit instruction but,
but with 64bits of data, you can do a hell-of-alot with video and signal
synthesis (i.e. sound).

Now Hans said:

>And now tell me where you need 128 Bit address ? Just in
>case, even to fill a 64 Bit memory you need 4 GIG of
>mem thats just 4 grand ... and 128 Bit memory used ...
>oh unly 16,000,000,000,000 Dollar ... gee rich man

It is good design in my opinion to have your address bus twice as wide as
your data bus. If you keep thinking like "you'll need $16,000,000,000.00
in memory for that address size" you'll do the same stupid thing as:
Micro$oft ("640K is more than enough for anyone"), old programmers ("year
2000 is 20 years away. This stuff will be obsolete by then"), and let us
not forget Intel with their screwy memory addressing schemes on their
pre-X386s. Think ahead! It wouldn't cost that much more or requrie much
more effort to add a few bits to the address bus.

Wow, I didn't intend for that to sound as sarcastic... No offence intended
Hans.

As for the suggestion of using a DEC alpha to emulate a Z-80... I thought
about it but, those darned Alphas are way too expensive for us hobbist.

Tell me more... what are Verilog, Xilinx or Altera?

Anyone know if Zilog is going to beef up the Zx80 line????


Arfon

"Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
bigger and better idiots. So far, the Universe is winning." -- Rich Cook
Received on Thu Oct 22 1998 - 14:17:15 BST