27 Oct
2010
27 Oct
'10
2:26 p.m.
________________________________
From: Tony Duell <ard at p850ug1.demon.co.uk>
As an aside. I've worked on a machine with an 8-bit microcode address that was
normally written as 4 octal digits. The address was split into 2 nybbles (this
makes a lot of sense based ont he procressor design) and each nyble was writen
as as octal number from 00 to 17. So the highest address was written as 1717.
[It's the HP9800 CPU if anyone's curious...]
I'm interested. Those are great little machines. I think it would be really
interesting to put that CPU in an FPGA. Are there some documents describing the
architecture and the microcode?
Dave