The Gnome CPU could be
found in an old text book about the concept of CPLD and FPGA
programming. It can't be be bought anymore but I decided to let
it "live" for several reasons:
The structure simple
and can be understood with very little effort.
It presents the most
common instructions and addressing forms.
The VHDL code presents
a good practice in order to write synthesisable code (only
one clocked process)
Its possible to make
enhancement of the instructions-set and the structure
(exercises for students)
The Gnome was intended to
implementation at a CPLD based kit (95108) with 108 F/F's and a
32kbyte external RAM.
In my own implementation is the external RAM replaced with a
"special" designed Memory block (more later)