Back in high school, I began to consider designing a new CPU. At that time, the
larger computer systems were 16-bit but I was mostly familiar with the Intel 8-bit CPUs.
As a consequence, I considered both 1) how would one design a fast CPU, and 2) what
would be an effective instruction set. Thus, I designed a 32-bit CPU that ran off of
a microcode engine. In college, I designed and drafted most of the electronics for what I called the
Gigabyte CPU (due to being able to address 4 Gbs of memory). I also wrote the microcode
for the instruction set. Unfortunately, I couldn't build the hardware at the time
due to being a poor college student (the ECL register set itself cost nearly $1,000).
But, being a software engineer, I could write an emulator for the CPU, which I did in
DEC BASIC. Many years passed where life was too busy for me to move the project much
further. Eventually I built the Computer Emulation Framework which
provided the user interface, memory support, and so forth, needed for a Gigabyte CPU emulator.
I updated the microcode, tested it, and wrote
the Gigabyte microcode engine emulator.
The microcode source is included with the CEF32 download, but is also available here.