I've been distracted from my 4-bit processor ever since I saw a 1-bit processor concept on the Hack-a-day website.
It's just more R&D for my own CPU experiments but it has definitely taken a little of my time away from the 4-bit processor I started back in January. At first I wasn't even sure that it was a 1-bit processor because each instruction consists of a 1-bit operator and two 4-bit operands but then as I considered it more, I realized that it truely is a 1-bit CPU and then I started wondering how I would make it with standard TTL technology. I even built a Javacript version of it to investigate further.
The single instruction is: COPY, BRANCH IF X, meaning that for each line in the program the instruction is copied to the address in the first operand. If the instruction copied = 1, then the program will branch to the address in the second operand.