Recently I created a portable assembler, which made the task of creating assemblers for a CPU really easy. So after tinkering for a bit, I had the idea to create a simple CPU to prove the functionality of my new assembler. So I started creating a simple CPU on Logisim. The CPU has no more than 12 instructions, but its more than enough to run simple programs. The CPU took about an hour to make and the assembler backend took me about 20 minutes to write.
Here on the images, you can see it running Hello World on a loop.