The Elementary Microprocessor is a completely functional 16-bit accumulator architecture CPU simulated in the Logisim program. Logisim is a a free Java logic simulation program available on every major platform.You can write programs in the EM's assembly language, load them into the simulator, run them on the processor, and interact with it as a user. The EM is intended as an educational resource for those of us who are interested in learning not just what a CPU does, but exactly how a CPU works but who aren't about to go spend 2 years in college learning how to do it from scratch.