Processors like this require support circuitry (memory, io, clocks, etc) to do much of anything useful. I don't think there is enough gpio on the Pi to emulate all that. By the time you have all the of support stuff, you've got a motherboard, and by the time you've got that, you might as well have a full up computer. Even an older, simpler processor, like a Z80 or a 6502 (all the retro rage right now) would need more than the Pi gpio. Although hooking up a Pi to a full up computer wouldn't be bad, I don't think it would be entertaining for long. Or, at least it wouldn't be as interesting as hooking up to a micro-controller, like an AVR (Arduino), and the micro-controller doesn't need nearly as much support circuitry. Get the whole setup for less than $30.