Either that, or a compiler with such an instruction set as the target.
For instance:
https://github.com/arthaud/c2bf
It seems like this is a frivolous subject, but it is actually quite enlightening to realize just how little is required to get something that computes, it changes how you view the whole concept of computation.
Someone wrote a C compiler that generates code using only x86 MOV instructs.
It seems to program with such a reduced instruction set requires one to be either a genius or a computer (i.e. generated code). I'm neither :(