x86 is Turing-complete with no instructions, too: https://github.com/jbangert/trapcc
fwiw, linked to from the article:
> As others have shown, we can compute using alphanumeric machine code[1] or English sentences[2], using only the mov instruction[3], or using the MMU[4] as it handles a never-ending double-fault. Here is my contribution to this genre of Turing tarpit: x86 is Turing-complete with no registers.
[1] http://www.phrack.org/issues.html?issue=57&id=15#article
[2] http://www.cs.jhu.edu/~sam/ccs243-mason.pdf