[btilly]

All loops and branching logic has to ultimately come down to machine language instructions that your computer chip interprets as conditional, if this do that.

To get an example of what can be done at the lowest level, see http://zsmith.co/intel.html for the instructions that a Pentium chip accepts. In particular look at http://zsmith.co/intel_j.html and http://zsmith.co/intel_l.html#loop.