The PPC32 backend currently supports more-or-less any function that manipulates only integers and does not call other functions or use exceptions. There are a bunch of things which could be done: The register allocator is currently exceedingly stupid. Writing another one would be a good idea, but this is pretty much independent from anything else in pypy. On a similar note support for floats shouldn't be too hard. Would require support for float registers, etc. Again thoroughly independent. Local exceptions (i.e. ones that do not escape from the function, e.g. overflow errors) would be an interesting thing to support. There is no support at all for PBCs, and this is a huge topic that is a large part of what the LLInterpreter group is worrying about. There is probably not much point in doing any of these things at this sprint.