Roland> The idea is that we want to get something aligned to 8 bytes.
Michael> Does & 4 do that?
I think so -- I'd have to check to be sure, but the idea is that if
the offset of ha is 4 mod 8, then we should subtract off 4, and if
it's 0 mod 8, then we should subtract off 0. So "& 4" is right, I think.
- R.