Could you also allow the regular "timebase-frequency" property
to consist of two cells, with the same semantics?  That's what
some other systems do.  Hey, it'd simplify this code, if anything :-)

In fact, some kernel code already does this if I'm not mistaken
(the Cell port, perhaps?)

Yeah it seems reasonable to just use the property size, I'll submit an
incremental patch for that.

Anton