PowerPC64 TLS ABI
Sat Jan 18 01:53:00 GMT 2003
Alan Modra writes:
> Yeah, I suppose. lbzx, lhzx, lwzx, ldx, lhax, lwax, and the update
> forms too.
And the corresponding stores? In fact I think the instructions are
regular enough that it won't be a big problem, but I'll take a look at
the details if you like.
> > Oh, another question. Why variant II data structures?
> > I happen to think they're not as conceptually clean as
> > variant I, and there's no reason to adopt them for a
> > target not trying to be compatible with Sun.
> My original reason for choosing type II was to make use of "the thread
> pointer points to a Thread Control Block of unspecified size and
> content", and actually offset tp from the TCB base in order to
> maximize the useful range of one-instruction tprel addressing. I then
> decided not to bother with an offset tp. I suppose there's really no
> reason we couldn't use an offset tp with variant I, and what's more,
> the offset would be the same as for dtv. ie. r13 - 0x8000 would point
> at TCB. I like it!
But the linker still needs to know the size of the TCB in this scheme,
no? Is that potentially a problem?
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