Re: mips RDHWR instruction in glibc

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

On Wed, 14 Jun 2006 12:50:40 -0400, Daniel Jacobowitz <dan@debian.org> wrote:
> > For example, in the code below, RDHWR is placed _before_ checking the
> > error.  I suppose these instructions were reordered by gcc's
> > optimization, but the optimization would have large negative effect in
> > this case.
> 
> You'd have to figure out how to get GCC not to eagerly schedule the
> rdhwr.  This might be quite hard.  I don't know much about this part of
> the scheduler.

I really did not understand yet how errno is bound TLS.  I found some
"rdhwr" in glibc-ports source code (tls-macros.h, nptl/tls.h).  The
RDHWR instruction in the example code comes from one of them, no?

I also found a "rdhwr" in gcc's mips.md file ("tls_get_tp_<mode>").
Is this the origin?  MD is a very foreign language for me...

---
Atsushi Nemoto