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Re: thread-ready ABIs
On Mon, Jan 21, 2002 at 10:52:53AM -0800, H . J . Lu wrote:
> On Mon, Jan 21, 2002 at 10:36:26AM -0800, Ulrich Drepper wrote:
> > "H . J . Lu" <hjl@lucon.org> writes:
> >
> > > Ulrich, should applciations have access to thread register directly?
> >
> > It doesn't matter. The value isn't changed in the lifetime of a
> > thread. So the overhead of a syscall wouldn't be too much. And
> > protection against programs overwriting the register isn't necessary.
> > It's the program's fault if that happens.
>
> Thq question is if we should reserve $23 outside of glibc. $23 is
> a saved register in the MIPS ABI. It doesn't change across function
> calls. If applications outside of glibc don't need to access the
> thread register directly, that means $23 can be used as a saved
> register. We don't have to change anything when compiling applications.
> We only need to compile glibc with $23 reserved as the thread register.
In another word, is a thread register purely a convention within glibc
as long as it doesn't change when entering glibc?
H.J.