On Sat, Apr 07, 2001 at 12:55:24PM +0200, Maciej W. Rozycki wrote:
>
> You are right, of course. That's why glibc contains two versions of
> _test_and_set() code. If compiled for MIPS I, glibc uses a syscall
> (currently sysmips()), while for MIPS II and higher it uses inline
> assembly code which makes use of LL/SC.
>
> That's exactly the way glibc does CPU-model-specific code for other
> archs.
The problem is that it is compile time - I would like to have
a runtime version - Just export the existance of ll/sc to
userspace somewhow.
> > I've seen the hybrid proposal of having libc determine the LL/SC
> > capability of the processor and either executing the instructions
> > or doing the syscall as appropriate. While that would allow
> > near-optimal performance on all systems, I find it troublesome,
> > both on the principle that the OS should conceal hardware
> > implementation details from the user, and on the practical basis
> > that glibc is the last place I would want to put more CPU-specific
> > cruft. But reasonable people can disagree.
>
> I don't like run-time detection either. The compile-time choice is
> sufficient enough. The _test_and_set() library function already hides
> implementation details from the user.
It isnt sufficent as we need a glibc beeing able to run on old
decstations AND on newer machines like the Lasat machine
which has an R5000.
Flo
--
Florian Lohoff flo@rfc822.org +49-5201-669912
Why is it called "common sense" when nobody seems to have any?
