Re: thread-ready ABIs

[Daniel Jacobowitz <dan@debian.org>]

On Fri, Jan 18, 2002 at 10:19:08AM -0800, H . J . Lu wrote:
> > MIPS: Who feels responsible?  Andreas, HJ?
> > 
> 
> I don't see there are any registers we can use without breaking ABI.
> On the other hand, can we change the mips kernel to save k0 or k1 for
> user space?

No, there are no free registers and $k0/$k1 are needed by the kernel
for exceptions.  The only way I can see to do this would be to change
the ABI.

There are none available; the least used that I see is $v1, but $v1 is
used to return half of a double precision return value.  We would have
to steal one of the existing call-saved or call-clobbered registers.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer