> The other option is to implement TAS as a syscall on mips (as at
> least Ultrix does).  I put in a half-hearted attempt in the past
> to make a generic MI atomic interface - maybe the ``solution'' for
> now is a MIPS-only sysarch() call...

if you could turn off interrupts, you could do something like:

slti $s1, $s0, 1
add $s0, $zero, 1

That'll do TAS on $s0 with the result in $s1 (1 for success, 0 for fail)...
though, I'm sure something like this would have been done if it was so
simple.

I'm a bit wet behind the ears with MIPS, so you can feel free to tell me
that I'm a total idiot. =P

/Andrew