Re: MIPS test-and-set

ncm@zembu.com (Nathan Myers) writes:

> Since the actual instruction sequence is probably lifted from the 
> MIPS manual, it's probably much freer than GPL.  For the paranoid,
> the actual instructions, extracted, are just
> 
>    1:
>      ll   %0,%3
>      bnez %0,2f
>       li  %1,1
>      sc   %1,%2
>      beqz %1,1b
>    2:

But note that the ll instruction is MIPS ISA II, which means that it
is not supported by the R3000, which means that it will not work on
most DECstations.

I don't think there is any way to do a reliable test-and-set sequence
in user mode on an R3000.

Ian