On 2014-Apr-8, 01:25 , Mark Cave-Ayland wrote:
[...] I appreciate that the document referenced above is actually for a 32-bit SPARC ISA, however the indication is that something similar was in place for 64-bit SPARC.
Not that I know of. I've been on the road for the past week, haven't had a chance to go looking. But two things: 1) I'll be surprised if I find a 64-bit version of chain documentation at Oracle. 2) If I do, I'd expect it to use the same registers. I wouldn't expect a change from the use of %o0-04 just because the register size changed.
The only thing I can think that's even remotely associated with such register use is how Openboot itself is started, with arguments in registers from the Hypervisor for sun4v.
More amusingly is that the last few NetBSD releases simply call the kernel entry point directly rather than bothering to invoke "chain" via the CIF at all.
Probably because Chain didn't work. Don't know when it was commented out, but was well over a decade ago. Possibly in the 32- to 64-bit transition (sun4m to sun4u).