[OpenBIOS] How to pass CIF chain arguments on SPARC64?

Tarl Neustaedter tarl-b2 at tarl.net
Wed Apr 9 02:50:59 CEST 2014

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).

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