[OpenBIOS] Milax and the alarm word

Mark Cave-Ayland mark.cave-ayland at siriusit.co.uk
Wed Dec 9 10:33:27 CET 2009

Tarl Neustaedter wrote:

> I believe either the console or serial driver will do that, and possibly 
> the secondary bootstrapper to cycle the \-/| twirly baton.

Yeah. Checking against the online OpenSolaris source, it looks as if 
it's trying to do the twirly baton. Although interestingly the use of 
alarm seems to have been removed from the latest code browsable online.

>> Does SPARC64 have a way of counting elapsed time (some kind of clock 
>> tick register) so that it would be possible to measure this in the 
>> main loop? 
> Yup. It's usually available through "stick@" - I believe it counts 
> nanoseconds.

Okay. I've had a quick grep through the Qemu sources and I can see that 
there is some mention of a tick command - I'm not quite sure what 
guarantees there are on timing/resolution in the Qemu implementation 
though. Blue, can you offer any advice here?

> Sorry I wasn't able to review your stuff, which looked reasonably 
> correct, but I'm on vacation at the moment.

I was fairly sure it was okay (as forthstrap is used to build itself) 
but wasn't too sure at the time that I had missed anything. However, 
I've performed tests using all of the control flow words with the 
debugger and everything seems to act as I would expect. Plus the Fcode 
evaluator now seems to resolve backwards branches correctly.

TBH I'm really grateful for the advice; it's nice to have someone around 
who knows what the behaviour *should* be as I only have physical access 
to 1 Solaris box, and it's being used to host various services and so I 
can't keep rebooting it all the time!



Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs

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