murray@minster.york.ac.uk (11/11/88)
Hi,
I've the following rather urgent questions about the transputer
and was wondering if someone can answer them, since the INMOS
datasheets that I have seem not to give the necessary info.
In the occam memory map addresses #9 to #12 (18 decimal) on the
T4 and #9 to #1C (28 decimal) are reserved. What values are stored
in each address?
{ The T800 data-sheet I have shows, in order after the Event `link'
at #08: TPtrLoc0, TPtrLoc1, WdescIntSaveLoc, IptrIntSaveLoc,
AregIntSaveLoc, BregIntSaveLoc, CregIntSaveLoc, STATUSIntSaveLoc,
ErefIntSaveLoc, and then a region marked `Reserved for Extended
Functions'. The TPtrLocs are the tops of the timer queues, the
IntSaveLocs are for dumping low-priority context when a high-
priority process is runnable, and the other stuff is marked
down for block moves and such. I am surprised I knew that, and
I think I rather wish that I didn't. gj }
When the timer ticks (for either clock value) a process MAY become
runnable. If this occurs is it placed on the run queue then, or
when the transputer next performs a process rescheduling? (i.e. is
the clock fully asynchronous or does it only check timer expiry
the transputer is doing process manipulation?)
{ I am reasonably confident that I remember being told the clock
can reschedule processes _during_ the execution of intructions,
which is altogether quite as asynchronous as anyone could want. gj }
Many thanks,
Kevin
----
Kevin Murray, Dept. of Comp. Sci., University of York, York, UK, YO1 5DD
murray@uk.ac.york.minster or ..!uunet!mcvax!ukc!minster!murray