software intrs

[Chris Torek]

>In article <10346 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
>>on the Vax and the Tahoe, using the Software Interrupt Request
>>Register, SIRR.
 
In article <454 at cosmo.UUCP> jum at cosmo.UUCP (Uwe Mager) writes:
>gee, how do they do that on a 680xx ? setting flags ?

On the Sun-3, at least, there is a hardware register that has a
bit that can be set to cause an interrupt at IPL 1; see
/sys/sun3/locore.s.  Another alternative (one which I in fact
implemented on one 68010 system) is to muck with the kernel stacks
and arrange for an rte to `return' to a lower ipl and a service
routine.  (This is horribly gross, but if you have no hardware....)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris at mimsy.umd.edu	Path:	uunet!mimsy!chris