Re: A85: **RIGEL - the NEW shell**
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Re: A85: **RIGEL - the NEW shell**
Ben Sferrazza wrote:
> Will Stokes wrote:
> >
> > what is "daisy-chained interrupt" support?
> It is essentially mutilple interrupt support. So when you install
> an
> interrupt it creates "a chain" to whatever interrupts are currently
> installed. You can install a grayscale interrupt handler and then
> install a sound interrupt handler. They are in essence "chained"
> together, as one is called right after the other when an interrupt
> occurs.
Well... actually, I think daisy-chained interrupts are the kind that PCs
use: There is an interrupt vector in memory somewhere, and when a
program tries to install a new interrupt, it rembers the old address and
changes the address to its own interrupt handler. Then it makes sure it
jumps to the address of the old interrupt handlers when it's done. It's
"daisy-chained" because it's sorta like a link list. It's easy to
"insert" a new interrupt into the chain. (Usgard uses something a bit
different -- it's just a normal list of calls which is manipulated by
the INT_ functions.)
Sam
--
Sam Davies <sdavies@mail.trilogy.net>
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