How to catch interrupt
bde at zeta.org.au
Wed Jun 16 22:20:26 GMT 2004
On Wed, 16 Jun 2004, Roman Kurakin wrote:
> How to catch interrupt for ISA device before registering handler for it?
This cannot be done without duplicating lots of interrupt handler
registration code. (Actually only a little for a quick MD hack: just
setidt() to point to an interrupt handler, plus enabling the ICU^WPIC,
plus changing the normal code to not un-enable the PIC. npx.c still
does something like this in RELENG_4.)
However, you may only need to test for pending interrupts. This can
be done for isa interrupts using isa_irq_pending() to get a bitmap of
pending irqs. See sio.c. On i386's there are also some newer harder
to use even less portable interfaces for determining pending irqs.
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