interrupt priority

[garnsworthy]

I was wondering if anyone could point me in the right area to look for a
list of external interupts and their priority. ie. where is the interupt
vector loaded up?

I found the cpu(?) interupts in head.S, but I am interested in the
(pci/dma/sound/ethernet) interupts.

Thanks,
chris

[waldo frinkazoid]

strange question ....

interupts and their priority

In total there are 16 interupts (hardware) but you lose one of them because
IRQ's are working in cascade==>
first there were only 8 interupts bt as most people ran out of interupts
they added another 8 .. and "installed' them on top of interupt 2 ==>

8 9 10 11 12 13 14 15
---------------------------------------
|
0 1 2 3 4 5 6 7

as you can make out from the drawing the priority of interupts is ==>
0 1 2 8 9 10 11 12 13 14 15 3 4 5
6 7

kind of and odd way to count but it's true

so ... no the distribution if IRQ's
in PnP (Plug and Pray) systems teh distributions of irq's is handeled by the
bios and the os
there are a few irq's that cant be changed =>
0 system clock
1 keyboard
8 realtime clock
13 FPU floating point unit
and then there are irq's that are used most of the time by some devices but
can be shared and so on ==>
3 com2
4 com1
5 soundcard
6 floppy controller
7 lpt1
9 xxxxx
10 xxxxx
11 xxxxx
12 ps/2 mouse
14 IDE1
15 IDE2

then there is this ... "I found the cpu(?) interupts in head" what do you
mean ?
as an IRQ interupts the processor ==> why would the processor interupt the
processor ?

Best Regards
waldo

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