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IRQ - INT, what's the difference?

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Spike

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Dec 7, 1998, 3:00:00 AM12/7/98
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HI!

What's the difference between INT and IRQ?

SPIKE


Peter Remmers

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Dec 7, 1998, 3:00:00 AM12/7/98
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>What's the difference between INT and IRQ?


IRQs are hardware interrupts. They are from 0 to 7 on
the first controller and from 8 to 15 on the second.

INTs are software interrupts. They range from 0 to 255.
Most of them are generated by software with the INT
CPU instruction to call BIOS or DOS services.
The IRQs are mapped to software INT levels:
IRQ 0..7 = INT 8..0Fh and IRQ 8..15 = INT 70h..77h.
However this mapping can be reprogrammed in protected
(or V86?) mode.

Peter Remmers


fe20m...@uni-lj.si

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Dec 12, 1998, 3:00:00 AM12/12/98
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IRQ stands for Interrupt Request - it's a way of telling apart
hardware interrupts. Different devices can use different IRQ
numbers. Original 8086 and 80286 processors
have no direct means to differentiate between hardware interrupts
(except NMI). The Interrupt Controller chip takes care of that with
its IRQ numbering system - at least according to my knowledge. (please
someone correct me if I'm wrong!)


--

/\/\atjaz |<ovac
FRI LJ


On 7 Dec 1998, Spike wrote:

> HI!


>
> What's the difference between INT and IRQ?
>

> SPIKE
>
>
>


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