Re: How interrupts work (x86 vs. C64)

Bjarni Juliusson wrote:
Some time ago I used interrupts at Commodore C-64. When I preset address
of system interrupt (as I know there was only one interrupt available)
to my code (which ended with jump to original address of interrupt) the
result was, that my code was repeated continuously (~60 times pre
second, in other 'thread'). The interrupts at x86 seem to work
differently. How do they work, and how to 'emulate' behavior of
interrupt from C64 ?

There is a table in memory with pointers to a number of interrupt routines to be called when the different interrupts occur. In real mode, this table is at address 0, but in protected mode it can be located anywhere and you set a register pointing to it.

I've read that (but not tried to) even in real mode you can have the IVT anywhere in memory by setting its address using LIDT, just as in PMode...

JJ

.

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