IDT and PIC question

[neowert]

When you go into pmode, do you need to remap the PIC to int 32 and above because there are more cpu exceptions in pmode than real mode?

[Curufir]

Yes, the exceptions/reserved interrupts are at 0->31 the initial mapping of the PIC is within this range, so they clash.

It's not obligatory to remap the PICs, but it saves having to figure out wether an exception has occurred or it was just a normal interrupt. You have 256 interrupts at your disposal so remapping to leave the exceptions the first 32 and the IRQs somewhere else is not a big loss.

Curufir

[Tom]

I've noticed that sometimes the CPU tripple faults when you DON'T remap the IRQs...at least with the IDT I had.