I would like to write an interrupt to read scan codes on port 60h (through 25h function of the 21h interrupt) but I don't know well the interrupts structure.
I know that I must PUSH registers (flags managed by IRET?) and POP them before quitting with IRET.
Are there other conditions to be respected?
I saw also that I must OUT 20h to the interrupt controller at 0020h:
I don't understand why.
I may be presomptuous, but any help would be wellcome.