BIOS PIT/PIC/A20/Memory

[mr. xsism]

hello all,
i am looking for specs or explanations on how to detect PIC and PIT chip types and how to enable the A20 bit with BIOS. The memory part is covered. But i don't know of any other ints for the aforementioned. Does someone know what they are? Iy is VITAL, but it would be nice to verify the hardware for my project. Thank you in adv.

Regards,
mr. xsism

[Tim]

You can assume the presence of a standard PIC and PIT in all PCs. A PC without a PIC or PIT is like a PC without a CPU.

You can detect an APIC and IOAPIC by parsing the SMP configuration table located within BIOS memory.

[mr. xsism]

Alright, that sounds great. What about the A20 gate enabling. Isn't there a standard BIOS interrupt i can call to init it, instead of guessing with port io?

Thanks tim.

Regards,
mr. xsism

[Tim]

I believe there are several, but I'm the wrong person to ask, since I let GRUB take care of all this.