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I have seen a few obscure references to the OPIC on the wiki, thus I did some deep digging, and oh boy, it was fun.

I have written a WIP article on the wiki here: https://wiki.osdev.org/OPIC

All the official documentation on the OPIC has been impressively, completely purged from the Internet, which seems to be a rare feat nowadays.

The OPIC is relevant because it was implemented in late 90s/early 2000s AMD systems, before AMD eventually licensed the APIC from Intel.

The Linux kernel header, openpic.h, has a reference to the "documentation" that has since been taken down. All web archives of the documentation is invalid.

superfrink.net, which contains information about the 8259 PIC that it seems this wiki sourced from, contains an "I don't know" clause about the OPIC at the bottom of the page.

Most information I've gotten about the OPIC has come from a single Stack Overflow question and a few namedrops in some public patents.

Does anyone have some information about the OPIC? It would be nice if you could chip in. Any good information is extremely valuable.

I will be contacting AMD in an effort to obtain more documentation.

rizxt wrote:The OPIC is relevant because it was implemented in late 90s/early 2000s AMD systems, before AMD eventually licensed the APIC from Intel.

Was it ever implemented in x86 systems? I can't find any evidence that it was.

QEMU has references to datasheets for some OpenPIC implementations, but they're mostly PowerPC. (Funny enough, it looks like Intel used OpenPIC for some of their ARM chips.)

If AMD happens to archive their datasheets by publication number, it'll probably be number 19725.

Octocontrabass wrote:If AMD happens to archive their datasheets by publication number, it'll probably be number 19725.

http://www.amd.com/html/products/pcd/openpic/19725c.pdf is where the datasheet used to reside.