Comment by emily-c

I am talking about the platform more than the ISA. Some interesting resources:

https://sites.google.com/site/pinczakko/system-address-map-i...

https://www.youtube.com/playlist?list=PLBTQvUDSl81dTG_5Uk2my...

http://xillybus.com/tutorials/pci-express-tlp-pcie-primer-tu...

http://xillybus.com/tutorials/pci-express-tlp-pcie-primer-tu...

https://www.amazon.com/Quick-Boot-Pete-Dice/dp/1501515381/

https://opensecuritytraining.info/IntroBIOS.html

https://acpica.org/sites/acpica/files/asl_tutorial_v20190625...

And of course the MindShare books.