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Hi,

Can someone tell me what:

__PHYSICAL_MEMORY_EXTENSION__

Does in the APIC example code? Is that the same as PAE? And why would the APIC care about that?

Thanks,

Scott Franco

In the provided example code, the system is assumed to be in 32-bit mode with a 32-bit address bus. That code checks if the system is using PAE paging, thus a 36-bit address bus. If so, it supports relocating the local APIC to addresses to higher memory locations than 4 GB, the maximum address on a system with a 32-bit address bus.
P.S:

Beginner Mistakes wrote:This may look like a set of tutorials to copy & paste, plus a forum to ask your questions whenever you get stuck. This is not so.