MEM FEE00000h - Pentium - LOCAL APIC Size: 4096 BYTEs Notes: the Advanced Programmable Interrupt Controller built into multiprocessor-capable Pentiums (P54C, etc. -- basically 75MHz and faster Pentiums) maps its registers into the top of the physical address space on data reads and writes, but not on code reads; data accesses to the APIC registers do not cause external bus cycles the APIC's registers are only visible when the APIC is enabled (which occurs at CPU(Central Processing Unit) The microprocessor which executes programs on your computer. reset when external data lines contain proper signals); all accesses to APIC registers should use 32-bit reads or writes, as 8-bit and 16-bit accesses may produce unpredictable results the PentiumPro (P6) permits the address at which the local APIC appears to be changed with Model-Specific Register 0000001Bh SeeAlso: MEM FEC00000h,MEM FEE00020h,MEM xxxxh:xxx0h"Multiprocessor" SeeAlso: MSR(Model-Specific Register) Additional, indirectly-accessible, registers containing control or status information about various aspects of the processor such as caches, performance counters, and the like. These registers, accessible via the RDMSR and WRMSR instructions, were added with the Pentium and later-model 486 processors. 0000001Bh