Network, Computer and Programming Resources

Cpu - STARTUP IPI

A type of APIC interprocessor interrupt that is similar to an NMI with an embedded vector. It does not cause any change of state, but merely causes the targeted processor to start executing in Real Mode from address 000VV000h, VV being an 8-bit vector which is part of the IPI message. Startup vectors are limited to a 4K page boundary in the first 1 MB of the address space. STARTUP IPIs are not maskable, and can be issued at any time. The benefit of STARTUP-IPI compared to NMI is that it does not require the targeted APIC to be enabled, and it does not require the interrupt table to be programmed. Thus, the operating system's initialization procedure can use it to wake up an AP that has been sleeping since RESET or INIT. The STARTUP IPI is not supported by the 82489DX APIC.