A-1. Programming Local Apic For Virtual Wire Mode - Intel MultiProcessor Specification

;-----------------------------------------------------------------------;
; InitLocalAPIC( )
;-----------------------------------------------------------------------;
;
; Initialize the local APIC to virtual wire mode.
;
;-----------------------------------------------------------------------;
SVR equ
LVT1 equ
LVT2 equ
APIC_ENABLED equ
public InitLocalAPIC
InitLocalAPIC proc
push ds
push es
push esi
mov al,080h
out 070h,al
in al,021h
push ax
mov al,0ffh
out 021h,al
in al,0a1h
push ax
mov al,0ffh
out 0a1h,al
extrn pmode_on : near
call pmode_on
;
; The APIC spurious interrupt must point to a vector whose lower
; nibble is 0F, that is 0xF, where x is 0 - F. Here we use Int 00FH,
; which handles spurious interrupts and supplies the necessary IRET.
; This vector is assumed to have already been initialized in memory.
;
; Enable the APIC via SVR and set the spurious interrupt to use Int 00F
;
mov esi,SVR
mov eax,[esi]
and eax,0FFFFFF0FH
or eax,APIC_ENABLED
mov [esi],eax
;
; Program LVT1 as ExtInt, which delivers the signal to the INTR signal of all
; processors' cores listed in the destination as an interrupt that originated
; in an externally-connected interrupt controller.
;
Example A-1. Programming Local APIC for Virtual Wire Mode
Version 1.4
0FEE000F0H
0FEE00350H
0FEE00360H
000000100H
near
; save regs used for APIC init
; ensure NMI disabled
; read primary imr
; save settings
; mask all off
; read secondary imr
; save settings
; mask all off
; switch into real big mode
; read SVR
; clear spurious vector (use vector
00FH)
; bit 8 = 1
; write SVR
System BIOS Programming Guidelines
;
;
;
;
A-3