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global smp_start
global LLOCK
extern smp_main
global gdt_descriptor
; master boot record for application processors
smp_start:
[bits 16]
cli ;switch off interrupts!
lgdt [gdt_descriptor] ;load descriptor table!
;switch on 32-bit protected mode
mov eax, cr0
or eax,0x1
mov cr0, eax
jmp 0x8:init_pm
[bits 32]
LLOCK: dd 0
init_pm:
mov ax, 0x10
mov ds, ax
mov ss, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ebp, 0x7000
mov esp, ebp
call boot_32_pm ;continue booting in 32-bit protected mode
boot_32_pm:
mov eax,1
xchg eax, [LLOCK]
cmp eax,1
je boot_32_pm
mov ebp, 0x7000
mov esp, ebp
call smp_main
jmp $ ; should never be reached
gdt_start:
gdt_null: ;null descriptor (2 x 4 bytes)
dd 0x0
dd 0x0
gdt_code:
; flags:
; present: 1 / privilege: 00 / type: 1
; code: 1 / conforming: 0 / readable: 1 / accessed: 0
; granularity: 1 / 16-bit default: 1 / 64-bit seg: 0 / AVL: 0
dw 0xffff ;limit
dw 0x0 ;base
db 0x0 ;base
db 10011010b ;flags
db 11001111b ;flags & seg.limit
db 0x0 ;base
gdt_data:
; flags:
; code: 0 / expand down: 0 / writable: 1 / accessed: 0
dw 0xffff
dw 0x0
db 0x0
db 10010010b
db 11001111b
db 0x0
gdt_end:
gdt_descriptor:
dw gdt_end-gdt_start-1
dd gdt_start
;CODE_SEG equ gdt_code - gdt_start
;DATA_SEG equ gdt_data - gdt_start
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