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;; boot.stage2.asm
[bits 16]
[org 0x7e00]
%include "common.asm"
jmp 0x0000:_s2_entry
_s2_entry:
cli
xor ax, ax
mov ds, ax
mov si, DAP_kernel
mov ah, 0x42
int 0x13
jc _kernel_load_err
jmp _kernel_loaded
_kernel_load_err:
mov si, boot_kernel_err
call _print_string
jmp $
_kernel_loaded:
mov si, boot_s2_msg
call _print_string
call _enable_a20 ; Enable A20 line
lgdt [GDT32_ptr] ; Load GDT
;; Setup Protected Mode
mov eax, cr0
or eax, 1
mov cr0, eax
jmp CODE_SEG32:_protected_mode
[bits 32]
_protected_mode:
mov ax, DATA_SEG32
mov ds, ax
mov ss, ax
mov esp, 0x90000
and esp, 0xFFFFFFF0 ; Align to 16-byte boundary
mov esi, boot_protmode_msg
call _print_string_pm_vga
call 0x10000
boot_s2_msg:
db "Entering Stage 2", 13, 10, 0
boot_protmode_msg:
db "Enabling Protected Mode", 13, 10, 0
boot_kernel_err:
db "Error loading kernel from disk", 13, 10, 0
align 16
DAP_kernel:
db 0x10
db 0
dw 1 ; Number of sectors
dw 0x0000
dw 0x1000 ; Offset
dq 66 ; Starting sector
%include "boot.stage1.print.asm"
%include "boot.stage2.a20.asm"
%include "boot.stage2.gdt32.asm"
%include "boot.stage2.print.asm"
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