2018-02-23 16:20:31 +00:00
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[org 0x7c00]
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KERNEL_OFFSET: equ 0x1000 ; kernel memory offset
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mov [BOOT_DRIVE], dl ; store boot drive for later.
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mov bp, 0x9000 ; setup the stack
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mov sp, bp
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mov bx, MSG_REAL_MODE
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call print_string
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call load_kernel ; load our kernel from memory
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call switch_to_pm ; switch to 32-bit protected mode
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jmp $
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%include "print.asm"
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%include "print32.asm"
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%include "disk.asm"
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%include "gdt.asm"
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%include "switch_prot.asm"
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[bits 16]
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load_kernel:
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mov bx, MSG_LOAD_KERNEL
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call print_string
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mov bx, KERNEL_OFFSET ; address to load the kernel to
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2018-02-23 16:39:14 +00:00
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mov dh, 1 ; number of sectors to load
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2018-02-23 16:20:31 +00:00
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mov dl, [BOOT_DRIVE] ; drive to load from
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call disk_load
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mov bx, MSG_KERNEL_LOADED
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call print_string
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ret
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[bits 32]
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BEGIN_PM:
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mov ebx, MSG_PROT_MODE
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call print_string_pm
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call KERNEL_OFFSET
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jmp $
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;;;
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; Data
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BOOT_DRIVE: db 0
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MSG_REAL_MODE: db "Started in 16-bit Real Mode",0
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MSG_PROT_MODE: db "Successfully landed in 32-bit Protected Mode",0
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MSG_LOAD_KERNEL: db "Loading kernel into memory...",0
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MSG_KERNEL_LOADED: db "Successfully loaded kernel into memory",0
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times 510-($-$$) db 0
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dw 0xaa55
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