79 lines
1.2 KiB
NASM
79 lines
1.2 KiB
NASM
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section .text
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org 0x7c00
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start:
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push dx
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mov ax, 0
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mov ds, ax
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mov es, ax
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mov gs, ax
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mov fs, ax
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mov ax, 0x7e00
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mov ss, ax
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mov sp, 256
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mov bp, 256
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mov ax, 0x7c00
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add ax, 446
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; ax now points to the start of the partition table
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mov di, 0
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.search_partition:
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mov bx, ax
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add bx, 4
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mov cl, [bx]
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cmp cl, 0x9d
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je .found_partition
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inc di
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cmp di, 4
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je .no_boot_partition
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add ax, 16
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.found_partition:
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mov bx, ax
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add bx, 14
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mov cx, [bx] ; more than 65536 sectors will NOT be
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; supported for the bootloader's partition!
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mov bx, 0x8000
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mov es, bx
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mov di, 0x0000
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mov bx, ax
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inc bx
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; bx now points to the CHS-address of the first sector
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; of the bootloader's partition.
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mov dx, [bx]
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mov ah, dh ; head
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mov bl, dl ; sector
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add bx, 2
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; bx now points to the CHS-cylinder of the first sector
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; of the bootloader's partition.
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mov al, [bx] ; cylinder
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call load_sectors
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.no_boot_partition:
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hlt
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%include "gdt.asm"
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%include "utility.asm"
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