i was converting an ordinary floppy into bootable via the following code which i downloaded from some site i dont remember. it works perfectly well but i m unable to understand some parts of the assembly code .if some one will please explain my questioins
source: (there is a makefile also)
.global _start <============== why this "start" begins with an underscore while other labels do not?
.ascii "Loading UniOS 1.1 Beta..."
.byte 10, 13, 0
.ascii "Device not responding to SCSI command."
.ascii "Hit ENTER to continue..."
.ascii "Keyboard not responding to SCSI command."
.ascii "Yes, TazQ is an Internet crack monkey on wheels."
<========================== what is the function of the following few lines?
.byte boottag - .
=============== it seems the above few lines are writing AA55 to 510... th byte of boot sector which ofcourse will tell the BIOS that it is a bootable.but if these three lines can do the job why do we need the whole program?they r never referenced in the program will only this three lines make it a bootable?
thanks in advance.