bios.txt

# refrence from os-dev

;
; A simple  boot  sector  program  that  loops  forever.
;

loop:                     ; Define a label , "loop", that  will  allow; us to jump  back to it , forever.
                          ; Use a simple  CPU  instruction  that  jumps

jmp  loop                 ; to a new  memory  address  to  continue  execution.
                          ; In our case , jump to the  address  of the  current
                          ; instruction.
                        
times  510-($-$$) db 0    ; When  compiled , our  program  must  fit  into  512 bytes ,
                          ; with  the  last  two  bytes  being  the  magic  number ,
                          ; so here , tell  our  assembly  compiler  to pad  out  our
                          ; program  with  enough  zero  bytes (db 0) to  bring  us to the
                          ; 510th  byte.

dw 0xaa55                 ; Last  two  bytes (one  word) form  the  magic  number ,
                          ; so BIOS  knows  we are a boot  sector.