Tinney_Alabsa.asm

BITS 16
start:
   mov ax, 07C0h ; Set up 4K stack space after this bootloader
   add ax, 288 ;  (4096 + 512) / 16 bytes per paragraph
   mov ss, ax
   mov sp, 4096

   mov ax, 07C0h  ; Set data segment to where we're loaded
   mov ds, ax


mov si, boot_message   ; Put message string position into SI
call print_string      ; Call printing routine

jmp $    ; Jump here - infinite loop!

boot_message db 'Booting from floppy...', 0
cs_message db 'CS-DOS Operating System v1.0', 0
creating_message db 'Created for CS3423, Summer 2014', 0
copyright db '(C) Copyright 2014 by Matthew Tinney and Shade Alabsa. All rights reserved.', 0

print_string:   ; Routine: output string in SI to screen
    mov ah, 0Eh  ; 'print char' function is denoted by 0Eh

.repeat:
   lodsb    ; load next byte from SI and increment SI. 
   cmp al, 0s  ; compare to zero to see if end of string. 
   je .done ; if char is zero, we’re at end of string. 
   int 10h  ; Otherwise, print it.
   jmp .repeat
.done: 
   ret

times 510-($-$$) db 0 ; fill remainder of boot sector with 0s up ; to byte 510.
dw 0xAA55   ; The standard PC boot signature of AA 55 ; is placed in bytes 511 and 512.