experimental loop boot Master Boot Record (do nothing)

addressing.asm

; ; A simple boot sector program that demonstrates addressing. ;
mov ah, 0x0e ; int 10/ah = 0eh -> scrolling teletype BIOS routine

; First attempt
mov al, the_secret
int 0x10
; Does this print an X?

; Second attempt
mov al, [the_secret]
int 0x10
; Does this print an X?

; Third attempt
mov bx, the_secret
add bx, 0x7c00
mov al, [bx]
int 0x10
; Does this print an X?

; Fourth attempt
mov al, [0x7c1e]
int 0x10
; Does this print an X?

jmp $ ; Jump forever.

the_secret: db "X"

; Padding and magic BIOS number.

times 510-($-$$) db 0 
dw 0xaa55

addressing2.asm

org 0x7c00
; ; A simple boot sector program that demonstrates addressing. ;
mov ah, 0x0e ; int 10/ah = 0eh -> scrolling teletype BIOS routine

; First attempt
mov al, the_secret
int 0x10
; Does this print an X?

; Second attempt
mov al, [the_secret]
int 0x10
; Does this print an X?

; Third attempt
mov bx, the_secret
add bx, 0x7c00
mov al, [bx]
int 0x10
; Does this print an X?

; Fourth attempt
mov al, [0x7c1e]
int 0x10
; Does this print an X?

jmp $ ; Jump forever.

the_secret: db "X"

; Padding and magic BIOS number.

times 510-($-$$) db 0 
dw 0xaa55

boot1.asm

loop:
jmp loop
times 510-($-$$) db 0
dw 0xaa55

conditional.asm

mov bx, 30
if (bx <= 4) { 
mov al, ’A’ 
} else if (bx < 40) { 
mov al, ’B’ 
} else { 
mov al, ’C’ 
}
mov ah, 0x0e ; int=10/ah=0x0e -> BIOS tele -type output 
int 0x10 ; print the character in al
jmp $ 
; Padding and magic number. 
times 510-($-$$) db 0 
dw 0xaa55

Hello.asm

; ; A simple boot sector that prints a message to the screen using a BIOS routine. ;
mov ah, 0x0e ; int 10/ah = 0eh -> scrolling teletype BIOS routine
mov al, 'H'
int 0x10
mov al, 'e'
int 0x10
mov al, 'l'
int 0x10
mov al, 'l'
int 0x10
mov al, 'o'
int 0x10

jmp $ ; Jump to the current address (i.e. forever).

; ; Padding and magic BIOS number. ;
times 510-($-$$) db 0 ; Pad the boot sector out with zeros

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

stack.asm

; 
; A simple boot sector program that demonstrates the stack. 
; 
mov ah, 0x0e ; int 10/ah = 0eh -> scrolling teletype BIOS routine

mov bp, 0x8000 ; Set the base of the stack a little above where BIOS 
mov sp, bp ; loads our boot sector - so it won’t overwrite us.

push 'A' ; Push some characters on the stack for later 
push 'B' ; retreival. Note , these are pushed on as 
push 'C' ; 16-bit values , so the most significant byte 
	 ; will be added by our assembler as 0x00.

pop bx ; Note , we can only pop 16-bits , so pop to bx 
mov al, bl ; then copy bl (i.e. 8-bit char) to al 
int 0x10 ; print(al)
pop bx ; Pop the next value 
mov al, bl 
int 0x10 ; print(al)
mov al, [0x7ffe] ; To prove our stack grows downwards from bp, 
		 ; fetch the char at 0x8000 - 0x2 (i.e. 16-bits) 
int 0x10 ; print(al)
jmp $ ; Jump forever.
; Padding and magic BIOS number.
times 510-($-$$) db 0 
dw 0xaa55