org 0

; Use Code segment as Data segment
push cs
pop ds

mov si, textError
call DisplayMessageZ

mov si, textNewline
call DisplayMessageZ

mov si, textError
mov cx, 4
call DisplayMessageX

HANG:
jmp HANG

; Message is at DS:SI, read up to NUL char
DisplayMessageZ:
     lodsb										; load next character
     or		al, al								; test for NUL character
     jz		.DONE
     mov	ah, 0x0E							; BIOS teletype
     mov	bh, 0x00							; display page 0
     mov	bl, 0x07							; text attribute
     int	0x10								; invoke BIOS
     jmp	DisplayMessageZ
.DONE:
     ret

; Message is at DS:SI, read CX chars
DisplayMessageX:
     lodsb										; load next character
     or		al, al								; test for NUL character
     jz		.DONE
     mov	ah, 0x0E							; BIOS teletype
     mov	bh, 0x00							; display page 0
     mov	bl, 0x07							; text attribute
     int	0x10								; invoke BIOS
     loop	DisplayMessageX
.DONE:
     ret


textError db "Boot stage 2 - Hello!", 0x00
textNewline db 0x0D, 0x0A, 0x00

TIMES 512-($-$$) DB 0