; x86-16 BIOS bootloader
[BITS 16]
[ORG 0x7C00]
; jmp 0x7C00:start
start:

call GetChar
jmp start

; REGISTERS
;       SP: 'top of memory'
;	BP: points to variable map
;	others: general purpose
GetChar:
xor     AX,AX			; clear AH
int     0x16			; read key via BIOS
; read key is now in AL
; fallthrough to PutChar to echo read key

PutChar:
mov	AH,0xe		; TTY mode
int	0x10		; print character in AL
cmp     AL, 13          ; if \r, print \r\n and return \n
jne     .ret
mov     AL, 10
call    PutChar
.ret:   ret


; fill up sector, add boot signature
TIMES 510 - ($ - $$) db 0
DW 0xAA55