INT 16 - KEYBOARD - GET KEYSTROKE
AH = 00h
Return: AH = BIOS scan code
AL = ASCII character
Notes:  on extended keyboards, this function discards any extended keystrokes,
returning only when a non-extended keystroke is available
the BIOS scan code is usually, but not always, the same as the hardware
scan code processed by INT 09.  It is the same for ASCII keystrokes
and most unshifted special keys (F-keys, arrow keys, etc.), but
differs for shifted special keys.
SeeAlso: AH=05h,AH=10h,AH=20h,INT 18/AH=00h

See also: 1601

1600 - KEYBOARD - GET KEYSTROKE