Function 07h Direct Console Input Without Echo (does not check BREAK)
Get or wait for char at STDIN, returns char in AL
entry AH 07h
return AL character from standard input device
note 1) Extended ASCII codes require two function calls. The first call returns
00h to indicate the next call will return an extended code.
2) No checking for Ctrl-C or Ctrl-PrtSc is done.
3) Input is redirectable.