INT 62 u - FGDRIVER v4.02 - "FG_INTKEY" - GET KEYSTROKE, NO WAIT
	AX = 0063h
	ES:BX -> variable pointer record (see #03489)
Return: variables updated
Notes:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474 at AX=0000h)
	If the keyboard buffer is empty, both the ASCII and extended keycodes
	  are set to 00h
SeeAlso: AX=000Ah,AX=0046h,AX=0069h,AX=00DEh,INT 16/AH=01h


Format of FGDRIVER INTKEY variable pointer record:
Offset	Size	Description	(Table 03489)
 00h	WORD	segment of BYTE buffer for ASCII keycode
 02h	WORD	offset of BYTE buffer for ASCII keycode
 04h	WORD	segment of BYTE buffer for extended keycode
 06h	WORD	offset of BYTE buffer for extended keycode