INT 16 - KEYBOARD - CHECK FOR 122-KEY KEYSTROKE (122-key kbd support only)
	AH = 21h
Return: ZF set if no keystroke available
	ZF clear if keystroke available
	    AH = BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. scan code
	    AL = ASCII character
Notes:	use AH=09h to determine whether this function is supported
	some versions of the IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. Technical Reference erroneously report
	  that CF is returned instead of ZF
	K3PLUS v6.00+ supports this function as an alias of AH=11h
SeeAlso: AH=01h,AH=09h,AH=11h,AH=20h,AH=21h