STOS - Store String (Byte, Word or Doubleword)

	Usage:	STOS	dest
		STOSB
		STOSW
		STOSD
	Modifies flags: None


	Stores value in accumulator to location at ES:(E)DI (even if operand
	is given).  (E)DI is incremented/decremented based on the size of
	the operand (or instruction format) and the state of the Direction
	Flag.	Use with REP prefixes.


				 Clocks			Size
	Operands	 808x  286   386   486		Bytes

	dest		  11	3     4	    5		  1  (W88=15)


	- see Instruction Timing