CWD - Convert Word to Doubleword



	Usage:	CWD
	Modifies flags: None


	Extends sign of word in register AX throughout register DX forming
	a doubleword quantity in DX:AX.


				 Clocks			Size
	Operands	 808x  286   386   486		Bytes

	none		  5	2     2	    3		  1


	- see Instruction Timing