PUSH - Push Word onto Stack

	Usage:	PUSH	src
		PUSH	immed	(80188+ only)
	Modifies flags: None


	Decrements SP by the size of the operand (two or four, byte values
	are sign extended) and transfers one word from source to the stack
	top (SS:SP).

				 Clocks			Size
	Operands	 808x  286   386   486		Bytes

	reg16	 	11/15	3     2     1		  1
	reg32	 	  -	-     2     1		  1
	mem16		16+EA	5     5     4	 	 2-4  (W88=24+EA)
	mem32	   	  -	-     5     4		 2-4
	segreg		10/14	3     2     3		  1
	immed		  -	3     2     1		 2-3


	- see Instruction Timing