ENTER - Make Stack Frame (80188+)

	Usage:	ENTER	locals,level
	Modifies flags: None


	Modifies stack for entry to procedure for high level language.
	Operand "locals" specifies the amount of storage to be allocated
	on the stack.	"Level" specifies the nesting level of the routine.
	Paired with the LEAVE instruction, this is an efficient method of
	entry and exit to procedures.


				     Clocks			Size
	Operands	 808x	 286	   386	     486	Bytes

	immed16,0	  -	  11	   10	      14  	  4
	immed16,1	  -	  15	   12	      17  	  4
	immed16,immed8	  -   12+4(n-1) 15+4(n-1)    17+3n	  4


	- see Instruction Timing