INT 21,4C - Terminate Process With Return Code

	AH = 4C
	AL = return code (for batch files)

	returns nothing

	- approved method of program termination
	- restores the terminate, Ctrl-Break, and critical error exit
	  addresses, flushes all buffers, frees memory and returns to
	  DOS via the termination handler address
	- does not close FCBs
	- this function is not supported in versions of DOS before 2.x,
	  so use INT 21,0  or	 INT 20  to exit.

	- see also  INT 27   INT 21,31