INT 21 - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE
AH = 4Ch
AL = return code
Return: never returns
Notes:  unless the process is its own parent (see AH=26h, offset 16h in PSP),
all open files are closed and all memory belonging to the process
is freed
all network file locks should be removed before calling this function
SeeAlso: AH=26h,AH=4Bh,AH=4Dh,INT 15/AH=12h/BH=02h,INT 20,INT 22

See also: 2100

214C - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE