INT 21 - CED (Command EDitor) - INSTALLABLE COMMANDS
	AH = FFh
	AL = subfunction
	    00h add installable command
		BL = mode
		    bit 0 = 1 callable from DOS prompt
		    bit 1 = 1 callable from application
		DS:SI -> CR-terminated command name
		ES:DI -> FAR routine entry point
	    01h remove installable command
		DS:SI -> CR-terminated command name
	    02h reserved, may be used to test for CED installation
Return: CF clear if successful
	CF set on error
	    AX = error code
		01h invalid function
		02h command not found (subfunction 01h only)
		08h insufficient memory (subfunction 00h only)
		0Eh bad data (subfunction 00h only)
	AH = FFh if CED not installed
Program: CED is a shareware DOS command-line enhancer by Christopher J. Dunford
SeeAlso: AX=0A00h
                                                                                

INT 21 - DOSED.COM - INSTALLATION CHECK                                         
	AH = FFh
	DS:SI -> "DOSED"
	ES = 0000h
Return: ES:DI -> "DOSED" if installed
Program: DOSED is a free DOS commandline editor/history buffer by Sverre H.
	  Huseby