INT 2F U - ANARKEY.COM v3+ - ANARKMD API
        AX = E303h
        BL = function
            01h toggle insert mode
            02h display contents of history buffer
            03h write history buffer to file
                ES:DX -> file name
            04h clear history buffer
            05h undefine all aliases
            06h show aliases
            07h list programs using Unix switchar
            08h jump to bottom of history buffer
            09h (v4.0) add string to history buffer
                ES:DX -> ASCIZ string
            0Ah (v4.0) ???
                ES:DX -> ???
            0Bh (v4.0) copy string to edit buffer for use as next input line
                ES:DX -> ASCIZ string
            0Ch (v4.0) ???
            0Dh (v4.0) copy ??? to ???
            0Eh (v4.0) ???
            0Fh (v4.0) ???
            10h (v4.0) set ??? flag
            11h (v4.0) display error message about running in EMS under Windows
Return: ???