INT 60 u - HP 95LX System Manager - LET SYSTEM MANAGER PROCESS EDITING KEYSTROK
        DI = 0403h
        STACK:  2 WORDs unused dummies (for calls from high level languages)
                DWORD   pointer to edit record (see INT 60/DI=0400h)
                WORD    keystroke
                DWORD   pointer to WORD buffer for result code
Return: result code buffer filled with 0001h if editing complete
        STACK unchanged