To use LSE with the MACRO-64 language, you must name your program
    source file with a .M64 file extension. For example, to edit a
    file named TEST.M64, enter the following command:

    $ LSE TEST.M64

    Using the .M64 file extension invokes the LSE editor and places
    you in the MACRO-64 language environment.

    If you choose to use a different file extension, you can still
    use LSE in the MACRO-64 language environment. For example, to
    edit a file named TEST.ASM, enter the following command:

    $ LSE/LANGUAGE=MACRO64 TEST.ASM

    If you use LSE with MACRO-64, and you want the same behavior on
    the OpenVMS Alpha operating system as on the OpenVMS VAX operating
    system, enter the following LSE command:

    $ SET COMMAND LANGUAGE VMS