Input
 utc1
    Binary timestamp or relative binary timestamp.
 utc2
    Binary timestamp or relative binary timestamp.
    Output
 result
    Resulting binary timestamp or relative binary timestamp,
    depending on the operation performed:
    o  absolute time - absolute time = relative time
    o  relative time - relative time = relative time
    o  absolute time - relative time = absolute time
    o  relative time - absolute time is undefined. See NOTES.