of Microprocessors

MUSIC SYNTHESIS SOFTWARE 695
executed. When staccato is specified, the sustain duration is made unconditionally
zero.
Obviously, with so many options in statement construction, a great
variety of note specifications is possible. Below is a list of some legal specifications
and how they are interpreted:
97 3C4Q Voice 3, middle C, quarter note duration (the 97 is a tag
and is not processed)
4E@4E. Voice 4, E-flat just above middle C, dotted eighth duration
(equivalent to 3/16)
2F#3S3S Voice 2, F-sharp just below middle C, part of a sixteenth
note triplet in which three notes take the time normally
required by two of them. Staccato articulation.
19B@5Q3.. S What a mess! The duration should evaluate to 1/4 X 2/3 X
3/2 X 3/2 = 9/24. Voice 19 and staccato articulation are
specified.
In a long score, much of this information seems to be redundant. For example,
a melody line might run for dozens of notes in the same octave, yet the
octave number must be specified for each note. If it weren't for the fact that
several notes with the same voice ID can be playing simultaneously, it would
be easy to have the NOTRAN interpreter assume octave numbers. Ofcourse,
the melody could just as well be split between two octaves and such assumptions
would probably lead to numerous errors. Again, a general solution to
this and other redundancies is left to the reader.
Percussive note specifications are much simpler than tones because only
the voice number really has to be specified. The form: Pn is used where the P
signals a percussive voice and n refers to the ID of a percussive voice definition.
For convenience in certain situations, a duration specification identical
to that described above can be appended.
Sequencing and Overlap
Now that the events themselves are fully specified, all that remains is to
define their sequencing, which relies on just two simple, but very powerful,
concepts. The first is that every note statement represents a distinct point in
time. These time points are in the same sequence as the note statements. All
of the events within a single note statement start at the point in time
corresponding to the statement. Once started, each event runs for its duration
and stops when finished, completely independent of other events started by
this or earlier statements.
The second key concept involves spacing of the time points. Simply
put, the shortest specified duration in a note statement determines the amount
of real time that elapses until the next note statement is executed. Thus, if a
note statement specifies a quarter-note event, two eighth-note events, and a
sixteenth-note event, time equal to a sixteenth-note duration will elapse