SOUND
=====

The SOUND vocabulary implements a set a words that can play music and
sounds.

An example is given in the DEMO-SOUND.FS file, to hear the result
execute

    INCLUDE DEMO-SOUND.FS
    DEMO


Definitions
-----------

The following constants can be used to set the sound registers
directly

    VOICE1
    VOICE2
    VOICE3
    NOISE

Alternatively they can be used to define sequences of notes in a
tune.


VOLUME   ( vol -- )

    Set the sound volume.

TUNE nnnn

    Define a sequence of notes that can be played.

NOTE,   ( delta val reg -- )

    Define a change to a sound register that should occur at the time
    delta since the tune started. Time deltas are given in jiffies.

PLAY   ( tune -- tf )

    Play the next note in a tune at the appropriate time. Return -1
    when the tune is complete.
