AY8930 instrument editor

AY8930 instrument editor consists of these macros.

Volume: volume sequence
Arpeggio: pitch in half-steps
Noise Freq: AY8930 noise generator frequency sequence
Waveform: selector of sound type: pulse wave tone, noise or envelope generator
Pitch: fine pitch
Phase Reset: trigger restart of waveform
Duty: duty cycle of a pulse wave sequence
Envelope: allows shaping an envelope
AutoEnv Num: sets the envelope to the channel's frequency multiplied by numerator
AutoEnv Den: sets the envelope to the channel's frequency divided by denominator
Noise AND Mask: alters the shape/frequency of the noise generator, allowing to produce various interesting sound effects and even PWM phasing
Noise OR Mask: see above