Tone generating circuitry for reading out one-shot and sustaining waveforms

A tone generating apparatus, comprising:

• a wave memory within which is stored a plurality of first tone waveform data each of which has a preselected length extracted from an attack portion of a corresponding plurality of musical tones and a plurality of second tone waveform data each of which has a preselected length following associated first tone waveform data;
• read means for reading a selected first tone waveform data of said plurality of first waveform data only once from said wave memory and subsequently reading associated second tone waveform data of said plurality of second waveform data repeatedly;
• a first predetermined plurality of said plurality of second waveform data having a value of zero so that no musical tone is produced when said first predetermined plurality of second waveform data is read repeatedly and a second predetermined plurality of second waveform data having a value that non-zero so that sustaining musical tones are produced when said second predetermined plurality of second waveform data is read repeatedly;
• tone generating means for generating a musical tone based on said tone waveform data read out by said read means;
• whereby said read means is the only read means required to read musical tones having sustaining portions and musical tones not having sustaining portions.