1. A method comprising: executing in parallel sets of machine-code instructions with processing elements to generate digital waveforms for Musical Instrument Digital Interface (MIDI) voices present in a MIDI frame, wherein machine-code instructions in the sets of machine-code instructions are instances of machine-code instructions defined in an instruction set that is specialized for generation of digital waveforms for MIDI voices; outputting, with control units in the processing elements, control signals to arithmetic logic units (ALUs) in the processing elements to instruct the ALUs to perform arithmetic operations, wherein the ALUs are specialized to perform the arithmetic operations to generate digital waveforms for MIDI voices; aggregating the digital waveforms for the MIDI voices to generate an overall digital waveform for the MIDI frame; and outputting the overall digital waveform.