Abstract: A digital signal processing system for executing instructions, including a program memory which stores the instructions and a program control unit for receiving and processing a sequence of the instructions to generate control signals for controlling operation of the system, and a loop circuit for use in such a program control unit. The loop circuit controls execution of a loop (preferably a nested loop) of a sequence of the instructions. Preferably, the loop circuit includes loop registers for storing loop start and end addresses and loop count values, and logic circuitry for implementing loops (including nested loops) in response to the addresses and count values in the loop registers. The loop circuit is initialized by loading appropriate addresses and values into the loop registers.