Methods are provided for effecting functional control of program flow and/or data flow in digital signal processors and in processors which have closed and separated modules for effecting the program and data flow control or which operate in parallel arithmetic-logic units. The methods enhance the functionality of the signal processor to such an extent that the units of the processor, without time delays, are adapted, with regard to their energy consumption, to the latest demands of signal processing. The methods provide additional possibilities for saving energy which are enabled by algorithm-related shutdown of functional units. An external hardware-related signal input into the processor or a software-related state output from the program flow in the processor may be used to trigger an interruption in the clock pulse supply for the respective functional units for the period of time during which these functional units are not used.