Abstract: An execution unit for a processing engine comprising first head part circuitry for deriving an intermediate signal from an input signal. The execution unit also comprises further circuitry which receives the intermediate signal and operates on it to produce a final signal. The further circuitry is typically configured to perform one or more signal processing functions in combination with the first circuitry, and generally comprises separate circuitry for each function. The intermediate signal is configured to be usable by each of the separate circuitry.

Abstract: A processor (100) is provided that is a programmable fixed point digital signal processor (DSP) with variable instruction length, offering both high code density and easy programming. Architecture and instruction set are optimized for low power consumption and high efficiency execution of DSP algorithms, such as for wireless telephones, as well as pure control tasks. The processor includes an instruction buffer unit (106), a program flow control unit (108), an address/data flow unit (110), a data computation unit (112), and multiple interconnecting busses. Dual multiply-accumulate blocks improve processing performance. A memory interface unit (104) provides parallel access to data and instruction memories. The instruction buffer is operable to buffer single and compound instructions pending execution thereof. A decode mechanism is configured to decode instructions from the instruction buffer. The use of compound instructions enables effective use of the bandwidth available within the processor.