Zero-overhead loop controller that implements multimedia algorithms

Multimedia algorithms generally consist of regular repetitive loop constructs. The authors present a novel control unit design for implementing such loop intensive algorithms. The proposed architecture, termed a zero-overhead loop controller (ZOLC) exploits the regularity of computations, which is a common characteristic of multimedia algorithms, in order to efficiently support the corresponding datapaths. The ZOLC controls the operations in datapath modules by activating/deactivating their corresponding controlling FSMs. Algorithmic flow dependencies, which determine the appropriate loop sequencing, are mapped onto a look-up table (LUT). For another algorithm to execute, only the LUT context and the FSM configurations have to be reprogrammed, assuming a generic datapath. Thus, partial reconfiguration possibilities to implement multimedia algorithms on programmable platforms can be exploited. As proof-of-concept, implementations of algorithms of the multimedia domain are investigated to evaluate the performance of the proposed unit, against other methods of control. Also, a full-search motion estimation processor employing the ZOLC is synthesised. It is shown that the ZOLC provides flexibility by supporting various algorithms of the multimedia field with performance improvements of up to 2.1 over conventional control methods.