A low-energy approach for context memory in reconfigurable systems

In most of the works concerning reconfigurable computing, the main objective is system optimization by taking into account the known requirements of a project, such as speedup, energy or area. However, as it will be shown in this paper, although very significant, the impact of the context memory is often ignored. Since the context memory is responsible for keeping configurations of the reconfigurable unit, the word size and hence the number of output bits is orders of magnitude larger than the regular memories, considerably increasing the energy consumption and area occupation. Therefore, in this article we propose a technique to handle these issues, while maintaining system performance. Using as case study a coarse-grain architecture tightly coupled to the MIPS R3000 processor, we show that the context memory can represent up to 63% of the total system energy and, by using the proposed approach, it is possible to save 59% of this amount, without any performance penalties.