A novel static prediction scheme for filter cache structures

Energy dissipation in cache memories is becoming a major design issue for embedded microprocessors. Predictive filter cache based instruction cache hierarchy has been shown to effectively reduce the energy-delay product. In this paper, a simplified pattern prediction algorithm is proposed for the filter cache hierarchy. The prediction scheme relies on the static nature of the hit or miss pattern of the instruction access streams. The static patterns are maintained in a small 32x1-bit wide Static Pattern Table (SPT). Our investigations show that the proposed prediction algorithm is superior to that based on Next Fetch Prediction Table (NFPT) for all the benchmarks simulated. With the proposed approach, energy delay product reduction of up to 6.79% was evident when compared with that using NFPT. Moreover, since the prediction scheme is based on the static assignment of patterns, it lends well for area and power efficient implementation than that employs dynamic pattern prediction although it is marginally inferior (i.e. 0.69%) in term of energy delay product.