Configurable RTL model for level-1 caches

Abstract

Level-1 (L1) cache memories are complex circuits that tightly integrate memory, logic, and state machines near the processor datapath. During the design of a processor-based system, many different cache configurations that vary in, for example, size, associativity, and replacement policies, need to be evaluated in order to maximize performance or power efficiency. Since the implementation of each cache memory is a time-consuming and error-prone process, a configurable and synthesizable model is very useful as it helps to generate a range of caches in a quick and reproducible manner. Comprising both a data and instruction cache, the RTL cache model that we present in this paper has a wide array of configurable parameters. Apart from different cache size parameters, the model also supports different replacement policies, associativities, and data write policies. The model is written in VHDL and fits different processors in ASICs and FPGAs. To show the usefulness of the model, we provide an example of cache configuration exploration.