TCONMAP: Technology Mapping for Parameterised FPGA Configurations

Parameterised configurations are FPGA configuration bitstreams in which the bits are defined as functions of user-defined parameters. From a parameterised configuration, it is possible to quickly and efficiently derive specialised, regular configuration bitstreams by evaluating these functions. The specialised bitstreams have different properties and functionality depending on the chosen values of the parameters. The most important application of parameterised configurations is the generation of specialised configuration bitstreams for Dynamic Circuit Specialisation, a technique for optimising circuits at runtime using partial reconfiguration of the FPGA. Generating and using parameterised configurations requires a new FPGA tool flow. In this article, we present a new technology mapping algorithm for parameterised designs, called TCONMAP, that can be used to produce parameterised configurations in which both the configuration of the logic blocks and routing is a function of the parameters. In our experiments, we demonstrate that in using TCONMAP, the depth and area of the mapped circuit is close to the minimal depth and area attainable. Both Dynamic Circuit Specialisation and fine-grained modular reconfiguration are extracted by TCONMAP from the HDL description of the design requiring only simple parameter annotations.