electronics Article Coarse-Grained Reconfigurable Computing with the Versat Architecture João D. Lopes 1 , Mário P. Véstias 2,* , Rui Policarpo Duarte 1 , Horácio C. Neto 1 and José T. de Sousa 1 1 INESC-ID, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal;
[email protected] (J.D.L.);
[email protected] (R.P.D.);
[email protected] (H.C.N.);
[email protected] (J.T.d.S.) 2 INESC-ID, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisbon, Portugal * Correspondence:
[email protected]; Tel.: +351-218-317-000 Abstract: Reconfigurable computing architectures allow the adaptation of the underlying datapath to the algorithm. The granularity of the datapath elements and data width determines the granularity of the architecture and its programming flexibility. Coarse-grained architectures have shown the right balance between programmability and performance. This paper provides an overview of coarse-grained reconfigurable architectures and describes Versat, a Coarse-Grained Reconfigurable Array (CGRA) with self-generated partial reconfiguration, presented as a case study for better under- standing these architectures. Unlike most of the existing approaches, which mainly use pre-compiled configurations, a Versat program can generate and apply myriads of on-the-fly configurations. Partial reconfiguration plays a central role in this approach, as it speeds up the generation of incrementally different configurations. The reconfigurable array has a complete graph topology, which yields un- precedented programmability, including assembly programming. Besides being useful for optimising programs, assembly programming is invaluable for working around post-silicon hardware, software, Citation: Lopes, J.D.; Véstias, M.P.; Duarte, R.P.; Neto, H.C.; de Sousa, J.T.