Exposed Datapath for Efficient Computing
Magnus Björk, Magnus Själander, Lars J. Svensson, Martin Thuresson, John P. Hughes, Kjell Jeppson, Jonas Karlsson, Per Larsson-Edefors, Mary Sheeran, Per Stenström · 2006
Abstract — We introduce FlexCore, which is the first exemplar of a processor based on the FlexSoC processor paradigm. The FlexCore utilizes an exposed datapath for increased performance. Manually scheduled micro-benchmarks yield a performance boost of up to a factor of two over a traditional five-stage pipeline with the same functional units as the FlexCore. The compiler is always capable of scheduling the instructions of a generalpurpose application onto the FlexCore on par with a traditional GPP in terms of cycle count. The flexible interconnect allows the FlexCore datapath to be dynamically reconfigured as a consequence of code generation. Additionally, specialized functional units may be introduced and utilized within the same architecture and compilation framework. The exposed datapath requires a wide control word. The conducted evaluation confirms that this increases the instruction bandwidth and memory footprint. This calls for efficient instruction decoding as proposed in the FlexSoC paradigm. I.