Double Throughput Multiply-Accumulate unit for FlexCore processor enhancements

As a simple five-stage General-Purpose Processor (GPP), the baseline FlexCore processor has a limited set of datapath units. By utilizing a flexible datapath interconnect and a wide control word, a FlexCore processor is explicitly designed to support integration of special units that, on demand, can accelerate certain data-intensive applications. In this paper, we propose the integration of a novel Double Throughput Multiply-Accumulate (DTMAC) unit, whose different operating modes allow for on-thefly optimization of computational precision. For the two EEMBC benchmarks considered, the FlexCore processor performance is significantly enhanced when one DTMAC accelerator is included, translating into reduced execution time and energy dissipation. In comparison to the 32-bit GPP reference, the accelerated 32-bit FlexCore processor shows a 4.37times improvement in execution time and a 3.92times reduction in energy dissipation, for a benchmark with many consecutive 16-bit MAC operations.