HUB meets posit: arithmetic units implementation

Abstract

The posit (TM) format was introduced in 2017 as an alternative to replacing the widespread IEEE 754. Posit arithmetic provides reproducible results across platforms and possesses tapered accuracy, among other improvements. Nevertheless, despite the advantages provided by such a format, their functional units are not as competitive as the IEEE 754 ones yet. The HUB approach was presented in 2016 to reduce the hardware cost of floating-point units. In this brief, we present HUB posit, a new format to mitigate the hardware overhead of posit units. Results show that it is possible to reach up to 15% and 12% in terms of area-delay product for adders and multipliers, respectively, while maintaining a similar level of accuracy. In addition, synthesis results show that HUB posit units are able to reach higher frequencies than conventional ones.