The Effect of Granularity on the Design of Decimal Arithmetic Reconfigurable Units

Recently, decimal arithmetic has received renewed attention in certain application domains such as financial computations. This is mostly due to the demand for more accurate decimal number representation and calculation in those applications. While decimal arithmetic may be implemented in software and hardware, the latter form offers higher speeds and better performance. Traditionally, hardware decimal units have been designed as application-specific specialized hardware modules. However, emerging designs have come with some degree of reconfigurablility. But there is no research on the effects of reconfigurability parameters, such as granularity and degree of flexibility, on the overall characteristics of decimal hardware modules .In this paper, it will be shown that bit-level granularity is not suitable for decimal reconfigurable adders. Instead, digit-level granularity will lead to superior designs. The synthesis results indicate that increasing granularity level provides an area improvement of %12 and power improvement of %13.4. Unlike adders, increasing the granularity of decimal multipliers has an adverse effect on their quality and may cause up to %75 increase in their area and power consumption.