This paper presents and analyzes two different strategies for designing multiformat online decimal adders ($\text{olDFA}_{\text{Mformat}}$). The first strategy uses a code conversion stage plus an online Decimal Full Adder (olDFA); the second one involves designing specific adders by modifying the architecture of the olDFA. These strategies are applied in the design of specific architectures to deal with financial analysis calculations. We use synthesis results to verify the theoretical aspects of the designs and to analyze the robustness and lacks of the strategies. The guidelines presented in the paper are valuable to designers of online multiformat-based solutions.

In this paper we present the design of an on-line adder dealing with two RBCD numbers. This basic element is intended to be be used in any on-line system in which the addition is involved. We obtain the on-line adder by serialization of a recent parallel RBCD adder with minimum latency.To reduce the cycle time a pipelined version is proposed. To deal with data stream the throughput has been reduced to its theoretical minimum possible value by a negligible cost hardware modification. Finally, actual implementation results for 16 digits (i.e. decimal64 format) are presented.