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Radix-2 Multioperand and Multiformat Streaming Online Addition
June 2012 (vol. 61 no. 6)
pp. 790-803
Julio Villalba Moreno, University of Malaga, Malaga
Tomas Lang, University of California at Irvine, Irvine
Javier Hormigo, University of Malaga, Malaga
In this paper, we present multioperand radix-2 online addition using different data representations (signed-digit, two's complement, and carry-save), in particular cases in which operands with different representations are added. We use the previously defined online full adder (olFA) as a component to build different multioperand online architectures. To merge data with different representations, an inner conversion of data is performed, eliminating any conversion stage and penalty time. We propose a technique to build multioperand trees efficiently and give six practical rules to deal with different kinds of data in the same adder. For addition of a stream of data, we determine the minimum number of separation cycles required to isolate two successive computations and propose a novel hardware technique that eliminates completely the separation cycles, resulting in the maximum throughput possible.

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Index Terms:
Online addition, multioperand, signed-digit, carry-save.
Julio Villalba Moreno, Tomas Lang, Javier Hormigo, "Radix-2 Multioperand and Multiformat Streaming Online Addition," IEEE Transactions on Computers, vol. 61, no. 6, pp. 790-803, June 2012, doi:10.1109/TC.2011.97
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