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High-Speed Multioperand Decimal Adders
August 2005 (vol. 54 no. 8)
pp. 953-963
There is increasing interest in hardware support for decimal arithmetic as a result of recent growth in commercial, financial, and Internet-based applications. Consequently, new specifications for decimal floating-point arithmetic have been added to the draft revision of the IEEE-754 Standard for Floating-Point Arithmetic. This paper introduces and analyzes three techniques for performing fast decimal addition on multiple binary coded decimal (BCD) operands. Two of the techniques speculate BCD correction values and correct intermediate results while adding the input operands. The first speculates over one addition. The second speculates over two additions. The third technique uses a binary carry-save adder tree and produces a binary sum. Combinational logic is then used to correct the sum and determine the carry into the next more significant digit. Multioperand adder designs are constructed and synthesized for four to 16 input operands. Analyses are performed on the synthesis results and the merits of each technique are discussed. Finally, these techniques are compared to several previous techniques for high-speed decimal addition.

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Index Terms:
Index Terms- Computer arithmetic, decimal arithmetic, multioperand adders, hardware designs.
Citation:
Robert D. Kenney, Michael J. Schulte, "High-Speed Multioperand Decimal Adders," IEEE Transactions on Computers, vol. 54, no. 8, pp. 953-963, Aug. 2005, doi:10.1109/TC.2005.129
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