TITLE:
Fast Signed-Digit Multi-operand Decimal Adders
AUTHORS:
Jeff Rebacz, Erdal Oruklu, Jafar Saniie
KEYWORDS:
Computer Arithmetic, Decimal Arithmetic, Signed-Digit, Multi-operand Adder, BCD
JOURNAL NAME:
Circuits and Systems,
Vol.2 No.3,
July
20,
2011
ABSTRACT: Decimal arithmetic is desirable for high precision requirements of many financial, industrial and scientific applications. Furthermore, hardware support for decimal arithmetic has gained momentum with IEEE 754-2008, which standardized decimal floating-point. This paper presents a new architecture for two operand and multi-operand signed-digit decimal addition. Signed-digit architectures are advantageous because there are no carry-propagate chains. The proposed signed-digit adder reduces the critical path delay by parallelizing the correction stage inherent to decimal addition. For performance evaluation, we synthesize and compare multiple unsigned and signed-digit multi-operand decimal adder architectures on 0.18μm CMOS VLSI technology. Synthesis results for 2, 4, 8, and 16 operands with 8 decimal digits provide critical data in determining each adder's performance and scalability.