2009 19th IEEE International Symposium on Computer Arithmetic Fully Redundant Decimal Arithmetic Saeid Gorgin and Ghassem Jaberipur Dept. of Electrical & Computer Engr., Shahid Beheshti Univ. and School of Computer Science, institute for research in fundamental sciences (IPM), Tehran, Iran
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[email protected] Abstract In both decimal and binary arithmetic, partial products in multipliers and partial remainders in Hardware implementation of all the basic radix-10 dividers are often represented via a redundant number arithmetic operations is evolving as a new trend in the system (e.g., Binary signed digit [11], decimal carry- design and implementation of general purpose digital save [5], double-decimal [6], and minimally redundant processors. Redundant representation of partial decimal [9]). Such use of redundant digit sets, where products and remainders is common in the the number of digits is sufficiently more than the radix, multiplication and division hardware algorithms, allows for carry-free addition and subtraction as the respectively. Carry-free implementation of the more basic operations that build-up the product and frequent add/subtract operations, with the byproduct of remainder, respectively. In the aforementioned works enhancing the speed of multiplication and division, is on decimal multipliers and dividers, inputs and outputs possible with redundant number representation. are nonredundant decimal numbers. However, a However, conversion of redundant results to redundant representation is used for the intermediate conventional representations entails slow carry partial products or remainders. The intermediate propagation that can be avoided if the results are kept additions and subtractions are semi-redundant in redundant format for later use as operands of other operations in that only one of the operands as well as arithmetic operations.