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IBM Journal of Research and Development  
Volume 25, Number 1, Page 83 (1981)
Network Problem Determination
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A Number Representation Convertor for Magnetic Bubble String Comparators

by G. Bongiovanni, C.-K. Wong
Conventionally, there are four common ways to represent negative numbers, namely, 1's-complement, 2's-complement, signed-magnitude, and excess-2m–1. In all these representations except the last one (excess-2m–1), 1 is used as the sign bit to denote negative numbers. However, in a recently reported magnetic bubble device, using 1 as the sign bit for negative numbers may cause problems when two numbers are compared. In this paper we define a new number representation (called B1's-complement), and we propose a simple, read-free device for converting numbers represented in any of the above standard representations to either the excess-2m–1 or the B1's-complement representation.
Related Subjects: Algorithms; Magnetic bubble technology