Sharing of Functional and Special Means in Pipeline Floating-Point Systems with Strongly Connected Versions

Abstract

This paper is dedicated to a problem of designing of the multi-version systems with strongly connected versions in area of pipeline data processing in the floating-point formats. Multi-version systems are directed to parrying of common cause failures, including design errors. This problem is traditionally solved on the basis of creation of the most independent versions which number determines considerable complexity of a system. This leads to restriction in development of the multi-version system. Systems with strongly connected versions are aimed at the solution of the same task, but in the conditions of the maximum connectivity of versions at which the task is feasible. The problem is solved in the presence of at least one right version and means of its search. Sections of modern pipeline systems are the matrix structures constructed of uniform elements with regular connections: parallel adders and shifters, iterative array multipliers and dividers. Such structures allow to form strongly connected versions which search can be carried out by cyclic shift of operands. Pipeline floating-point systems execute processing of the data, presented by mantissas and exponents whose interaction is carried out by means of the operations of normalization and a denormalization on the basis of arithmetic shift. We offer sharing of functional means in performance of operations of normalization and a denormalization with special functions of search of the right version on the basis of joint realization of operations of cyclic and arithmetic shift.