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Variable-Width Rotation Scheme for Interleaving

IP.com Disclosure Number: IPCOM000038686D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31

Publishing Venue

IBM

Related People

Authors:
McAuliffe, KP Pfister, GP [+details]

Abstract

A method is described herein for effecting a variable-amount right rotate of a variable-width bit-field to support a data interleaving function. The method uses less hardware than a crossbar switch to perform the interleave function. The objective of the method presented is to replace the variable-width rotate with a fixed-width logical shift; the number of bit positions shifted is still a variable amount. Let an address to be interleaved be defined as having a node number field of n bits and a storage offset of m bits, as shown in Fig. 1. Let the bits in the node number be labeled HSn-1 to HSO, where HSn-1 is the most significant bit (MSB). Let the storage offset bits be labeled LSm-1 to LSO similarly. The maximum interleave amount for the address (in Fig. 1) is n.