Non-arithmetic carry chains for reconfigurable fabrics

Abstract

Reconfigurable fabrics cater to a wide variety of applications, but have adopted specialized components to allow efficient implementation of performance-critical arithmetic operations. Carry chains have been integrated into the fabric typically as an optimized ripple-carry chain. However, in non-arithmetic operations the carry chain goes unused, when it could be a valuable adjacent-cell interconnect resource. This paper presents a cell architecture facilitating reuse, as well as an analysis of the potential benefits of reuse for an sampling of common of algorithms using commercial FPGAs. Technology map experiments indicate that a variety of applications can benefit from reuse, with utilized routing resources reduced by up to 13% and maximum clock frequency increased by up to 47%.