A Binary Stacker via Barrel Shifters

Abstract

Stacking, or grouping all set bits in a binary sequence together, is used recently to design a fast parallel (6,3) counter, and a novel approximate (4,2) compressor. These circuits use blocks of a stacking circuit, that can stack only three bits long binary sequences. This paper presents a new procedure to stack set bits in an N bits long binary sequence, for any N, in $\mathrm{O}({log}[N])$ stages. Design of fast parallel binary counters using the proposed stacking method, is also discussed.