SRT division architectures and implementations

Abstract

SRT [Sweeney, Robertson and Tocher (1958)] dividers are common in modern floating point units. Higher division performance is achieved by retiring more quotient bits in each cycle. Previous research has shown that realistic stages are limited to radix-2 and radix-4. Higher radix dividers are therefore formed by a combination of low-radix stages. In this paper, we present an analysis of the effects of radix-2 and radix-4 SRT divider architectures and circuit families on divider area and performance. We show the performance and area results for a wide variety of divider architectures and implementations. We conclude that divider performance is only weakly sensitive to reasonable choices of architecture but significantly improved by aggressive circuit techniques.