An algorithm to determine mutually exclusive operations in behavioral descriptions

Abstract

Scheduling and binding are two major tasks in architectural synthesis from behavioral descriptions. The information about the mutually exclusive pairs of operations is very useful in reducing both the total delay of the schedule and the resource usage in the final circuit implementation. In this paper, we present an algorithm to identify the largest set of mutually exclusive operation pairs in behavioral descriptions. Our algorithm uses data-flow analysis on a tabular model of system functionality, and is shown to work better than the existing methods for identifying mutually exclusive operations.Interconnect Tuning Strategies for High-Performance Ics83590471abs.htm _Andrew B. Kahng, Sudhakar Muddu, Egino Sarto and Rahul SharmaSilicon Graphics, Inc.Interconnect tuning is an increasingly critical degree of freedom in the physical design of high-performance VLSI systems. By interconnect tuning, we refer to the selection of line thicknesses, widths and spacings in multi-layer interconnect to simultaneously optimize signal distribution, signal performance, signal integrity, and interconnect manufacturability and reliability. This is a key activity in most leading-edge design projects, but has received little attention in the literature. Our work provides the first technology-specific studies of interconnect tuning in the literature. We center on global wiring layers and interconnect tuning issues related to bus routing, repeater insertion, and choice of shielding/spacing rules for signal integrity and performance. We ad-dress four basic questions. (1) How should width and spacing be allocated to maximize performance for a given line pitch? (2) For a given line pitch, what criteria affect the optimal interval at which repeaters should be inserted into global interconnects? (3) Under what circumstances are shield wires the optimum technique for improving interconnect performance? (4) In global interconnect with repeaters, what other interconnect tuning is possible? Our study of question (4) demonstrates a new approach of offsetting repeater placements that can reduce worst-case cross-chip delays by over 30% in current technologies.