Behavior-level observability don't-cares and application to low-power behavioral synthesis

Many techniques for power management employed in advanced RTL synthesis tools rely explicitly or implicitly on observability don’t-care (ODC) conditions. In this paper we present a systematic approach to maximizing the effectiveness of these techniques by generating power-friendly RTL descriptions in a behavioral synthesis tool. We first introduce the concept of behavior-level observability and investigate its relation with observability under a given schedule, using an extension of Boolean algebra. We then propose an efficient algorithm to compute behavior-level observability on a data-flow graph. Our algorithm exploits knowledge about select and Boolean instructions, and allows certain forms of other knowledge, once uncovered, to be considered for stronger observability conditions. We also describe a behavioral synthesis flow where behavior-level observability is used to guide the scheduler toward maximizing the likelihood that execution of power-hungry instructions will be av...

• Type: Conference
• Year: 2009
• Where: ISLPED
• Authors: Jason Cong, Bin Liu, Zhiru Zhang
• Keywords: Behavior-level Observability, Behavioral Synthesis, Hardware, ISLPED 2009, Synthesis Tool