Improving functional density through run-time constant propagation

ABSTRACT

Circuit specialization techniques such as constant propagation are commonly used to reduce both the hardware resources and cycle time of digital circuits. When reconfigurable FPGAs are used, these advantages can be extended by dynamically specializing circuits using run-time reconfiguration (RTR). For systems exploiting constant propagation, hardware resources can be reduced by folding constants within the circuit and dynamically changing the constants using circuit reconfiguration. To measure the benefits of circuit specialization, a functional density metric is presented. This metric allows the analysis of both static and run-time reconfigured circuits by including the cost of circuit reconfiguration. This metric will be used to justify runtime constant propagation as well as analyze the effects of reconfiguration time on run-time reconfigured systems.

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.1 Types and Design Styles
          Subjects: Gate arrays

Additional Classification:
  B. Hardware
  B.5 REGISTER-TRANSFER-LEVEL IMPLEMENTATION
      B.5.1 Design
          Subjects: Arithmetic and logic units

General Terms:
Algorithms, Design, Measurement, Performance