Optimizing designs containing black boxes

Question

1. What are the contributions mentioned in the paper "Optimizing designs containing black boxes" ?

2. What is the definition of a complex combinational design?

3. What is the current approach to synthesis?

4. What is the way to synthesize a complex combinational design?

Accepted Answer

Using this notion, the authors describe a sound and complete methodology for optimizing such designs.

Accepted Answer

In particular, the notion of “don’t cares” sets, i.e., inputs for which a gate can output any value carries over from logic synthesis on simple combinational networks [10]; the same is true of “compatible sets of permissible functions” [4, 11] is useful.

Accepted Answer

In the past, the approach taken for synthesis as well as verification of designs with black boxes has been to make the inputs to the black boxes primary outputs, and output of the black boxes primary inputs.

Accepted Answer

designs with black boxes have been synthesized by making the inputs to the black boxes primary outputs, and output of the black boxes primary inputs, and synthesizing the simple logic [5, 1].

Accepted Answer

The concept of redundancy removal can be extended to complex combinational netlists:Definition 4 A gate is stuck-at-1(0) redundant in a combinational complex netlist when it can be replaced by a gate taking the constant value 1(0) and the resulting netlist is equivalent to the original netlist, where the notion of equivalence is that for complex combinational netlists, as given in Definition 2.

Accepted Answer

The authors then formed the consistency network, computed the compatible observability don’t cares for the gates as described in Section 4.2.1, and simplified the functions for the gates using these don’t cares [2].

Accepted Answer

The following theorem (the proof of which is given in [7]) demonstrates that the authors can perform redundancy removal on the simple logic associated with D by performing redundancy removal on the nodes corresponding to D in the consistency network.

Accepted Answer

All this was relatively simple to achieve, since the authors were able to use the existing code for the full simplify command in SIS which computes compatible observability don’t cares; the authors simply restricted the nodes chosen to be simplified in the consistency network to be from D and not from Ddup or the consistency logic.

Accepted Answer

D0 D1Figure 1: Plug-in plug-out replaceability.as a combinational netlist if no latches occur in it; otherwise, it will be referred to as a sequential netlist.

Accepted Answer

These black boxes can arise in many ways:1. In hierarchical synthesis, components are recursively optimized from the “bottom-up” and then treated as fixed blocks.

Accepted Answer

Step 3: For each pair of primary inputs in DSIMP which correspond to black boxes of the same variety in DPM, add to DSIMP a “consistency” gate, which outputs 1 exactly when the pair of primary inputs have the same value or the inputs to the corresponding black boxes from DPM take distinct values.

Optimizing designs containing black boxes

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Most frequently asked questions

1. What are the contributions mentioned in the paper "Optimizing designs containing black boxes" ?

2. What is the definition of a complex combinational design?

3. What is the current approach to synthesis?

4. What is the way to synthesize a complex combinational design?

5. What is the concept of redundancy removal?

6. What did the authors do to simplify the functions for the gates?

7. What is the proof of the theorem?

8. What was the procedure used to achieve?

9. What is the meaning of a netlist?

10. What is the common way to synthesize components with black boxes?

11. What is the difference between the two?

Figures

Citations

Intellectual property protection by watermarking combinational logic synthesis solutions

Bit-Level Abstraction in the Verfication of Pipelined Microprocessors by Correspondence Checking

Verification of Designs Containing Black Boxes.

Verification of designs containing black boxes

Don't Care Computation in Minimizing Extended Finite State Machines with Presburger Arithmetic.

References

Introduction to Automata Theory, Languages, and Computation

Graph-Based Algorithms for Boolean Function Manipulation

Synthesis and optimization of digital circuits

Logic Minimization Algorithms for VLSI Synthesis

A Practical Decision Procedure for Arithmetic with Function Symbols

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