Method of estimating wire length including correction and summation of estimated wire length of every pin pair
First Claim
1. A method of estimating wire length, comprising the steps of:
- defining a net on a semiconductor integrated circuit and extracting pin pairs from said net, said pin pairs represented by an edge between any pair of nodes of a complete graph in which macro cells on the net serve as nodes;
estimating wire length of each of said pin pairs; and
estimating wire length of said net based on the estimated wire length of each of said pin pairs;
whereinsaid step of estimating the estimated wire length of each pin pair includes the steps ofextracting a subcircuit satisfying a prescribed relation with a pin pair which is an object of processing, andestimating wire length of said object pin pair based on a characteristic of said subcircuit.
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Abstract
In a method of estimating wire length allowing highly precise estimation of the estimated wire length of a net, an object net is selected. Thereafter, the object net is developed into pin pairs. For each of the pin pairs, a subcircuit satisfying a prescribed relation with the pin pair is extracted from the semiconductor integrated circuit. From the subcircuit, information necessary for estimating wire length of the pin pair (number of nets in the subcircuit and total area of macro cells in the subcircuit) is extracted. Based on the extracted information of the subcircuit, estimated wire length of the pin pair is estimated. Based on the estimated wire length of the pin pair, estimated wire length of the object net is estimated.
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Citations
11 Claims
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1. A method of estimating wire length, comprising the steps of:
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defining a net on a semiconductor integrated circuit and extracting pin pairs from said net, said pin pairs represented by an edge between any pair of nodes of a complete graph in which macro cells on the net serve as nodes; estimating wire length of each of said pin pairs; and estimating wire length of said net based on the estimated wire length of each of said pin pairs;
whereinsaid step of estimating the estimated wire length of each pin pair includes the steps of extracting a subcircuit satisfying a prescribed relation with a pin pair which is an object of processing, and estimating wire length of said object pin pair based on a characteristic of said subcircuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for estimating wire length on a semiconductor integrated circuit, comprising the steps of:
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selecting an object net of which wire length is to be estimated, the object net including a plurality of macro cells and at least one wire interconnecting said macro cells; extracting at least one pin pair from said object net, wherein each pin pair represents an edge between nodes of a complete graph derived from said macro cells which serve as nodes of the complete graph; selecting an object pin pair from said object net; extracting all macro cells externally connected by said pin pairs to said first and second macro cells; classifying said extracted macro cells included in said subcircuit as already-searched macro cells, and said extract macro cells not included in said subcircuit as not-yet-searched macro cells; comparing a first number of said already-searched macro cells and a second number of not-yet-searched macro cells, and determining said object pin pair and two macro cells connected thereto as a subcircuit if said first number is larger than said second number and completing the process, otherwise returning to said object pin selecting step to select another pin pair from said net.
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Specification