Automatic layout design method of wirings in integrated circuit using hierarchical algorithm
First Claim
1. A method for automatically wiring a circuit by dividing a region into a plurality of coarse global grids and by dividing cut-lines which are inserted and set on boundaries of the global grids and are crossed by a wiring net, the method, according to a hierarchical processing used for a computer-aided design system, comprising the steps of:
- setting up and calculating an evaluation function having therein a plurality of evaluation terms for indicating selectability by which the cut-line is preferentially selected so that a wiring congestion is most relaxed;
giving weights to the respective plurality of evaluation terms and defining an evaluation function which totals the plurality of the evaluation terms, wherein the evaluation terms includea first evaluation term which is weighted such that a cut-line is more likely to be selected when a shape of the divided regions is close to a square; and
a second evaluation term which is weighted such that a cut-line having a most congested wiring is likely to be selected, based on a number of nets crossing the cut-line and a number of wirings capable of passing therethrough;
dividing the region into two by a cut-line having a minimum value of the evaluation function;
determining a position to cross all nets crossing the cut-line; and
performing the above steps recursively and hierarchically until the divided regions become a predetermined minimum size.
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Abstract
A method, according to a hierarchical processing used for a computer-aided design system, for automatically wiring a circuit by dividing a region into a plurality of coarse global grids. The automatic wiring method includes the steps of: setting up and calculating an evaluation function having therein a plurality of evaluation terms for indicating selectability by which the cut-line is preferentially selected so that a wiring congestion is most relaxed; giving weights to the respective plurality of evaluation terms and defining an evaluation function which totals the plurality of the evaluation terms; dividing the region into two by a cut-line having a minimum value in the evaluation functions; determining a position to cross all nets crossing the cut-line; and performing the above steps recursively and hierarchically until the divided regions become a predetermined minimum size.
91 Citations
6 Claims
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1. A method for automatically wiring a circuit by dividing a region into a plurality of coarse global grids and by dividing cut-lines which are inserted and set on boundaries of the global grids and are crossed by a wiring net, the method, according to a hierarchical processing used for a computer-aided design system, comprising the steps of:
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setting up and calculating an evaluation function having therein a plurality of evaluation terms for indicating selectability by which the cut-line is preferentially selected so that a wiring congestion is most relaxed; giving weights to the respective plurality of evaluation terms and defining an evaluation function which totals the plurality of the evaluation terms, wherein the evaluation terms include a first evaluation term which is weighted such that a cut-line is more likely to be selected when a shape of the divided regions is close to a square; and a second evaluation term which is weighted such that a cut-line having a most congested wiring is likely to be selected, based on a number of nets crossing the cut-line and a number of wirings capable of passing therethrough; dividing the region into two by a cut-line having a minimum value of the evaluation function; determining a position to cross all nets crossing the cut-line; and performing the above steps recursively and hierarchically until the divided regions become a predetermined minimum size. - View Dependent Claims (2, 3, 4, 5)
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6. A method for automatically wiring a circuit containing a macro-block, the circuit comprising first and second layers for wiring, wiring being prohibited in the macro-block on the first layer, by dividing by a cut-line a region having the macro-block into a plurality of coarse global grids and by dividing the circuit by cut-lines which are inserted and set on boundaries of the global grids and are crossed by a wiring net, the method, according to a hierarchical processing used for a computer-aided design system, comprising the steps of:
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generating a segment passing from an end to another end of the macro-block on a net which involves the cut-lines crossing the macro-block when wiring in the macro-block on the second layer is permitted; regarding both ends of the generated segment as pseudo terminals; and performing the above steps recursively and hierarchically until the divided regions become a predetermined minimum size.
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Specification