Automatic routing method
First Claim
1. An automatic routing method for routing and designing an LSI, the method comprising the steps of:
- a) initial routing of a net;
b) removing a wire already routed if a design rule error exists in the wire or a non-routable wire is caused as a result of the initial routing; and
c) if the wire already routed and removed is a wire interconnecting a movable terminal, freely placeable within a predetermined region, to another terminal placed within a wiring region, displacing the movable terminal to a newly generated and previously unoccupied position within the predetermined region and re-routing the removed wire such that the displaced movable terminal is interconnected to the another terminal.
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Accused Products
Abstract
First, initial routing is performed on a net. If a design rule error exists in a wire already routed as a result of the initial routing, the wire already routed, causing the design rule error, is removed. Next, if the wire already routed and removed is a wire interconnecting a movable terminal, freely placeable within a predetermined region, to another terminal, then the movable terminal is displaced within the predetermined region and the removed wire is re-routed such that the displaced movable terminal is interconnected to the other terminal. Accordingly, the movable terminal can be located at an appropriate position within the predetermined region in accordance with the situation of surrounding wires. As a result, routing results of a higher density can be obtained.
165 Citations
13 Claims
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1. An automatic routing method for routing and designing an LSI, the method comprising the steps of:
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a) initial routing of a net;
b) removing a wire already routed if a design rule error exists in the wire or a non-routable wire is caused as a result of the initial routing; and
c) if the wire already routed and removed is a wire interconnecting a movable terminal, freely placeable within a predetermined region, to another terminal placed within a wiring region, displacing the movable terminal to a newly generated and previously unoccupied position within the predetermined region and re-routing the removed wire such that the displaced movable terminal is interconnected to the another terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
d) defining the predetermined region where the movable terminal is placeable; and
e) determining an initial position of the movable terminal in the defined, predetermined region.
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5. The method of claim 1, wherein in the step b), the wire already routed and to be removed is extracted by regarding the number of the movable terminals as an index of evaluation.
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6. The method of claim 1, wherein the step a) is performed without taking into consideration a design rule error caused by a wire already routed.
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7. The method of claim 1, wherein the step a) is performed without allowing a design rule error to happen with a wire already routed.
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8. A method for searching for a wiring route during automatically routing and designing an LSI in accordance with a maze algorithm in which a wiring route cost is calculated by adding a cost every time a single grid is passed in a wiring region divided into a plurality of grids,
the method comprising the steps of: -
a) inputting at least one of a height constraint and a lateral width constraint of the wiring region and hardwiring information;
b) calculating a number of available grids for each column of grids, on which the height constraint of the wiring region is applied, or each row of grids, on which the lateral width constraint of the wiring region is applied, during routing based on the hardwiring information; and
c) setting a passage cost for one of the columns of grids or one of the rows of grids, to which column or row the wiring route to be searched for proceeds, based on the number of available grids calculated for the column or the row, and adding the passage cost to the wiring route cost. - View Dependent Claims (9, 10, 11, 12, 13)
d) repeatedly searching for the wiring route if the height or lateral width constraint of the wiring region has not been satisfied after all the routes have been searched; and
e) changing the penalty for failing to satisfy the height or lateral width constraint every time the wiring route is repeatedly searched.
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13. The method of claim 12, wherein in the step e), the penalty is gradually changed from a smaller value to a larger value.
Specification