As will be appreciated by those skilled in the art, a large-scale integrated circuit design is often used over and over again to implement different functional designs. This repeated use results in a large number (often thousands) of elements in the integrated circuit design that are not used for a specific functional design. These elements unused in a particular design are connected directly to a power signal, logical “1” or logical “0” and are referred to as being tied up (connected to logical one/vdd) or tied down (connected to logical 0/gnd).
In the prior art, unedited tie net data is used by the router to route the connections of an unused element to the power grid. This unedited tie net data lumps unused elements in single large tie net. Although these connections are not timing critical, and thus the respective routing paths for these connections is not critical, routing programs have difficulty in routing the tie net data as presented to the router in the prior art due to the massively parallel nature of the problem seen by the router in routing the tie net. A routing problem that is massively parallel can cause the router to come up with sub-optimal solutions and take a long time to complete.
USPTO Backgrounds
USPTO Backgrounds