Abstract: The present invention is directed to a system and method for providing an overlap remover manager. A method for removing overlaps in a circuit design for an integrated circuit may include initiating an overlap remover manager, wherein the overlap remover manager is suitable for moving cells of an integrated circuit design to remove cell overlaps. A search for critical wires is performed and a determination is made of which violated moves of cells caused at least one critical wire. A determined violated move of the cells is rolled back and the overlap remover manager employed to remove overlaps between rolled back cells.

Abstract: The present invention includes methods for optimizing integrated circuit design by identifying a buffer tree in the integrated circuit design, the buffer tree having a plurality of vertices, each representing one of a buffer and an inverter, and also having branches, between the vertices, each representing an electrical connection. A plurality of optimization devices are applied in a random sequence to the vertices of the buffer tree. Such devices can include, for example, cell type modification; insertion of one buffer; insertion of several buffers; interchange of two grandchildren; making a grandchild into a child; making a child a grandchild; interchanging a child and a grandchild; eliminating two inverters; removing one buffer; removing more than one buffer; and removing two inverters.

Abstract: A method for selectively placing cells of an application-specific integrated circuit on a substrate surface, including the steps of defining a grid covering a substrate surface, assigning cells to the grid to provide old x and y coordinates of the cells relative to the grid, grouping the cells by function to provide functional regions within the grid, determining a density map of the surface of the substrate in all the functional regions within the grid, determining free space of the grid on the surface of the substrate relative to the density map, and assigning new cells to the free space of the grid on the substrate surface to provide an application specific integrated circuit. Use of the method provides improved layout of an integrated circuit with minimal cell congestion or overlapping.

Abstract: The present invention is a method for searching an identity base for identities that can be applied to a given formula. The method includes transforming the formulas from an identity base into a standard form, creating a set of code words for said identity base, constructing a lexicographical tree of a code word set of said identity base, and outputting a list of formula numbers from said identity base.

Abstract: A method of testing a floor plan for an integrated circuit prior to resynthesis includes attempting to construct a least-penalty path connecting pins of each long distance pin pair in the floor plan to determine whether the floor plan has an unreachable pin; and if the least-penalty path is constructed, then attempting to construct a least-penalty path connecting pins of each long distance pin pair in the floor plan to determine whether the floor plan has a bottleneck.

Abstract: Cell overlap is removed from rows during a cell placement procedure for an integrated circuit chip. The rows are partitioned into subrows so that cells in each subrow have a common characteristic vector. Cell overflow is removed from each of the subrows by moving a cell of an overflowed row or exchanging two cells, at least one of which is in the overflowed subrow. The half-cells of the dual height cells are moved to cell positions in a suitable pair of rows based on a calculated movement penalty. The movement is accomplished to align the half-cells and minimize the penalty. In preferred embodiments, the process is carried out by a computer under control of a computer program.

Abstract: A method of determining a desired connection path between a pair of points of a net separated by one or more blockages, while reducing path delays and ramp time violations and without placing buffers within any of the blockages.

Abstract: The present invention is directed to a system and method for providing an overlap remover manager. A method for removing overlaps in a circuit design for an integrated circuit may include initiating an overlap remover manager, wherein the overlap remover manager is suitable for moving cells of an integrated circuit design to remove cell overlaps. A search for critical wires is performed and a determination is made of which violated moves of cells caused at least one critical wire. A determined violated move of the cells is rolled back and the overlap remover manager employed to remove overlaps between rolled back cells.

Abstract: The present invention is directed to a system and method for providing multidirectional routing. The present invention may provide an arbitrary number of routing layers and an arbitrary direction on each of those layers to provide a smaller die size and to reduce power consumption by providing more flexibility for net routing directions.

Abstract: The present invention comprises method for optimizing an integrated circuit design that includes computing of capacities and delays of an integrated circuit design, resynthesizing said integrated circuit design utilizing a plurality of local optimization procedures, and removing overlap the local optimization procedures can include a local resynthesis of logic trees procedure that utilizes multiple cost functions, a dynamic buffer and inverter tree optimization procedure, and a cell resizing procedure. Generally, faster local optimization procedures are applied first and slower, more thorough procedures are applied to areas where the faster procedures have not solved the optimization tasks.

Abstract: A method of computing timing delays of timing edges of a path of an integrated circuit design. According to the method, all pins within the path are identified, and all timing edges defined by the pins within the path are identified. All pins within the path that are a leading pin of one of the time edge in the path are also identified. For each given pin within the path, a tabulation is made of a number of pins that are upstream from the given pin along a contiguous series of the timing edges in the path. A computational rank is assigned to the given pin based upon the tabulated number for the given pin. The timing edges are ordered for computation based upon the computational rank of the leading pin of each timing edge in the path, to produce an ordered list of timing edges. The timing delays of the timing edges of the path are computed according to the ordered list of timing edges.

Abstract: A method of synthesizing a clock tree for an integrated circuit design is disclosed that includes the steps of constructing an initial balanced clock tree for an integrated circuit design; calculating a clock arrival time for each clock driven cell in the initial clock tree; performing a timing analysis from the clock arrival time calculated for each clock driven cell; and performing a skew optimization concurrently with the timing analysis to correct timing violations discovered by the timing analysis.

Abstract: Clock delays are changed in a clock network of an ASIC. Global skew optimization is achieved by restructuring a clock domain to balance clock delays in the domain, and by equalizing clock delays of several domains of a group that have timing paths between them. Clock delays are equalized using buffer chains affecting all leaves of the respective domain, and an additional delay coefficient that equalizes clock delay. The clock insertion delays are changed for each group by restructuring the buffers in the group, based on both the data and clock logics to optimize the paths. Local skew optimization is achieved by restructuring the clock domain using a heuristic algorithm and re-ordering the buffers of the domain. A computer program enables a processor to carry out the processes.

Abstract: Provided are systems and techniques for optimizing an integrated circuit design, in which a critical zone is identified in an integrated circuit design and a plurality of alternative identities are applied in the critical zone in order to obtain a corresponding plurality of outcomes. Alternative representations are then identified as those of the plurality of outcomes pursuant to which at least one of ramptime and timing are improved, and a best one of the alternative representations is selected to replace into the critical zone based on specified priorities which include: (i) selecting based on reduction in ramptime violation; (ii) selecting from among alternative representations that preserve cell area based on timing improvement; and (iii) if all alternative representations increase cell area, selecting based on an evaluation of a relationship between timing decrement and area increment.

Abstract: The present invention selects parts of an integrated circuit description for resynthesis and then prepares those parts for resynthesis. Initially, a resynthesis goal is input, with the resynthesis goal having been selected from a set of possible resynthesis goals. Plural buffer and/or logic trees in the integrated circuit description are then selected based on the resynthesis goal, and information for each of the selected trees is obtained and stored. The tree information includes: (i) a description of each tree cell, including cell types, cell coordinates, and flips and angles of the tree cell, (ii) a description of each input net, (iii) a signal arrival time for each input net as a function of a capacity of such input net, (iv) coordinates of each pin driving each input net, and (v) a maximum capacity of each input net that will prevent such input net from having a timing violation.

Abstract: An optimizing method for integrated circuits wherein coordinates are assigned to cells of a logic tree in a manner that maintains desirable cell density characteristics.

Abstract: A method for resynthesizing a design of an integrated circuit using a parallel processing mode. A single processing mode is entered by activating a main thread and locking a semaphore associated with the main thread. The design of the integrated circuit is resynthesized using the main thread. Tasks to be accomplished in the parallel processing mode are identified. The semaphore associated with the main thread is unlocked, and the operation of the single processing mode is ceased. Ordinal threads are activated by unlocking a semaphore associated with each ordinal thread. The tasks are processed in parallel by assigning the tasks to the ordinal threads and the main thread. Upon completion of one of the assigned tasks by one of the ordinal threads, it is determined whether an additional task remains to be assigned. In the case where the additional task remains, the additional task is assigned to the completed one of the ordinal threads.

Abstract: A method for resynthesizing a design of an integrated circuit using a parallel processing mode. A single processing mode is entered by activating a main thread and locking a semaphore associated with the main thread. The design of the integrated circuit is resynthesized using the main thread. Tasks to be accomplished in the parallel processing mode are identified. The semaphore associated with the main thread is unlocked, and the operation of the single processing mode is ceased. Ordinal threads are activated by unlocking a semaphore associated with each ordinal thread. The tasks are processed in parallel by assigning the tasks to the ordinal threads and the main thread. Upon completion of one of the assigned tasks by one of the ordinal threads, it is determined whether an additional task remains to be assigned. In the case where the additional task remains, the additional task is assigned to the completed one of the ordinal threads.

Abstract: A method for routing nets in an integrated circuit design, said method comprising the steps of dividing the integrated circuit design with lines in a first direction and lines in a second direction, forming a routing graph having vertices and edges, wherein vertices correspond to locations where lines in the first direction cross lines in the second direction, routing nets as a function of said routing graph with parallel processors operating substantially simultaneously, determining the relative wire congestion among different areas in the integrated circuit design, and rerouting nets passing though areas with a relatively high wire congestion.

Abstract: A method for routing nets in an integrated circuit design, said method comprising the steps of dividing the integrated circuit design with lines in a first direction and lines in a second direction, forming a routing graph having vertices and edges, wherein vertices correspond to locations where lines in the first direction cross lines in the second direction, routing nets as a function of said routing graph with parallel processors operating substantially simultaneously, determining the relative wire congestion among different areas in the integrated circuit design, and rerouting nets passing though areas with a relatively high wire congestion.