Abstract: This invention recognizes the ability of logic optimization to help placement relieve congestion. Different types of logic optimizations are used to help placement relieve congestion. In one type of optimization, the speed of parts of the circuit is improved by selecting faster cells. In another type of optimization, the topology of the circuit is changed such that placement can now move cells, which could not have been moved before, to reduce congestion and thus enable routing. A distinguishing feature of this methodology is that it not only uses the placement information for interconnection delay/area estimates during logic optimization, but also uses logic optimization to aid the physical placement steps by providing support to placement so that the congestion of the circuit is improved. The aim is to avoid getting into a situation where the placed circuit cannot be routed.

Abstract: A large number of possible cell placements for an integrated circuit chip are evaluated to determine which has the highest fitness in accordance with a predetermined criteria such as interconnect congestion. Each cell placement, which constitutes an individual permutation of cells from a population of possible permutations, is represented as an initial cell placement in combination with a list of individual cell transpositions or swaps by which the cell placement can be derived from the initial cell placement. A cell placement can be genetically mutated and/or inverted by adding swaps to the list for its cell placement which designates cells to be transposed. Genetic crossover can be performed by transposing swaps between the lists for two cell placements. This cell representation and transposition method enables any type of cell transposition to be performed without loss or duplication of cells or generation of illegal placements.

Abstract: A subscriber station for decrypting and decompressing data is provided on a single chip. The chip includes a DES decryption unit for performing decryption of incoming data with a DES key, a public key decryption unit for decrypting the DES key, a general purpose microprocessor for performing decompression, and a Secure Buffer for protecting the decrypted data prior to decompression. The chip includes an embedded key for the public key decryption unit and a bus for providing a data communication path between the microprocessor and the decryption units.

Abstract: A method for optimizing layout design using logical and physical information performs placement, logic optimization and routing and routing estimates concurrently. In one embodiment, circuit elements of the integrated circuit is partitioned into clusters. The clusters are then placed and routed by iterating over an inner-loop and an outer-loop according to cost functions in the placement model which takes into consideration interconnect wiring delays. Iterating over the inner-loop, logic optimization steps improves the cost functions of the layout design. Iterating over the outer-loop, the size of the clusters, hence the granularity of the placement, is refined until the level of individual cells is reached. The present method is especially suited for parallel processing by multiple central processing units accessing a shared memory containing the design data base.

Abstract: A system for providing information to memory within a local device is provided herein. The system initially receives information transmitted from a remote location and reads predetermined data, including start and end addresses, within the local device. The system computes a checksum based on information received from the remote location and the predetermined data and compares a predetermined checksum to the received information checksum. If the predetermined checksum does not equal the received information checksum, the system requests retransmission of information and repeats the preceding steps (receiving information, computing a checksum, and comparing) until the predetermined checksum equals the received information checksum. The system then provides the valid information to local device memory. The invention may execute a protocol to receive information packets and store the information packets in appropriate memory locations after receiving the information.

Abstract: The capacity of a cache memory is substantially reduced over that required for a multi-chip distributed shared memory (DSM) implementation to enable the cache memory, a main memory, a processor and requisite logic and control circuitry to fit on a single integrated circuit chip. The increased cache miss rate created by the reduced cache memory capacity is compensated for by the reduced cache miss resolution period resulting from integrating the main memory and processor on the single chip. The reduced cache miss resolution period enables the processor clock rate to be substantially increased, so that a processor having a simple functionality such as a reduced instruction set computer (RISC) processor can be utilized and still provide the required processing speed.

Abstract: A cell placement for an integrated circuit chip comprises a large number of cells allocated to respective locations on the surface of the chip. The placement is divided into switch boxes that surround the cell locations respectively. A bounding box is constructed around each net of a netlist for the placement. A congestion factor is computed for each switch box as being equal to the number of bounding boxes that overlap the respective switch box. A cost factor for the placement and associated netlist is computed as the maximum value, average value, sum of squares or other function of the congestion factors. The individual congestion factor computation can be modified to require that a pin of a net of one of the bounding boxes overlap or be within a predetermined distance of a switch box in order for the congestion factor to be computed as the sum of the overlapping bounding boxes in order to localize and increase the accuracy of the cost factor estimation.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.

Abstract: An initial placement of cells for an integrated circuit chip is decomposed into a hierarchial order of groups of cells. The groups are routed simultaneously using parallel processors, and the results are recomposed to provide a global routing that provides a detailed mapping of cell interconnect congestion in the placement. Areas of high congestion are identified, and a congestion reduction algorithm is applied using the parallel processors to alter the placement in these areas simultaneously. The overall fitness of the placement is then computed, and if it has not attained a predetermined value, the steps of identifying congested areas and applying the congestion reduction algorithm to these areas are repeated. The cumulative error created by altering the placement without repeating the global routing is estimated, and if it exceeds a predetermined value, the global routing is also repeated.

Abstract: One or more non-overlapping moving windows are positioned over a placement of cells for an integrated circuit chip to delineate respective subsets of cells. A fitness improvement operation such as simulated evolution is performed on the subsets simultaneously using parallel processors. The windows are either moved to specifically identified high interconnect congestion areas of the placement, or are moved across the placement in a raster type pattern such that each area of the placement is processed at least once. Exchange of misplaced cells between subsets can be accomplished by dimensioning the windows and designing the window movement pattern such that the subsets overlap. Alternatively, such exchange can be accomplished by using two sets of windows of different sizes. As yet another alternative, the improvement operation can allow misplaced cells to move to a border area outside a window.

Abstract: An information system and method for reducing workload load on servers in an information system network. The system defines a group of interconnected clients which have associated cache memories. The system maintains a shared group cache look-up table for the group having entries which identify data items cached by the clients within the group and identify the clients at which the data items are cached. Each client in the group has access to the group cache look-up table, and any client or group can cache any data item. The system can include a hierarchy of groups, with each group having a group cache look-up table. The group cache look-up tables minimize requests for data items outside the groups and greatly minimize the service load on servers having popular data items.

Abstract: A digital computer includes a processor, a memory and a program which operate in combination for inputting a placement of cells for an integrated circuit chip, and a netlist of wiring nets interconnecting the cells. The placement is divided into a plurality of contiguous regions, and cell densities in the regions are computed in accordance with locations of the cells in the placement. Wiring densities in the regions are computed in accordance with the locations of the cells and the netlist. The shapes of the regions are altered to produce altered regions such that cell densities and wiring densities in the altered regions are more level or uniform. The placement is then altered such that the cells occupy locations in the altered regions which are relative to their locations in the original regions. The porosities of the cells can also be computed and used in the computation of the region shapes.

Abstract: A physical design automation system for producing a highest fitness cell placement for an integrated circuit chip includes a decomposition/recomposition processor for decomposing a cell placement optimization process into a plurality of tasks and recomposing the highest fitness cell placement from results of performing the tasks. A plurality of worker processors independently perform the tasks and produce results. A host processor distributively assigns the tasks to the worker processors in response to work requests received therefrom. Each worker processor sends a work request to the host processor after completing a task. The host processor maintains a list of unassigned tasks, assigned tasks and completed tasks, and revises the list to redesignate assigned tasks as unassigned tasks upon determining that the list includes no unassigned tasks and at least one assigned task, thus making the system immune to the failure of one or more processors.

Abstract: A large number of possible placements of cells on an integrated circuit chip are generated and evaluated to determine the placement with the highest fitness. Cells for transposition or "swapping" within each placement using genetic algorithms are selected using greedy algorithms based on the fitness of each cell. The cell fitnesses are evaluated in terms of interconnect congestion, total net wire length or other criteria. Cells are selected for genetic crossover by sorting the cells in order of fitness and multiplying the cell fitnesses by weighting factors that increase non-linearly with rank. The cells are selected using linear random number generation such that cells with higher fitnesses have a higher probability of selection. Cells having lowest fitness are selected for mutation, and transposed to random locations, to adjacent locations, with cells having second worst fitness, to the center of mass of the respective interconnect nets, or with two or more cells in a cyclical manner.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.

Abstract: A plurality of processors which can be the same or different are formed on a single integrated circuit chip together with a memory controller and an I/O controller, and are interconnected by a data transfer bus. The processors can have larger word lengths and operate at higher speeds than comparable single chip processors due to reduced latency and signal path lengths. The processors are further interconnected by a processor synchronization bus which enables one processor to cause another processor to perform a task by generating an interrupt and passing the required parameters. The parameters can be passed via shared memory, or via a bidirectional data section of the processor synchronization bus. A processor running a large scale CAD or similar application can cause a smaller processor to perform I/O tasks in native code.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.

Abstract: The fitness of a cell placement for an integrated circuit chip is optimized by relocating at least some of cells to new locations that provide lower interconnect congestion. For each cell, the centroid of the net of cells to which the cell is connected is computed. The cell is then moved toward the centroid by a distance that is equal to the distance from the current position of the cell to the centroid multiplied by a "chaos" factor .lambda.. The value of .lambda. is selected such that the cell relocation operations will cause the placement to converge toward an optimal configuration without chaotic diversion, but with a sufficiently high chaotic element to prevent the optimization operation from becoming stuck at local fitness maxima. The new cell locations can be modified to include the effects of cells in other locations, such as by incorporating a function of cell density gradient or force direction into the computation.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.