Abstract: A system and method are disclosed for legalizing a flat or hierarchical VLSI layout to meet multiple grid constraints and conventional ground rules. Given a set of ground rules with multiple grid constraints and a VLSI layout (either hierarchical or flat) which is layout-versus-schematic (LVS) correct but may not be ground rule correct, the system and method provide a legalized layout which meets the multiple grid constraints while maintaining LVS correctness and fixing the ground rule errors as much as possible with minimum layout perturbation from the input design. The system and method support multiple grid pitch constraints for hierarchical design, and provide for LVS correctness to be maintained while an on-grid solution possibly with some spacing violations.

Abstract: Various approaches for embedding a hardware object in an event-driven simulator are disclosed. The various approaches involve generating an HDL proxy component having an HDL definition of each port of the hardware object and respective event handler functions associated with input ports of the HDL proxy component. The event handler functions are responsive to simulation events appearing on the input ports. A configuration bitstream is generated for implementing the hardware object on a programmable logic circuit, and a first object is generated to contain configuration parameter values indicating characteristics of the ports and a location of the configuration bitstream. A second object is generated and is configured to initiate configuration of the programmable logic circuit with the configuration bitstream. The second object further provides input data to and receives output data from the programmable logic circuit.

Abstract: The present invention is a system and method for statistical or probabilistic static timing analysis of digital circuits, taking into account statistical delay variations. The delay of each gate or wire is assumed to consist of a nominal portion, a correlated random portion that is parameterized by each of the sources of variation and an independent random portion. Arrival times and required arrival times are propagated as parameterized random variables while taking correlations into account. Both early mode and late mode timing are included; both combinational and sequential circuits are handled; static CMOS as well as dynamic logic families are accommodated. The timing analysis complexity is linear in the size of the graph and the number of sources of variation. The result is a timing report in which all timing quantities such as arrival times and slacks are reported as probability distributions in a parameterized form.

Abstract: A method is provided for simulating a complex system including a scheduler hierarchy. The complex system includes at least one processor that executes a set of functions under the control of a hierarchical group of schedulers. The method includes a step of constructing an architectural model of the complex system comprising a hierarchical group of components, each of said components comprising an instance of an object class belonging to the group containing: a first class, known as the Processor class, which represents an abstract model of any processor included in the complex system, a second class, known as the Function class, which represents an abstract model of any function executed by the complex system; and a third class, known as the Scheduler class, which represents an abstract model of any scheduler. Each instance is initialised with at least one attribute that characterises the behaviour desired therefrom.

Abstract: A design structure for a Booth decoder is provided. The Booth decoder may comprise three circuits that run in parallel. A first circuit is used to generate a shift control signal output. A second circuit is used to generate a zero control signal output. A third circuit is used to generate an invert control signal output. The first and second circuits receive the three-bit block as an input and generate their respective outputs based on the setting of each of the bits. The third circuit receives only the most significant bit of the three-bit block as its input and generates an invert signal output based on the setting of the most significant bit. In each of these circuits, the number of complex gates and transistors is minimized thereby reducing gate delay and power consumption in generating the control signals for performing a Booth multiplication operation.

Abstract: A simulation system includes glitch injection circuitry in one or more hardware design units to allow the injection of glitches or noise to evaluate the system's response to errors on signals between the hardware design units. The simulation system includes a stimulation module with a set of drivers to input simulation patterns into the design units. Some inputs to software models are driven by the outputs of software models of another design unit. The stimulation module can monitor these signals driven by the software model but it is difficult for the stimulation module to directly drive these signals. The added glitch circuitry allows injection of errors into the simulated hardware by the stimulation module on signals that are not directly driven by the stimulation module but are driven by the outputs of hardware design units.

Abstract: A system for interfacing hardware emulation to software simulation environments may include a simulation node configured to simulate a first portion of a system under test and a hardware emulation node configured to emulate a second portion of the system under test. The hardware emulation node may also be configured to exchange simulation information (such as representations of signal values obtained as output from the emulated portion of the system under test) with the simulation node. The hardware emulation node may contain a field programmable gate array devices (FPGA) configured to perform the hardware emulation. The FPGA may be mounted on an expansion board, such as a PCI (Peripheral Component Interconnect) board.

Abstract: A method of analyzing a circuit simulation comprising pruning a signal flow graph. Pruning the signal flow graph includes selecting a current vertex from a multiple input vertices in the signal flow graph. Each one of the input vertices is connected to a primary input of the signal flow graph. Determining if the current vertex includes at least one of a sensitivity parameter or a sensitivity variable. If the current vertex includes at least one of a sensitivity parameter or a sensitivity variable then the current vertex is identified as being part of a sensitivity path and is added to a first sub-group of vertices. Pruning the signal flow graph also includes determining if any remaining non-visited neighbor vertices remain to be analyzed. If any remaining non-visited neighbor vertices remain to be analyzed then selecting a neighboring vertex and determining if the selected neighbor vertex is identified as a sensitivity path.

Abstract: A simulation executing unit 1, an execution list forming unit 2, and an execution list 3 are prepared. The simulation executing unit 1 does not execute all of function models 4 every cycle, but executes only such a process operation described in the execution list 3 formed by the execution list forming unit 2. Upon receipt of notification as to a status change sent from each of hardware, the execution list forming unit 2 dynamically forms the execution list 3 of process operations which are executed every cycle in conjunction with the status change. As a result, the simulation executing unit 1 performs such a process operation suitable for the status change every cycle so as to perform a simulation in a high speed.

Abstract: An equivalency testing system, for formally comparing an RTLM and HLM, is presented. RTLM and HLM are first converted into DFGs RTLMDFG and HLMDFG. RTLMDFG and HLMDFG are then put into timestep form and are called RTLMts and HLMts. A test bench CSts is selected that couples RTLMts and HLMts. The combination of RTLMts[t], HLMts [t] and CSts[t] can have parts designated as datapath. Parts designated as datapath can be subject to a form of equivalence checking that seeks to prove equivalence by a form of inductive theorem proving that propagates symbolic values indicative of whether a node carries the same data content as another node. The theorem proving starts from initial conditions for HLMts [t] determined by partial execution of the HLM. Propagation to a combinational function output can be determined from equivalence relationships between it and another combinational function. Propagation through a multiplexer can produce a conditional symbolic value.

Abstract: Disclosed are techniques for simulating a multiprocessor system is disclosed. Aspects of the present invention are based on such an observation that most memory accesses from different simulated processors do not conflict, and therefore the conservative policy for performing synchronization of all the memory accesses can waste a large amount of processing time. By identifying possibly conflicting memory accesses and only performing synchronization of these memory accesses, the synchronization cost can be reduced considerably. Since the function simulator is able to operate faster and to perform the same memory accesses, the possibly conflicting memory accesses can be identified by first executing the function simulator.

Abstract: A method of verifying the power off effect of a design entity of a digital system includes a device model, a test input signal model, and a test output signal model specified in a hardware design language, at a register transfer level (RTL). The device model describes function blocks for performing predetermined functions using a plurality of power sources. The device model includes a model for a case where all of the power sources are supplied and a model for a case where one or more of the power sources are blocked. The test input signal model describes a test input signal to be input to the device model to verify the case where all of the power sources are supplied and the case where one or more of the power sources are blocked. The test output signal model describes a test output signal to be output from the device model in response to the test input signal.

Abstract: Clock gating analysis of a target circuit having a plurality of clock gates, involves the calculation of a clock gate function for each of the clock gates. The clock gate functions indicate an activation state of the clock gates and a combination of output values from sequential circuit elements in the target circuit are substituted into each of the clock gate functions to obtained clock gate function values. Combinations of the clock gate function values form individual clock gating states. Each clock gating state indicates an activation state of each of the local clocks, collectively. A table indicating correlations between the combinations of output values and the clock gating states is generated and from the conversion table, a group that includes all of the clock gating states possible is output.

Abstract: According to a method of simulation processing, a simulation model is received that includes a plurality of design entity instances modeling a digital system and one or more instrumentation entity instances, separate from the plurality of design entity instances, that generate instances of instrumentation events for testing purposes during simulation. In response to receiving an exclusion list identifying at least one instance of one or more instrumentation events to be removed from the simulation model, at least one instance of the one or more instrumentation events and associated logic elements are removed from the one or more instrumentation entity instances of the simulation model prior to simulation, such that a more compact simulation model is obtained.

Abstract: A method for determining an allowable simultaneous switching output level on a bank-by-bank basis is described. An inductance scaling factor is determined for a first bank. A noise limit scaling factor is determined for the first bank. A bounce voltage scaling factor is determined for the first bank. The inductance scaling factor, the noise limit scaling factor, and the bounce voltage scaling factor are multiplied with one another to provide the simultaneous switching output level for the first bank.

Abstract: Sequential digital integrated circuits have stable state nodes that are capable of retaining their state (logic value) even in the absence of any input directly driving these points. However, in addition to stable state nodes, some custom-designed digital circuits have so-called transient state nodes. A transient state node is defined as node that can directly affect the value of a stable state node and is combinatorially driven by inputs of the circuit, but the transition delay from at least one input to the node is greater than a predefined threshold value. Identifying such transient state nodes, along with the stable state nodes, is critical for the efficient simulation of custom digital circuits by a hierarchical device level digital simulator. A method is provided herein for identifying transient state nodes in a digital circuit, given the circuit's netlist and the identity of the stable state nodes in the circuit.

Abstract: A method is disclosed of associating a mapping function with a configuration construct of a digital design defined by one or more hardware description language (HDL) files. According to the method, in the HDL files, a configuration latch is specified within a design entity forming at least a portion of the digital design. In addition, a Dial is specified that defines a relationship between each of a plurality of input values and a respective one of a plurality of different output values. The HDL files also include a statement that instantiates an instance of the Dial in association with the configuration latch such that a one-to-one correspondence exists between a value contained within the configuration latch and an input value of the instance of the Dial. The HDL files further include a statement associating the Dial with a mapping function that applies a selected transformation to values read from or written to the instance of the Dial.

Abstract: A computer system reads data corresponding to an IC layout target layer and performs an etch simulation on the target layer. Etch biases are calculated and the inverse of the etch biases are used to produce a new target layer. The new target layer is provided as an input to an optical process correction (OPC) loop that corrects the data for image/resist distortions until a simulation indicates that a pattern of objects created on a wafer matches the new target layer. In another embodiment of the invention, original IC layout data is provided to both the OPC loop and an etch simulation. Etch biases calculated by the etch simulation are used in the OPC loop in order to produce mask/reticle data that will be compensated for both optical and resist distortions as well as for etch distortions.

Abstract: A system for dynamically compressing circuit components during simulating of a circuit having a hierarchical data structure includes a simulator module having one or more computer programs for 1) selecting a group of leaf circuits from the first and second branches for simulation, 2) if two or more leaf circuits of the circuit having a substantially same isomorphic behavior, representing the two or more leaf circuits as a merged leaf circuit, 3) creating a first port connectivity interface dynamically for the group of leaf circuits in response to the merged leaf circuit, where the first port connectivity interface communicates changes in signal conditions among the group of leaf circuits, and 4) simulating the group of leaf circuits in accordance with the first port connectivity interface.

Abstract: Translation of high-level design blocks into a design specification in a hardware description language (HDL). Each block in the high-level design is assigned to a group. A set of attributes is identical between the blocks in a group. For each group of blocks, a respective set of parameters having different values on subblocks of at least two blocks in the group is determined. An HDL specification is generated for each group. The HDL specification for a group has for each parameter in the set of parameters, a parameter input.

Abstract: A method of checking correctness of scheduling of a circuit where a schedule for the circuit is obtained from a behavioral description. The method comprising extracting loop invariants to determine a sufficient set of acyclic threads when loops are present, performing symbolic simulation to extract the above loop invariants, and proving equivalence of the acyclic threads. Systems, computer systems and computer program products that incorporate the techniques of verification and correctness checking according to the present invention have also been disclosed.

Abstract: A method and system for combining address anonymous hash arrays with clock, datapack and bit anonymous arrays to gather data of registers is disclosed. The method includes receiving a set of process inputs and a set of user inputs associated with a target system and processing a set of user-requested system-interface connections associated with the target system. An anonymous hash array for direct and special register addresses associated with the target system is created, as are a clock group, a datapack anonymous array and a bits anonymous array for a specified receiving bus. Whether a selected register is a special register is then determined. In response to determining that the selected register is a special register, reference to the anonymous hash array is performed to obtain an address for the selected register. Attribute data for the selected register is obtained and attribute data for the selected register is monitored.

Abstract: Method, system, and program product for expanding the effective capacity of embedded memory by storing data in a compressed form and reading the data out with subsequent data decompression, including adaptive decompression and data conversion. The system and method for compression and decompression of HDL code between HDL code storage and HDL code processing for simulation of a device or system.

Abstract: A test solution for one or more circuits implementing a communication standard is based on a design specification received from a development organization and a communication standard. The test solution is evaluated with one or more prototype circuits and is selectively modified based on the evaluation with the prototype circuits. The test solution is then evaluated with one or more manufactured circuits and is selectively modified based on the evaluation with the manufactured circuits.

Abstract: A electronic design automation tool, apparatus, method, and program product by which design requirements for an intended semiconductor product and the resource definitions of a semiconductor platform are input. From the design requirements and the resource definitions, parameters specific to clocking are derived, e.g., clock property information, clock domain crossing information, and clock relationship specification. The tool and method embodied therein validates the clocking parameters of the design requirements with the resource definitions and invokes errors if the parameters are not realizable. Once the desired clocking parameters are consistent with the actual clocking parameters, correct physical optimization constraints and timing constraints are generated for the clocks. An iterative process can achieve correct and minimal clocking constraints.

Abstract: A system and method for locating circuit deviations or circuit faults in a circuit in respect of a reference circuit. The circuit and the reference circuit are respectively describable by signal-flow graphs, the signal-flow graphs being composed of a multiplicity of interconnected function blocks. The function blocks of the circuit are first assigned to corresponding function blocks of the reference circuit. There are then ascertained those function blocks of the circuit and of the reference circuit for which assignment has not been possible, and which have disposed upstream in the signal flow at least one function block for which assignment has been possible. The result is a boundary between an assigned and a non-assigned region of the circuit and the reference circuit, respectively. A representation of the circuit and reference circuit is preferably produced in which the regions corresponding to the non-assigned function blocks are highlighted.

Abstract: A method of designing a wiring structure of an LSI is capable of reducing a capacitance variation ratio ?C/C or a resistance-by-capacitance variation ratio ?(RC)/(RC) of the wiring structure.

Abstract: Disclosed herein is a method of managing data results of simulation processing of a hardware description language (HDL) model based upon keywords. In accordance with the method, a restriction list associated with the HDL model is received. The HDL model has a maximum number of possible keyword/value pairs sets for which result data can be obtained, and the restriction list specifies a fewer number of keyword/value pair sets for which the result data can be queried based upon at least one keyword. In response to receipt of result data obtained by simulation of the HDL model, the result data are stored within a data storage subsystem by reference to the restriction list, such that particular result data attributable to each of the plurality of keyword/value sets is separately accessible.

Abstract: Methods and apparatus are provided for implementing a programmable device including a processor core and a hardware accelerator. A portion of a program written in a high-level language is automatically selected for hardware acceleration. Dedicated ports are generated to allow the hardware accelerator to handle pointer referencing and dereferencing. Profiling information is used to optimize selection of code for hardware acceleration.

Abstract: A system and method models regional timeout functionality in a discrete event execution environment. A timeout function is initiated associated with an entity upon occurrence of a start condition and terminated or reset upon reaching an end condition. The timeout function is configured to expire after a selected amount of time. Upon expiration of the timeout function, the entity is redirected to a predetermined location for timeout processing.

Abstract: Systems and methods for simulating signal coupling in electronic devices are disclosed. In an exemplary implementation a computer program product executes a computer process to simulate a victim signal having a toggling bit pattern relative to a quiet culprit signal. The process also simulates a culprit signal having a toggling bit pattern relative to a quiet victim signal. The computer process generates test results for each simulation and combines the test results to determine effects of signal coupling in an electronic device.

Abstract: A simultaneous satisfiability algorithm, or SSAT, allows simultaneous checks to be made efficiently for a number of literals, x1, . . . ,xn whether x1 is true under any satisfying assignments of a formula (written in conjunctive normal form) built from the variables of those literals and other variables (or, equivalently whether xl is a logical consequence of the formula). Thus, several related satisfiability checks are performed simultaneously in SSAT. Temporal induction algorithms allow the verification of the sequential behavior of finite state machines, e.g., hardware. Temporal induction algorithms may employ a SSAT solver to perform simultaneous model checking of several invariant (or safety) properties efficiently. These SSAT-based temporal induction algorithms are double-incremental, such that all learned clauses in the SSAT solver are re-used both across verified properties as well as across time frames.

Abstract: Movement of a soft body is simulated by defining its surface as an arbitrary mesh of points connected by edges. Each point is represented as a point mass, subject to conventional laws of motion. The simulator represents forces acting on the point masses, namely skin forces connecting pairs of point masses and volumetric forces for maintaining relative positions with no net linear or rotational forces on the soft body.

Abstract: A method and system for providing centralized access to count event information from testing of a hardware simulation model within a batch simulation farm which includes simulation clients and an instrumentation server. Count event data for said hardware simulation model is received by the instrumentation server from one or more simulation clients. A first and a second counter report are generated for the hardware simulation model, in which the first and second counter reports are derived from the count event data received by the instrumentation server. The first counter report is compared to the second counter report, and responsive to this comparison, a counter difference report is generated within the instrumentation server that conveys count event trends associated with the simulation model under different simulation testcases.

Abstract: In one embodiment, a method for invariant checking includes executing one or more first steps of a finite state machine (FSM) corresponding to one or more binary decision diagrams (BDDs) to traverse a state space of the FSM in a first direction with respect to an initial state and an erroneous state.

Abstract: A hardware model conversion system includes a logic synthesis tool and a hardware model conversion program. The logic synthesis tool logically synthesizes an HDL-described circuit and then outputs intermediate data. One assign statement described in the intermediate data is associated with one assign cell. The hardware model conversion program creates a logical structure table that shows a circuit connection relationship between the plural assign cells. The hardware model conversion program refers to the logical structure table and executes model conversion of the HDL-described circuit to a pipeline structure so that assign cells having the same logic depth will belong to the same pipeline stage.

Abstract: A method for emulating a logic circuit having at least one set of identical logic modules is disclosed. Each logic module in a set has logic elements and memory elements that store a module state of that logic module. The logic circuit is emulated by extracting a logic module from a set of identical logic modules, translating the extracted logic module for iterative representation of the module state of each of the logic modules with a single instance of the logic elements, and configuring a logic device with the translated logic module to emulate the logic circuit.

Abstract: Genie is a described computer chip design tool which can analyze the data contained within an entire endpoint report, compute relationships between paths based on shared segments, and display this information graphically to the designer. Specifically, Genie groups failing paths into Timing Islands. A timing island is a group of paths which contain at least one shared segment. The most frequently shared segment is sifted to the top of the priority list for each island, and is labeled as the Hub. Thinking of timing islands as a tree, the hub of the island would be the trunk. If you chop the tree down by the trunk, all of the branches, limbs and twigs will fall down too. This is analogous to fixing the timing failures in the hub, and the fix trickling out to each of the segments that dangle off the hub.

Abstract: Access to a signals of a user design in a programmable logic device (PLD) is provided without a compilation delay following selection of the signals. The system may include a generator, a compiler, a selector, the PLD, and a monitor. The generator selects sets of signals of the user design, and for each set of signals, generates a respective supplement of a subset of the user design supplementing the subset with a logic analyzer coupled to the set of signals. The compiler generates a respective configuration for each supplement. The selector selects a configuration or multiple configurations responsive to the specified set of signals and the sets of signals. The PLD implements the user design after the PLD is programmed with the selected configuration or configurations. The monitor accesses the specified set of signals in the PLD via the logic analyzer corresponding to each of the selected configuration or configurations.

Abstract: Statistical timing analysis methods for circuits are described which compensate for circuit elements having correlated timing delays with a high degree of computational efficiency. An extended canonical timing model is used to represent each delay element along a circuit path, wherein the model bears information regarding any correlations that each element has to any other elements in the circuit (and/or to any external global factors, e.g., global temperature variations over the circuit, etc.). The model can be represented in a vectorized format which allows enhancement of computational efficiency, wherein the coefficients of the vectors allow an objective measure of element correlation (and wherein the vectors can be “pruned” by dropping insignificant coefficients to further enhance computational efficiency). A decomposition procedure can be used to decompose correlated elements into uncorrelated elements to allow delays to me more easily propagated through the timing diagram representing the circuit.

Abstract: A method for extracting capacitance from a layout record includes solving a matrix equation to obtain a set of capacitors that account for metal fill while eliminating floaters. A method for extracting capacitance from a layout record includes partitioning floaters into disjoint sets, and converting a capacitance matrix into block-diagonal form by ordering conductors according to the disjoint sets.

Abstract: A method, data processing system, and computer program product are provided for performing time-based symbolic simulation. A delay-aware representation of a circuit is created that includes a plurality of circuit nodes. The data-aware representation is simulated. In particular, the simulator simulates transitions from a first set of circuit nodes to a second set of circuit nodes selected from the plurality of circuit nodes, the simulating based on executing a first set of simulation events. A second set of simulation events is then generated in response to executing the first set of simulation events. During the simulation, a time is computed for each of the transitions. An an event scheduling diagram is constructed during simulation. The event scheduling diagram depicts the transitions and the times of the transitions.

Abstract: The monitor manager manages the execution of monitors during the simulation of a digital design. The monitor manager (20) includes an instance generator (32) that creates executable instances (38) of monitors that may be time-dependent monitors, an activation manager (34) that assigns instances to be active or inactive, and an execution unit (36) that executes active instances and receives returned status values passed, failed, active, or error. Executable instances of time-dependent monitors are software state machines having a state variable, one or more time-dependent variables, and at least two state-driven code blocks, at least one of which might be either a cycle-dependent code block that tests for a specific cycle-dependent condition, or an event-dependent code block that tests for a specific event-dependent condition. In either case, the state-driven code block increments the time-dependent variable, and, when the condition has been satisfied, increments the state variable.

Abstract: A method for selecting and/or producing automation hardware which is appropriate or necessary for controlling and/or monitoring a technical process to be automated (10) according to an automation solution is provided. The method includes developing the description of the automation solution, analyzing this description with an analysis tool (20) and selecting and, where applicable, producing respective automation hardware on the basis of the analysis of the description.

Abstract: A method and computer program for static timing analysis includes receiving as input minimum and maximum stage delays for two corners of an integrated circuit design. A path slack for a setup timing check is calculated from the minimum and maximum stage delays as a function of net clock cycle interval T_clk, launch path delay T_LP, capture path delay T_CP, data path delay T_DP, and a first delay de-rating factor Y1. A path slack for a hold timing check is calculated from the minimum and maximum stage delays as a function of the launch path delay T_LP, the capture path delay T_CP, the data path delay T_DP, and a second delay de-rating factor Y2. The path slack calculated for the setup timing check and for the hold timing check is generated as output.

Abstract: Techniques for performing static and dynamic race logic analysis on an integrated circuit (IC) are described herein. According to one aspect of the invention, HDL (hardware description language) design source files of an IC design are compiled into a common design database, including recording full timing information of the IC design. A static race logic analysis is performed on the common design database to reveal all possible race logic in the IC design. A dynamic race logic analysis could also be performed on the common design database to reveal times and circuit locations where the race logic would occur when a physical IC chip for the IC design is implemented. A race logic analysis report is generated for the static and/or dynamic race logic analysis, where the race logic analysis report is used to eliminate race logic errors in IC designs, so as to render highest quality IC products that will not exhibit intermittent random failures in field operations.

Abstract: A method and system to automate scan synthesis at register-transfer level (RTL). The method and system will produce scan HDL code modeled at RTL for an integrated circuit modeled at RTL. The method and system comprise computer-implemented steps of performing RTL testability analysis, clock-domain minimization, scan selection, test point selection, scan repair and test point insertion, scan replacement and scan stitching, scan extraction, interactive scan debug, interactive scan repair, and flush/random test bench generation. In addition, the present invention further comprises a method and system for hierarchical scan synthesis by performing scan synthesis module-by-module and then stitching these scanned modules together at top-level. The present invention further comprises integrating and verifying the scan HDL code with other design-for-test (DFT) HDL code, including boundary-scan and logic BIST (built-in self-test).

Abstract: A method is provided for modeling timing characteristics of a circuit block of an integrated circuit, which includes a main circuit and a timing circuit. The method comprises determining an output pin output delay and determining a timing circuit delay. The output pin output delay is an interval of time from a clock signal reaching a clock reference point (CRP) to an output signal arriving at the output pin. The clock reference point is positioned between the timing circuit and the main circuit. The timing circuit delay is an interval of time from a clock signal arriving at a clock input pin to a clock signal arriving at the CRP. The determination of the timing circuit delay is based on a computer simulation of a netlist of circuit elements in the timing circuit.

Abstract: A hybrid linear wire model for tuning the transistor widths of circuits linked by RC interconnects is described. The method uses two embedded simulators during the tuning process on netlists that contain resistors (Rs). A Timing oriented simulator is used only for timing purposes on the original netlist that includes all the Rs. A Gradient oriented simulator is then run only on the modified netlist with all Rs shorted and within the iterative loop of the tuner to compute gradients. The present hybrid method achieves a significant improvement in computational speed. The Timing oriented simulator is fast and accurate for only timing netlists with Rs, but cannot compute gradients efficiently. The Gradient oriented simulator computes gradients efficiently but cannot do so in the presence of Rs.

Abstract: A delay analysis device includes a receiving unit that receives a result of a timing analysis of a target circuit to be analyzed, a detecting unit that detects critical paths having delays within a predetermined range, a statistical-delay computing unit that computes a statistical delay of the target circuit based on a cumulative probability distribution of the delays of the critical paths, and a probability-density-distribution computing unit that computes a probability density distribution of delay of a critical path that has the greatest delay in the result. The detecting unit detects x number of critical paths having cumulative delays within computed probability density distribution.