Axis Systems, Inc

Cadence Design Systems, Inc.

Synopsys, Inc.

Versity Design, Inc.

Ping-Sheng Tseng

Sharon Sheau-Pyng Lin

Quincy Kun-Hsu Shen

Steven Wang

Radha Vaidyanathan

Ren-Song Tsay

Yogesh Goel

Richard Yachyang Sun

Mike Mon Tsai

Mike Mon Yen Tsai

Song Peng

Mitchell Grant Poplack

Christian Wiencke

Sivaram Krishna Nayudu

Su-Jen Hwang

Mahadevan Ganapathi

Kun-Hsu K Shen

Chwen-Cher Chang

Bhoumik Shah

Naresh Ramachandran

Sharon Sheau-Ping Lin

G B Ashok

Amy Lim

Embodiments described herein provide for an emulation system that supports efficiently generating outgoing messages to a test bench. The emulation system transmits the outgoing messages to the test bench various busses and interfaces. The compiled virtual logic writes the outgoing messages into memories of the emulation chips for queuing, and notification messages associated with the queued outgoing messages. A traffic processor transfers from memories to the test bench using buses and interfaces. The traffic processor reads a notification message from memory to identify the storage location with a corresponding queued outgoing message. The traffic processor then transmits DMA requests to I/O components (e.g., DMA engines) to instruct the I/O components to transfer the queued outgoing message to the host device.

Systems and methods for handling DPI messages outgoing from an emulator system

The debug system described in this patent specification provides a system that generates hardware elements from normally non-synthesizable code elements for placement on an FPGA device. This particular FPGA device is called a Behavior Processor. This Behavior Processor executes in hardware those code constructs that were previously executed in software. When some condition is satisfied (e.g., If . . . then . . . else loop) which requires some intervention by the workstation or the software model, the Behavior Processor works with an Xtrigger device to send a callback signal to the workstation for immediate response.

Common shared memory in a verification system

The present patent document relates to a method and apparatus for more efficiently simulating a circuit design (DUT), making use of a hardware functional verification device such as a processor-based emulator. A set of linked databases are compiled for the DUT, one for hardware emulation (without timing information for the DUT) and one for software simulation (including timing information) that remain synchronized during runtime. The compiled design is run in a hardware emulator during an initialization/configuration phase and the state saved. The state is then swapped to a software simulator where timing information, such as SDF timing, may be honored during the second part of the run and the user's test bench stimuli applied to the design.

Co-simulation methodology to address performance and runtime challenges of gate level simulations with, SDF timing using emulators

Method and apparatus for simulating a circuit using timing insensitive glitch-free (TIGF) logic

Method and apparatus for implementing a task-based interface in a logic verification system is described. In some examples, a task server and a context memory are implemented in a hardware accelerator for a task. The task server is configured for communication with the logic design. A task stub configured for execution by a computer for the task is generated. Calls to the task are received from a test bench in the computer at the task stub. Remote procedure call (RPC) channels are established in response to the calls. Values of input arguments for the calls are transferred to the context memory through the RPC channels. Execution of threads of the task in the task server is triggered using the values of the input arguments in the context memory as parametric input.

Method and apparatus for implementing a task-based interface in a logic verification system

Method and apparatus for processing assertions in assertion-based verification of a logic design are described. One example relates to processing an assertion during verification of a logic design. An evaluation engine is generated that encodes, using a non-deterministic finite automata (NFA) model, temporal behavior of the logic design required by the assertion for a single attempt to evaluate the assertion. The evaluation engine is implemented in first reconfigurable hardware. The logic design is simulated over a plurality of clock events. Attempts to evaluate the assertion by the evaluation engine are preformed sequentially based on input stimuli obtained from the logic design during simulation thereof. Each of the attempts results in one of the assertion passing, the assertion failing, or the assertion requiring further evaluation.

Method and apparatus for processing assertions in assertion-based verification of a logic design

Method and apparatus for translating a verification process having recursion for implementation in a logic emulator are described. Examples of the invention relate to a method, apparatus, and computer readable medium for translating a verification process for implementation in a hardware emulator of a logic verification system. A recursive task called by the verification process is identified. A copy of the recursive task is incorporated into the verification process. Interface registers are instantiated for the recursive task. Control flow transfer points are defined in the verification process. Calls of the recursive task are converted in the verification process to constructs for accessing the interface registers and transferring control flow among the control flow transfer points. The verification process is reorganized to describe a finite state machine (FSM) configured for implementation in the hardware emulator.

Method and apparatus for translating a verification process having recursion for implementation in a logic emulator

The complexity of user designs, the limited capacity of FPGA chips, and the limited number of chip pinouts have resulted in the development of inter-chip communication technology that necessitates the transfer of a large amount of data across a limited number of pins in the shortest amount of time. The inter-chip communication system transfers signals across FPGA chip boundaries only when these signals change values. Thus, no cycles are wasted and every event signal has a fair chance of achieving communication across chip boundaries. The inter-chip communication system includes a series of event detectors that detect changes in signal values and packet schedulers which can then schedule the transfer of these changed signal values to another designated chip. Working with a plurality of signal groups that represents signals at the separated connections, the event detector detects events (or changes in signal values). When an event has been detected, the event detector alerts the packet scheduler. The packet scheduler employs a token ring scheme as follows. When the packet scheduler receives a token and detects an event, the packet scheduler 'grabs' the token and schedules the transmission of this packet in the next packet cycle. If, however, the packet scheduler receives the token but does not detect an event, it will pass the token to the next packet scheduler. At the end of each packet cycle, the packet scheduler that grabbed the token will pass the token to the next logic associated with another packet.

Inter-chip communication system

In the VCD-On-Demand system, the EDA tool has the following attributes: (1) RCC-based parallel simulation history compression and recording, (2) RCC-based parallel simulation history decompression and VCD file generation, and (3) On-demand software regeneration for a selected simulation target range without simulation rerun. When the user selects a simulation session range, the RCC System records a highly compressed version of the primary inputs from the test bench process. The user then selects a narrower region, the simulation target range, within the simulation session range for a more focused analysis. The RCC System dumps the hardware state information of the hardware model into a VCD file. The RCC System then allows the user to proceed directly to view the VCD file from the beginning of the simulation target range without having to rerun the entire simulation from the beginning of the simulation session range.

VCD-on-demand system and method

A debug system generates hardware elements from normally non-synthesizable code elements for placement on an FPGA device for used in electronic design automation (EDA). The FPGA device (Behavior Processor) operates to execute in hardware code constructs previously executed in software. When some condition is satisfied (e.g. If . . . then . . . else loop) requiring intervention, the Behavior Processor works with an Xtrigger device to send a callback signal to the workstation for immediate response. A memory block from a logic device is mapped to a memory device in a re-configurable hardware unit using a memory mapping system including a conductive connector driver, a memory block interface, and evaluation logic in each logic device, the connector driver, the interface, and the connector controller, the evaluation logic providing control signals used to evaluate data in the hardware model and to control write/read memory access between the logic device and the memory device via the driver and interface.

Memory mapping system and method

An emulation system includes a clock generation logic for generating multiple asynchronous clocks, where each generated clock's relative phase relationship with respect to all other generated clocks is strictly controlled to speed up the emulation logic evaluation. Unlike statically designed emulator systems known in the prior art, the speed of the logic evaluation in the emulator need not be slowed down to the worst possible evaluation time since the clocking is generated internally in the emulator and carefully controlled. The emulation system does not concern itself with the absolute time duration of each clock, because only the phase relationship among the multiple asynchronous clocks is important. By retaining the phase relationship (and the initial values) among the multiple asynchronous clocks, the speed of the logic evaluation in the emulator can be increased. The RCC clock generation logic comprises a clock generation scheduler and a set of clock generation slices, where each clock generation slice generates a clock. The clock generation scheduler compares each clock's next toggle point from the current time, toggles the clock associated with the winning next toggle point, determines the new current time, updates the next toggle point information for all of the clock generation slices, and performs the comparison again in the next evaluation cycle. In the update phase, the winning slice updates its register with a new next toggle point, while the losing slices merely updates their respective registers by adjusting for the new current time.

Emulation system with multiple asynchronous clocks

In a verification system, a dynamic logic evaluation system and method dynamically calculates the minimum evaluation time for each input. Thus, this system and method will remove the performance burden that a fixed and statically calculated evaluation time would introduce. By dynamically calculating different evaluation times based on the input, 99% of the inputs will not be delayed for the sake of 1% of the inputs that actually need the worst possible evaluation time. The dynamic logic evaluation system and method comprises a global control unit coupled to a propagation detector, where the propagation detector is placed in each FPGA chip. The propagation detector in the FPGA chip alerts the global control unit of any input data that is currently propagating within the FPGA chips. A master clock controls the operation of this dynamic evaluation system and method. As long as any input data is propagating, the global control unit will prevent the next input from being provided to the FPGA chips for evaluation. Once the output has stabilized, the global control unit will then instruct the system to accept and process the next set of input data. Thus, the global control unit in conjunction with the propagation detectors can dynamically provide varying evaluation time periods based on the needs of the input data. Whether the system needs longer or shorter evaluation times, the system will dynamically adjust the amount of time necessary to properly process that input and then move on to the next evaluation time for the next set of inputs.

Dynamic evaluation logic system and method

The coverification system includes a reconfigurable computing system (hereinafter &ldquo;RCC computing system&rdquo;) and a reconfigurable computing hardware array (hereinafter &ldquo;RCC hardware array&rdquo;). In some embodiments, the target system and the external I/O devices are not necessary since they can be modeled in software. In other embodiments, the target system and the external I/O devices are actually coupled to the coverification system to obtain speed and use actual data, rather than simulated test bench data. The RCC computing system contains a CPU and memory for processing data for modeling the entire user design in software. The RCC computing system also contains clock logic (for clock edge detection and software clock generation), test bench processes for testing the user design, and device models for any I/O device that the user decides to model in software instead of using an actual physical I/O device. The user may decide to use actual I/O devices as well as modeled I/O devices in one debug session. The software clock is used as the external clock source for the target system and the external I/O devices to synchronize all data that is delivered between the coverification system and the external interface. The coverification system contains a control logic that provides traffic control between: (1) the RCC computing system and the RCC hardware array, and (2) the external interface (which are coupled to the target system and the external I/O devices) and the RCC hardware array. Because the RCC computing system has the model of the entire design in software, including that portion of the user design modeled in the RCC hardware array, the RCC computing system must also have access to all data that passes between the external interface and the RCC hardware array. The control logic ensures that the RCC computing system has access to these data. Pointers are used to latch data from the RCC computing system and the external interface to the internal nodes of the hardware model in the RCC hardware array. Pointers are also used to deliver data from the internal nodes of the hardware model to the RCC computing system and the external interface. Even if the data from the internal nodes of the hardware model is intended for the external interface, the RCC computing system must also be able to access this data as well.

Converification system and method

The disclosed devices are several forms of a timing insensitive glitch-free (TIGF) logic device. The TIGF logic device can take the form of any latch or edge-triggered flip-flop. In one embodiment, a trigger signal is provided to update the TIGF logic device. The trigger signal is provided during a short trigger period that occurs at adjacent times from the evaluation period. In latch form, the TIGF latch includes a flip-flop that holds the current state of the TIGF latch until a trigger signal is received. A multiplexer is also provided to receive the new input value and the old stored value. The enable signal functions as the selector signal for the multiplexer. Because the trigger signal controls the updating of the TIGF latch, the data at D input to the TIGF latch and the control data at the enable input can arrive in any order without suffering from hold time violations. Also, because the trigger signal controls the TIGF updates, the enable signal can glitch often without negatively affecting the proper operation of the TIGF latch. In flip-flop form the TIGF flip-flop includes a first flip-flop that holds the new input value, a second flip-flop that holds the current stored value, and a clock edge detector. All three of these components are controlled by the trigger signal for updating the TIGF flip-flop. A multiplexer is also provided with the edge detector signal functioning as the selector signal. Because one dedicated first flip-flop stores the new input value which effectively blocks input changes during evaluation, hold time violations are avoided. With the trigger signal controlling the TIGF flip-flop updates, clock glitches do not affect the hardware model of the user design circuit that uses the TIGF flip-flop as the emulated flip-flop.

Timing-insensitive glitch-free logic system and method

The SEmulation system provides four modes of operation: (1) Software Simulation, (2) Simulation via Hardware Acceleration, (3) In-Circuit Emulation (ICE), and (4) Post-Simulation Analysis. At a high level, the present invention may be embodied in each of the above four modes or various combinations of these modes. At the core of these modes is a software kernel which controls the overall operation of this system. The main control loop of the kernel executes the following steps: initialize system, evaluate active test-bench processes/components, evaluate clock components, detect clock edge, update registers and memories, propagate combinational components, advance simulation time, and continue the loop as long as active test-bench processes are present. A Simulation server in accordance with an embodiment of the present invention allows multiple users to access the same reconfigurable hardware unit to effectively simulate and accelerate the same or different user designs in a time-shared manner in both a network and a non-network environment. The server provides the multiple users or processes to access the reconfigurable hardware unit for acceleration and hardware state swapping purposes. The Simulation server includes the scheduler, one or more device drivers, and the reconfigurable hardware unit. The scheduler in the Simulation server is based on a preemptive round robin algorithm. The server scheduler includes a simulation job queue table, a priority sorter, and a job swapper.

Growing community of inventors

Saratoga, CA, United States of America

Ping-Sheng Tseng