Synopsys, Inc.

Alexander Rabinovitch

Ludovic Marc Larzul

Cedric Jean Alquier

Baijayanta Ray

Manish Shroff

Xavier Guerin

Ramesh Narayanaswamy

Daniel Geist

Boris Gommershtadt

Dmitry Korchemny

Sebastien Delerse

Etienne Lepercq

Sébastien Roger Delerse

Bojan Mihajlovic

Srivatsan Raghavan

Fei Chen

A method includes determining a plurality of signals that have been selected for waveform capture, forming, based on a respective numbers of clock cycles for the plurality of signals to update, a first group of signals and a second group of signals, sampling the first group of signals according to a first sampling clock signal to produce a first set of sampled signals, and sampling the second group of signals according to a second sampling clock signal to produce a second set of sampled signals. The method also includes generating a waveform capture frame based on the first set of sampled signals and the second set of sampled signals.

Waveform capture using multicycle path properties

Circuit designs are emulated to verify the functionality of the circuit design. Emulating the circuit design includes obtaining a circuit design. The circuit design includes clock signals. Each of the clock signals is a data path clock signal. Further, a first clock signal of the clock signals is determined to be faster than a second clock signal of the clock signals. Rising edges and falling edges of the second clock signal are aligned with rising edges of the first clock signal to generate a realigned clock signal based on determining that the first clock signal is faster than the second clock signal. The circuit design is emulated using the realigned clock signal.

Clock signal realignment for emulation of a circuit design

A system and method for emulation receives a circuit design driven by a primary clock signal. The circuit design includes reset circuitry and sequential circuitry connected to the reset circuitry. The circuit design includes a secondary clock signal that is slower than the primary clock signal. The reset circuitry generates a reset signal that is a function of the secondary clock signal. The secondary clock signal is remodeled at a transition edge of the primary clock signal, and a predicted reset signal is generated subsequent to the reset signal at the transition edge of the primary clock signal. An operation of the circuit design is emulated based on the predicted reset signal such that the predicted reset signal from the reset circuitry propagates through multiple cycles of the primary clock signal.

Multicycle path prediction of reset signals

Emulating a circuit design includes remodeling the clock signals of the circuit design. A circuit design includes clock signals that are based on a root clock signal. The clock signals are analyzed to identify a first clock signal of the clock signals that is faster than a second clock signal of the clock signals. The second clock signal is remodeled based on the first clock signal. An updated circuit design is generated based on remodeled second clock signal, and operation of the updated circuit design is emulated.

Transformations for multicycle path prediction of clock signals

A system is disclosed that includes a memory, and a processor configured to perform operations stored in the memory. The processor performs the operations to analyze each of a first set of sequential elements of a plurality of sequential elements to determine an edge of a clock signal pattern of a clock associated with each of the first set of sequential elements causing an output change at corresponding one or more sequential elements of the first set of sequential elements. The processor further performs the operations to discard one or more cycles of the clock signal pattern of the clock from emulation that do not include the edge of the clock signal pattern that causes at least one sequential element of the first set of sequential elements to change the output and emulate remaining cycles of the clock signal pattern of the clock.

System and method for optimizing emulation throughput by selective application of a clock pattern

The independent claims of this patent signify a concise description of embodiments. A method is provided for reducing a size of an emulation clock tree for a circuit design. The method comprises identifying a fan-in cone of an input of a sequential element of the circuit design; identifying one or more fan-in cone sequential elements which do not directly affect the input of the sequential element; and removing the one or more identified fan-in cone sequential elements of the fan-in cone from the emulation clock tree. This Abstract is not intended to limit the scope of the claims.

Method and system for emulation clock tree reduction

The independent claims of this patent signify a concise description of embodiments. A hardware emulation system is configured to define a variable delay associated with each of a multitude of design clocks used in the circuit design, compute a compression value in accordance with the multitude of variable delays, detect a change in one or more of the variable delays, and recompute the time compression value in response to the detected change. The hardware emulation system is further configured to recompute the time compression using programmable circuitry disposed in the hardware emulation system and without stopping the hardware emulation system. Such circuitry may be disposed in a single programmable device disposed in the hardware emulation system or a multitude of programmable devices disposed in the hardware emulation system. This Abstract is not intended to limit the scope of the claims.

Method for compression of emulation time line in presence of dynamic re-programming of clocks

A hardware verification system according to one embodiment includes, in part, a plurality of programmable devices. The plurality of programmable devices include a master scheduler, a plurality of schedulers and a plurality of programmable delay elements. A first one of the plurality of schedulers is configured to receive one or more delay values associated with one or more of the plurality of delay elements. Each of the plurality of programmable delay elements corresponds to a delay. The first scheduler is further configured to send a parameter corresponding to the one or more delay values to the master scheduler, and generate one or more signals corresponding to the one or more delay elements in response to a control signal the first scheduler receives from the master scheduler.

Method and apparatus for modeling delays in emulation

Some embodiments of the present invention provide techniques and systems for simulating a circuit design so that the simulation follows hardware semantics. Specifically, some embodiments ensure that the simulation follows hardware semantics by properly handling race conditions in state elements and/or glitches in clock trees that can occur during logic simulation. Each logic simulation cycle can include two stages: a stimuli application stage in which the system evaluates signal values of the circuit design which do not depend on a clock signal, and a clock propagation stage in which the system evaluates signal values that depend on a clock signal. Some embodiments of the present invention sample signal values during the stimuli application stage, and use the sampled signal values during the clock propagation stage to handle race conditions in state elements and/or glitches in clock trees that may occur during logic simulation.

Logic simulation and/or emulation which follows hardware semantics

A hardware verification system includes, in part, a multitude of programmable devices and a system clock. The hardware verification system receives a circuit design and generates a variable period clock from the system clock by analyzing propagation delays in different signal paths of the circuit design. The variable period clock has a first period that occurs in each N cycles of the system clock and a second period that occurs in each M cycles of the system clock, in which M&#x3e;N. The variable period clock is applied to at least one of the programmable devices to verify the circuit design.

Method and apparatus for emulation and prototyping with variable cycle speed

A computer-implemented method for configuring a hardware verification system is presented. The method includes receiving a first data representative of a first design including a first sequential element configured to be evaluated in accordance with a first signal. The method further includes transforming the first data into a second data representative of a second design. The second data includes a third data associated with a second sequential element including functionality of the first sequential element and a fourth data associated with a first logic circuit. The evaluation of the second sequential element at cycle i of the hardware verification system is performed in accordance with the first logic circuit and a value of the first signal as computed during cycle i&#x2212;1 of the hardware verification system when the second data is compiled for programming into the hardware verification system, where i is an integer number.

Overlaying of clock and data propagation in emulation

A computer-implemented method for configuring a hardware verification system includes receiving, in the computer, a first data representative of a first design. The method further includes performing a first mapping of the first data to generate a second data in accordance with a first cost function and one or more first delays each associated with a different one of a first multitude of paths. One of the first multitude of paths includes a critical path characterized by a second delay. The method further includes performing a second mapping of the second data to generate a third data in accordance with a second cost function and a multitude of third delays each associated with a different one of a second multitude of paths and the second delay. The method further includes compiling the third data for configuring the hardware verification system.

Partitioning and routing multi-SLR FPGA for emulation and prototyping

A computer-implemented method for configuring a hardware verification system is presented. The method includes receiving, in the computer, a first code representing a first design including a first latch configured to be evaluated in accordance with a first signal, when the computer is invoked to configure the verification system. The method further includes changing, using the computer, the first code into a second code representing a second design, the changing further including transforming, using the computer, the first latch into a second latch configured to be evaluated in accordance with a second signal different from the first signal after the first signal is received at the second latch, when the second code for the second design is compiled for programming into the hardware verification system.

Efficient resolution of latch race conditions in emulation

Embodiments relate to the emulation of circuits, and representation of unknown states of signals. A disclosed system (and method and computer program product) includes an emulation environment to convert a digital signal of a DUT in a form capable of representing an unknown state. In addition, the disclosed system converts digital logic circuits such as Boolean logic, flip flops, latches, and memory circuits to be operable with signals having unknown states. Thus, an unknown state of a signal is indicated and propagated through digital logic circuits represented in a disclosed semantic to enable prompt detection of improper operation of the DUT, for example, due to power shut down or inadequate initialization.

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Shrewsbury, MA, United States of America

Alexander Rabinovitch