A method comprising using at least one hardware processor for: running a Monte Carlo simulation of possible integrated circuit (IC) process variations of each of a plurality of IC cell types, wherein each of the plurality of IC cell types is defined by multiple specific transistors and multiple specific interconnects; based on the results of the Monte Carlo simulation, creating a library of IC cell types and their corresponding behavioral values for each of the possible IC process variations, and storing the library in a non-transient memory; receiving an IC design embodied as a digital file; correlating the received IC design with the library; and predicting a frequency distribution and a power distribution of ICs manufactured according to the IC design.

Disclosed is a method and apparatus that takes timing information associated with a plurality of inputs to a cell, such as an AND-gate, within an integrated circuit (IC) design, store the timing information in a timing information register (TIR) associated with an index identifying the source of the timing information and track the source of the timing information for a predetermined number of cells through the index. The timing information in the TIRs is merged upon the index indicating that the timing information has been tracked through a predetermined number of cells.

Disclosed is a method and apparatus that takes timing information associated with a plurality of inputs to a cell, such as an AND-gate, within an integrated circuit (IC) design, store the timing information in a timing information register (TIR) associated with an index identifying the source of the timing information and track the source of the timing information for a predetermined number of cells through the index. The timing information in the TIRs is merged upon the index indicating that the timing information has been tracked through a predetermined number of cells.

The technology disclosed relates to verifying metastability for a clock domain crossing (CDC) in a circuit design. The technology disclosed may include, for a destination clock domain in the circuit design, creating a circuit graph based, at least in part, on the circuit design. The circuit graph includes start points and stop points. The start points may be data inputs, clocks, and enables of the destination clock domain. The stop points may be synchronizer outputs of the destination clock domain and a source clock domain in the circuit design. The technology disclosed may also include traversing the circuit graph to mark all graph nodes that reside in a source-destination path of the CDC. Based on the marked graph nodes, the start points, and the stop points, the technology disclosed may also include propagating destination domain qualifiers on the circuit graph within an allowed sequential depth.

Disclosed in the present invention is a flexible modeling method for a timing constraint of a register. Simulation ranges of input terminal transition time, clock terminal transition time, and output load capacitance of a register are determined first, simulation is performed under each combination of input terminal transition time, clock terminal transition time, and output load capacitance to obtain a timing constraint range, then setup slack and hold slack are extracted in this constraint range with a particular interval, and then simulation is performed to obtain a clock terminal-to-output terminal delay. Finally, a mutually independent timing model of the register is established by using an artificial neural network, where the clock terminal-to-output terminal delay is modeled as a function of the input terminal transition time, the clock terminal transition time, the output load capacitance, the setup slack, the hold slack, and an output terminal state. A flexible timing constraint model in the present invention has advantages of low simulation overheads and high prediction precision, and is of great significance for static timing analysis timing signoff of a digital integrated circuit.

Disclosed in the present invention is a flexible modeling method for a timing constraint of a register. Simulation ranges of input terminal transition time, clock terminal transition time, and output load capacitance of a register are determined first, simulation is performed under each combination of input terminal transition time, clock terminal transition time, and output load capacitance to obtain a timing constraint range, then setup slack and hold slack are extracted in this constraint range with a particular interval, and then simulation is performed to obtain a clock terminal-to-output terminal delay. Finally, a mutually independent timing model of the register is established by using an artificial neural network, where the clock terminal-to-output terminal delay is modeled as a function of the input terminal transition time, the clock terminal transition time, the output load capacitance, the setup slack, the hold slack, and an output terminal state. A flexible timing constraint model in the present invention has advantages of low simulation overheads and high prediction precision, and is of great significance for static timing analysis timing signoff of a digital integrated circuit.

A system and method for changing a circuit design are described. The method includes generating a propagation graph for the circuit design and estimating slack values for some of the paths in the propagation graph. The method also includes making a virtual change to the circuit design and determining whether to accept or reject the change based on how the change affects the estimated slack values.

A system and method for changing a circuit design are described. The method includes generating a propagation graph for the circuit design and estimating slack values for some of the paths in the propagation graph. The method also includes making a virtual change to the circuit design and determining whether to accept or reject the change based on how the change affects the estimated slack values.

A multi-bit flip-flop includes a first flip-flop, a second flip-flop and a first inverter. The first flip-flop has a first driving capability, and includes a first reset pin configured to receive a first reset signal. The second flip-flop has a second driving capability different from the first driving capability. The second flip-flop includes a second reset pin configured to receive the first reset signal, and the first reset pin and the second reset pin are coupled together. The first inverter is configured to receive a first clock signal on a first clock pin, and configured to generate a second clock signal inverted from the first clock signal. The first flip-flop and the second flip-flop are configured to share at least the first clock pin.

A multi-bit flip-flop includes a first flip-flop, a second flip-flop and a first inverter. The first flip-flop has a first driving capability, and includes a first reset pin configured to receive a first reset signal. The second flip-flop has a second driving capability different from the first driving capability. The second flip-flop includes a second reset pin configured to receive the first reset signal, and the first reset pin and the second reset pin are coupled together. The first inverter is configured to receive a first clock signal on a first clock pin, and configured to generate a second clock signal inverted from the first clock signal. The first flip-flop and the second flip-flop are configured to share at least the first clock pin.