Cycle Based Simulation

Mehrdad Abutalebi

Outline

Motivation

Cycle Simulation

Cycle Simulation Techniques

Cycle Simulation Specifications

Areas of Applicability

Motivation

Advanced today’s technologiesLarge circuit densitiesLarge verification time

Time to market

Need for faster simulators

New innovation and techniquesCycle based simulation

Cycle Simulation

Cycle simulation is a technique for simulating circuits that do not take into account the detailed circuit timing

Cycle simulation computes the steady state response of the circuit at each clock cycle boundary

Need for another tool for timing analysis

Cycle Simulation

Cycle Simulation TechniquesEvent ordering and delayed evaluationAll scheduled evaluations will take place at

active edge of clock All events are put in an event orderer

which eliminate unnecessary evaluations

Cycle Simulation TechniquesCycle based oblivious simulationLogic levelization is applied to the designClocked elements are clocked at active

edgeCombinational logic is evaluated during the

cycle

Cycle Simulation Specifications

Ignore timing and reducing the state set(2 value and sometime 4 value) Efficient evaluation and faster simulation

Circuit levelization at compile time Each element is evaluated once during clock cycle

Simple data structure for simulator

10 to 100 times performance over event driven simulation

Areas of Applicability

Large synthesizable or logic optimizable designs

Designs that are mostly synchronous

Designs meet the cycle simulation subsetRTL regressionGate-level verification