Method and apparatus for random stimulus generation
US6513144B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1999 |
| Grant date | Jan 28, 2003 |
| Priority date | — |
| Expiry date | Apr 22, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99945
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention adds capabilities to a Hardware Verification Language (HVL) which facilitate the generation of random test data. Sources of random numbers are easily produced by simply adding a randomness attribute to a variable declaration of a class definition. Such variables are called random variables. A “randomize” method call may be made to an instance of the class definition to produce random values for each random variable. The values assigned to random variables are controlled using constraint blocks, which are part of the class definition. A constraint block is comprised of constraint expressions, where each constraint expression limits the values that can be assigned to a random variable on the left-hand-side (lhs) of the constraint expression. If a constraint block of an instance is active or ON, then all the constraint expressions in the block will act to constrain their lhs random variable. A constraint block which is OFF means that all of its constraint expressions will not act to constrain their random variables. The method “constraint_mode” can be used to turn ON or OFF any constraint blocks of an instance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.