Method and apparatus for random stimulus generation
US6499127B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1999 |
| Grant date | Dec 24, 2002 |
| Priority date | — |
| Expiry date | Apr 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/318342
- 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. A constraint_expression can constrain any random variable which has been declared at its level in the class hierarchy, or at any higher level. A constraint_expression cannot constrain a random variable declared at a lower level in the hierarchy. 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…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.