8.2.2 - Property Checking
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Introduction to Property Checking
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Today we’re going to discuss property checking in RTL verification. Can anyone tell me what they think property checking might involve?
Maybe it has something to do with testing if the properties of a design are confirmed?
Exactly! Property checking is about verifying whether certain expected behaviors hold true for any possible input. We use formal methods to achieve this.
What kind of properties are we checking for?
Great question! We check for safety properties, like ensuring a counter doesn’t overflow, and liveness properties, such as ensuring that specific signals are stable over time.
Temporal Logic in Property Checking
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Now, let’s dive deeper into how we specify properties. What do you know about temporal logic?
I’ve heard of LTL and CTL. Are those types of temporal logic?
Exactly! LTL helps express properties like 'eventually X will happen,' while CTL can specify 'always A implies B.' These forms are crucial when we talk about property checking.
How do the verification tools use these properties?
The tools exhaustively check these properties against all possible input scenarios, ensuring that our designs behave as expected under any conditions.
Tools for Property Checking
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
What tools do you think are useful for property checking?
I think I’ve heard of Cadence JasperGold.
Yes, JasperGold is one of the most widely used tools. We also have Mentor Graphics Questa Formal and Synopsys Formality. These tools help in verifying various properties with great rigor.
Do they have specific uses?
Absolutely! Each tool offers unique features tailored for different design verification needs, enhancing the overall reliability of our designs.
Real-life Examples of Property Checking
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Let’s look at some practical examples. Can anyone think of a design that benefits from property checking?
A FIFO queue could be checked to ensure that data output is always valid when it’s not empty.
That's a perfect example! The verification tools can check this across all states of the FIFO design.
So, these checks prevent issues in real applications?
Exactly! Ensuring behavior remains correct throughout all scenarios can prevent catastrophic failures in critical systems.
Summary of Property Checking
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
To summarize what we've learned about property checking: it involves verifying expected design behaviors using temporal logic through tools such as JasperGold and Questa Formal.
And it’s crucial for safety and liveness properties!
Correct! Remember, effective property checking significantly enhances our design’s reliability.
Thanks for the insights! I feel like I understand the importance much better now.
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
This section discusses property checking in RTL verification, highlighting its application in ensuring that designs meet defined safety and liveness properties. It explores how formal tools use temporal logic to verify these properties across all potential states of inputs.
Detailed
Property Checking
Property checking is a formal verification technique that verifies whether specific properties or assertions about a design hold true for all possible inputs. Unlike other methods, property checking exhaustively examines a design to ensure that anticipated behaviors are consistently met throughout its operational states.
Key Concepts Covered
- Application: Property checking is particularly crucial in complex designs to verify key properties like safety (for instance, preventing counter overflow) and liveness (ensuring a certain state is reached eventually).
- Working Mechanism: Designers specify behavioral properties using temporal logic forms such as Linear Temporal Logic (LTL) or Computation Tree Logic (CTL), which tools then validate across all potential input scenarios.
- Tools: Prominent tools utilized for property checking include Cadence JasperGold, Mentor Graphics Questa Formal, and Synopsys Formality.
The significance of property checking lies in its ability to validate design reliability, thus reducing the risk of errors in the final product.
Youtube Videos
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Definition of Property Checking
Chapter 1 of 5
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Property checking involves verifying that certain properties or assertions, which describe the expected behavior of a design, hold true for all possible inputs. These properties are generally specified using temporal logic such as Linear Temporal Logic (LTL) or Computation Tree Logic (CTL).
Detailed Explanation
Property checking is a verification method to ensure that specific expected behaviors of a design are met under all circumstances. It uses formal languages, called temporal logic, to describe these behaviors. Linear Temporal Logic (LTL) and Computation Tree Logic (CTL) are examples of such languages that help express how the system should behave over time.
Examples & Analogies
Imagine a school policy stating that 'students must be in class during school hours.' This policy must hold true at all times and for every student. In the same way, property checking examines if the design adheres to its intended rules, ensuring it behaves correctly in every possible scenario.
Application of Property Checking
Chapter 2 of 5
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Property checking is commonly used for verifying complex designs, ensuring that safety and liveness properties are met in an RTL design. For example, it can be used to check that a counter never overflows or that a signal is always stable within a certain time window.
Detailed Explanation
In practical scenarios, property checking is vital for verifying RTL designs. It ensures that safety properties (like preventing overflow in counters) are adhered to, and liveness properties (like ensuring signals remain stable) are maintained throughout the operation of the design. This makes it possible to catch potential failures before they occur in real-world applications.
Examples & Analogies
Consider a traffic light system: we want to ensure that the light never stays red and green at the same time (safety property) and that every light will eventually turn green (liveness property). Property checking assesses whether these rules continually apply.
How Property Checking Works
Chapter 3 of 5
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Designers specify properties such as 'always A implies B' or 'eventually X will happen.' Formal tools exhaustively check if these properties hold for all possible input combinations and timing scenarios.
Detailed Explanation
To perform property checking, designers articulate specific logical properties they expect the design to satisfy. The property 'always A implies B' means that whenever condition A holds true, condition B must also hold. The verification tools then rigorously assess the design, checking every possible input and timing scenario to confirm if these properties are consistently maintained during operation.
Examples & Analogies
Think of a game with strict rules. If a rule states 'if the player has a key (A), they can enter the door (B),' property checking would ensure that this rule holds every time a player with a key encounters the door, no matter when they try to enter.
Tools for Property Checking
Chapter 4 of 5
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Tools: Cadence JasperGold, Mentor Graphics Questa Formal, Synopsys Formality are used for property checking.
Detailed Explanation
There are several specialized tools designed to facilitate property checking. Cadence JasperGold, Mentor Graphics Questa Formal, and Synopsys Formality are among the commonly used ones. These tools automate the process, allowing designers to input their specified properties and receive feedback on whether their designs comply.
Examples & Analogies
Imagine using a software application to check your homework. Just as an app can highlight errors and suggest corrections, property checking tools analyze the design and point out any violations of the stated properties, helping ensure everything functions as intended.
Example of Property Checking
Chapter 5 of 5
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
For a design involving a FIFO (First-In-First-Out) queue, a property might state that 'when the FIFO is not empty, the data output should always be valid.' Formal tools can verify this property across all possible states of the FIFO design.
Detailed Explanation
In this example, the property being checked for the FIFO queue highlights a critical feature: that as long as there is data in the queue, the outputs will be valid (meaning that the data being accessed is accurate). Property checking tools evaluate all possible operational scenarios to ensure this condition is never violated, contributing to reliable system design.
Examples & Analogies
Think of a delivery service. The rule is 'if there are packages in the van (FIFO not empty), they must be properly labeled (data output valid)'. Property checking ensures that regardless of how many packages are loaded or unloaded, every package is always labeled correctly when the van is in use.
Key Concepts
-
Application: Property checking is particularly crucial in complex designs to verify key properties like safety (for instance, preventing counter overflow) and liveness (ensuring a certain state is reached eventually).
-
Working Mechanism: Designers specify behavioral properties using temporal logic forms such as Linear Temporal Logic (LTL) or Computation Tree Logic (CTL), which tools then validate across all potential input scenarios.
-
Tools: Prominent tools utilized for property checking include Cadence JasperGold, Mentor Graphics Questa Formal, and Synopsys Formality.
-
The significance of property checking lies in its ability to validate design reliability, thus reducing the risk of errors in the final product.
Examples & Applications
Verifying that a counter does not overflow when its maximum count is reached, ensuring a safety property is met.
Validating that a FIFO queue outputs valid data whenever it is not empty, confirming its functionality remains correct.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
In the realm of logic, we seek to know, if designs behave, where all inputs flow.
Stories
Once there was a designer who crafted a perfect FIFO queue, but forgot to verify its outputs. One day, it failed to deliver valid data when not empty, leading to chaos in a huge data system. Thus began the journey of using property checking to ensure harmony and reliability.
Memory Tools
Remember 'SLED' for property checking: Safety, Liveness, Exhaustive checks, and Different tools.
Acronyms
For temporal logic, think 'LCT'
'L' for Linear Temporal Logic
'C' for Computation Tree Logic
and 'T' for Time-based properties.
Flash Cards
Glossary
- Property Checking
A process that verifies if certain expected behaviors of a design hold true for all inputs.
- Temporal Logic
A type of formal logic used to describe sequences of states in systems over time, including forms such as LTL and CTL.
- Safety Property
A property stating that something bad will never happen in a system.
- Liveness Property
A property stating that something good will eventually happen in a system.
- Cadence JasperGold
A formal verification tool widely used for property checking, equivalence checking, and more.
Reference links
Supplementary resources to enhance your learning experience.