In the fast-paced world of hardware design and verification, efficiency and flexibility are paramount. That’s where the UVM Command Line Processor (CLP) comes in. The CLP is a powerful tool that allows you to optimize the verification timeline in complex design and verification environments, saving you time and effort.
With the UVM CLP, you can provide command-line arguments to run tests with different configurations without the need for recompiling the testbench. This means you can easily experiment with various setups and configurations, enhancing the productivity and shortening the verification cycles.
The UVM_CMDLINE_PROCESSOR class, the backbone of the CLP, provides a range of methods specifically designed to handle command-line arguments. These methods allow you to set UVM variables directly from the command line, controlling components’ verbosity and specifying configurations for integral types and strings.
Whether you are a verification engineer or a designer, the UVM Command Line Processor (CLP) is a valuable asset in your toolbox. It empowers you to navigate the complex world of verification environments with ease, offering efficient testbench reusability and flexibility in configuring the UVM environment.
In the upcoming sections of this article, we will dive deeper into the functionality and usage of the UVM_CMDLINE_PROCESSOR, explore example scenarios, discuss the integration of command-line arguments in SystemVerilog, and highlight the benefits and limitations of this powerful tool.
Table of Contents
UVM_CMDLINE_PROCESSOR Class Methods
The UVM_CMDLINE_PROCESSOR class provides several methods for working with command-line arguments. These methods are essential for efficiently handling and processing command-line arguments in the verification environment.
The UVM_CMDLINE_PROCESSOR class includes the following methods:
- get_inst: This method returns a singleton instance of the UVM command-line processor. It ensures that only one instance of the processor exists throughout the simulation, allowing for easy access and management of command-line arguments.
- get_args: With this method, you can retrieve a queue that contains all the command-line arguments passed to the simulation. It enables you to access and analyze the complete set of arguments provided during test execution.
- get_plusargs: This method provides a queue that specifically captures all the plus arguments passed via the command line. Plus arguments in UVM are prefixed with a ‘+’, indicating additional configuration parameters. The get_plusargs method allows you to identify and handle these specific arguments separately.
- get_uvmargs: You can use this method to obtain a queue that stores all the UVM-specific arguments passed during simulation. UVM arguments are distinct from regular plus arguments and are prefixed with ‘+UVM’. With the get_uvmargs method, you can conveniently access and process these UVM-specific configuration settings.
- get_args_value: This method is particularly useful for extracting specific command-line arguments based on a defined pattern. It searches through the provided command-line arguments and retrieves the first occurrence of an argument that matches the specified pattern. You can then obtain the suffix of the argument, enabling you to extract the desired value or parameter.
Example Usage:
To illustrate the usage of these methods, let’s consider the following scenario:
A verification test class, MyTest, extends the uvm_test class. Within the build_phase function of this test, we can utilize the UVM_CMDLINE_PROCESSOR class methods to handle command-line arguments effectively.
“`systemverilog
class MyTest extends uvm_test;
function void build_phase(uvm_phase phase);
super.build_phase(phase);
// Obtain the UVM_CMDLINE_PROCESSOR instance
UVM_CMDLINE_PROCESSOR clp = UVM_CMDLINE_PROCESSOR::get_inst();
// Retrieve all command-line arguments
queue(string) args = clp.get_args();
// Retrieve plus arguments
queue(string) plusargs = clp.get_plusargs();
// Retrieve UVM-specific arguments
queue(string) uvmargs = clp.get_uvmargs();
// Retrieve the value of a specific argument
string argValue = clp.get_args_value(“myPattern”);
// Use the retrieved values to initialize test variables
// …
endfunction
endclass
“`
In the example above, the MyTest class retrieves and analyzes the command-line arguments using the UVM_CMDLINE_PROCESSOR methods, such as get_args and get_args_value. These methods allow for flexible and efficient handling of command-line arguments within the build_phase function of the test.
By leveraging these UVM_CMDLINE_PROCESSOR class methods, you can seamlessly integrate command-line argument processing into your verification environment, enabling greater configurability and flexibility during simulation.
| Method | Description and Usage |
|---|---|
| get_inst | Returns a singleton instance of the UVM command-line processor. Usage: UVM_CMDLINE_PROCESSOR clp = UVM_CMDLINE_PROCESSOR::get_inst(); |
| get_args | Returns a queue with all command-line arguments. Usage: queue(string) args = clp.get_args(); |
| get_plusargs | Returns a queue with all plus arguments. Usage: queue(string) plusargs = clp.get_plusargs(); |
| get_uvmargs | Returns a queue with all UVM arguments. Usage: queue(string) uvmargs = clp.get_uvmargs(); |
| get_args_value | Finds the first argument that matches a specified pattern and returns the suffix of the argument. Usage: string argValue = clp.get_args_value(“myPattern”); |
Example Usage of UVM_CMDLINE_PROCESSOR
In this section, we will explore an example usage of the UVM_CMDLINE_PROCESSOR class to understand how it can be utilized to handle command-line arguments effectively. Let’s dive in!
Create a Test Class
First, we need to create a test class called my_test which extends the uvm_test class. This test class will serve as an example to demonstrate the usage of the UVM_CMDLINE_PROCESSOR.
Obtain the UVM_CMDLINE_PROCESSOR Instance
To start using the UVM_CMDLINE_PROCESSOR, we need to obtain its instance in the build_phase function of the test. This can be done by calling the get_inst method.
“`systemverilog
function void build_phase(uvm_phase phase);
// Obtain the UVM_CMDLINE_PROCESSOR instance
UVM_CMDLINE_PROCESSOR clp = UVM_CMDLINE_PROCESSOR::get_inst();
// …
endfunction
“`
Retrieve Command-Line Arguments
Once we have the UVM_CMDLINE_PROCESSOR instance, we can retrieve the values of specific command-line arguments using the get_arg_value method. For example, let’s say we have the command-line arguments “+ADDR=” and “+PATTERN=”, which define the address and pattern for our test.
“`systemverilog
function void build_phase(uvm_phase phase);
// Obtain the UVM_CMDLINE_PROCESSOR instance
UVM_CMDLINE_PROCESSOR clp = UVM_CMDLINE_PROCESSOR::get_inst();
// Retrieve the values of command-line arguments
string addr = clp.get_arg_value(“+ADDR=”);
string pattern = clp.get_arg_value(“+PATTERN=”);
// …
endfunction
“`
Initialize Variables in the Test
After retrieving the command-line argument values, we can use them to initialize variables in our test. For example, we can set the address and pattern based on the values obtained from the command line.
“`systemverilog
function void build_phase(uvm_phase phase);
// Obtain the UVM_CMDLINE_PROCESSOR instance
UVM_CMDLINE_PROCESSOR clp = UVM_CMDLINE_PROCESSOR::get_inst();
// Retrieve the values of command-line arguments
string addr = clp.get_arg_value(“+ADDR=”);
string pattern = clp.get_arg_value(“+PATTERN=”);
// Set the address and pattern in the test
my_test.addr = addr;
my_test.pattern = pattern;
// …
endfunction
“`
Example Usage Table
| Command-Line Argument | Description |
|---|---|
| +ADDR=0x1000 | Sets the address to 0x1000 for the test |
| +PATTERN=0xA5A5A5A5 | Sets the pattern to 0xA5A5A5A5 for the test |
Here’s an example of how the command-line arguments can be used:
./simulator +ADDR=0x1000 +PATTERN=0xA5A5A5A5
In this example, the address is set to 0x1000 and the pattern is set to 0xA5A5A5A5 for our test.
By utilizing the UVM_CMDLINE_PROCESSOR class and its methods, we can easily handle command-line arguments and configure our testbench accordingly, providing more flexibility and scalability in our verification environment.
Command-Line Arguments in SystemVerilog
In addition to the UVM_CMDLINE_PROCESSOR class methods, SystemVerilog provides its own system functions for working with command-line arguments. These functions enhance the flexibility and control that developers have over their verification environment. Two important functions are the $test$plusargs and $value$plusargs.
The $test$plusargs function allows developers to search for specific user strings within the list of command-line arguments. It returns a non-zero integer if there is a match, indicating the presence of the specified string in the arguments. This functionality can be leveraged to enable conditional execution of certain parts of the testbench or modify the behavior of the simulation based on command-line inputs.
On the other hand, the $value$plusargs function serves as a means to retrieve the value associated with a particular user string. When a match is found, the function stores the value in a variable, enabling further processing or configuration within the SystemVerilog code. This capability allows for dynamic customization of the simulation based on the provided command-line arguments.
By utilizing these system functions in conjunction with the UVM_CMDLINE_PROCESSOR class methods, developers have powerful tools at their disposal to efficiently handle command-line arguments in SystemVerilog. This combination of features empowers verification engineers to tailor their simulations, enhance reusability, and streamline the verification process.
UVM Set Config Int and String
In addition to the procedural counterparts, the UVM framework also provides command-line arguments for setting configuration values using the +uvm_set_config_int and +uvm_set_config_string options. These arguments allow users to specify configuration settings for UVM components directly from the command line, eliminating the need for manual configuration changes in the code. This provides greater flexibility and ease of use when customizing the behavior of the verification environment.
UVM Set Config Int
The +uvm_set_config_int command-line argument allows users to specify integer-based configuration settings. These settings can be used to control various aspects of the UVM environment, such as the verbosity level of individual components or the configuration of integral types. The value of integer config settings can be specified using base specifiers, providing further customization options for the verification process.
UVM Set Config String
Similar to the UVM Set Config Int argument, the +uvm_set_config_string command-line option enables users to set string-based configuration settings. Strings are commonly used to specify configuration values for UVM components, such as file paths or user-defined settings. By utilizing the +uvm_set_config_string argument, users can conveniently specify these configuration values directly from the command line, simplifying the customization process.
Here is an example of how the +uvm_set_config_int and +uvm_set_config_string command-line arguments can be used:
| Command-Line Argument | Description |
|---|---|
| +uvm_set_config_int | Specifies an integer-based configuration setting. |
| +uvm_set_config_string | Specifies a string-based configuration setting. |
By incorporating the +uvm_set_config_int and +uvm_set_config_string command-line arguments in the UVM verification environment, users can easily customize the behavior of their UVM components without the need to modify the code. This enhances the flexibility and efficiency of the verification process by providing a more streamlined and user-friendly method for configuring the UVM environment.
Controlling UVM with Custom Command Line Arguments
The UVM Command-Line Processor (CLP) provides a powerful means to control the behavior of a UVM simulation using custom command line arguments. With the CLP, users can define and pass their own command line arguments to configure the UVM environment according to their specific needs. This feature enhances the flexibility and adaptability of UVM, allowing for seamless customization and optimization of the verification process.
To utilize custom command line arguments, the CLP employs explicit and regular expression search terms to read and extract individual arguments and their corresponding values from the provided input. This approach provides a highly flexible and intuitive way to interact with the UVM simulation, ensuring that users have full control over the configuration and behavior of their verification environment.
By incorporating custom command line arguments, engineers can fine-tune their UVM simulations without the need for recompilation or modifying the testbench code. This streamlines the verification process and enables rapid exploration of different scenarios and configurations, ultimately leading to more efficient and effective verification efforts.
Example Usage
To illustrate the utilization of custom command line arguments, let’s consider a hypothetical scenario where we want to control the verbosity level of specific UVM components during a simulation. We can define a custom command line argument, such as “-verbosity”, and assign different values to it based on our requirements.
Here’s an example of how we can use custom command line arguments with the CLP to control the verbosity level of a UVM component called “my_component”:
| Command Line Argument | Description |
|---|---|
| -verbosity | Specifies the verbosity level for the “my_component” instance |
By passing different values for the “-verbosity” argument during the simulation, we can dynamically adjust the verbosity of the “my_component” instance, allowing us to gather more detailed information or reduce the output noise as needed.
This example demonstrates how custom command line arguments and the CLP facilitate the seamless customization of the UVM environment, providing engineers with the ability to control and tailor the simulation behavior according to their specific requirements.
Limitations of UVM_CMDLINE_PROCESSOR
While the UVM_CMDLINE_PROCESSOR is a powerful tool for configuring the UVM environment with command-line arguments, it does have some limitations. One limitation is that there is no equivalent of the set_config_object method, as there is no way to pass a uvm_object into the simulation via the command line. This means that configuration of uvm_objects must be done through other means.
Benefits of Using UVM_CMDLINE_PROCESSOR
The UVM_CMDLINE_PROCESSOR offers several benefits for verification environments. Let’s explore the advantages it brings:
- Optimization of the Verification Timeline: The UVM_CMDLINE_PROCESSOR allows for the optimization of the verification timeline by avoiding testbench recompilation. This can save significant time and effort, especially in large and complex designs.
- Flexibility in Configuring the UVM Environment: With the UVM_CMDLINE_PROCESSOR, it becomes easy to experiment with different configurations in the UVM environment. By providing command-line arguments, it enables users to quickly modify settings without the need for extensive code changes.
These benefits contribute to enhanced efficiency and productivity in verification tasks, making the UVM_CMDLINE_PROCESSOR an invaluable tool for verification engineers.
As we can see, the UVM_CMDLINE_PROCESSOR empowers verification engineers to optimize their workflow and achieve faster results. Now, let’s dive deeper into the usage and capabilities of the UVM_CMDLINE_PROCESSOR class methods.
Conclusion
The UVM Command Line Processor (CLP) is a valuable tool for optimizing the verification timeline and providing flexibility in configuring the UVM environment. With the ability to use command-line arguments, the CLP enables testbench reusability and efficient exploration of different configurations. This enhances productivity and shortens verification cycles, saving time and effort in complex design and verification environments.
Throughout this article, we explored the various methods of the UVM_CMDLINE_PROCESSOR class and witnessed its effective handling of command-line arguments. The example usage demonstrated how the CLP can be utilized to create and initialize test variables based on command-line inputs. By leveraging the power of the UVM_CMDLINE_PROCESSOR, verification teams can optimize testbench configurations and swiftly adapt to different requirements.
Overall, the UVM_CMDLINE_PROCESSOR is a powerful asset in the field of hardware verification. From its ability to streamline the verification timeline to its capacity for easy configuration manipulation, this tool provides essential functionality for enhancing efficiency and productivity. By harnessing the power of the UVM_CMDLINE_PROCESSOR, verification engineers can effectively control and adapt their UVM environment, ultimately delivering high-quality designs.
