uvm_pool and semaphore 101. sv & uvm_pkg. S. UVM has a rich reporting facility. TYPE’s constructor, if defined, must have default values on all it arguments. `uvm_object_param_utils_begin. Uvm_env. The UVM class library provides the basic building blocks for creating verification data and components. A message with the UVM_NONE level is. There is often a need to copy, compare and print values in these classes. Deploying Parameterized Interface with UVM Wayne Yun AMD, Inc. It performs a deep copy. The next step is to have the a UVM component grab the parameters from the configuration object. Main concepts of UVM (1) • Clear separation of test stimuli (sequences) and test bench –Sequences are treated as ‘transient objects’ and thus independent from the test bench construction and compositionHow to use the UVM configuration facility? Configuration values are set in the uvm_config_db class using the set() method and retrieved using the get() method. This article explains how to use a verbosity threshold to filter messages. By applying stimulus to the register model, the actual design registers will exhibit the changes applied by the stimulus. 0 ‐ Their Use in Verification and UVM The prototype of the virtual function in Figure 1 is the header code: virtual function bit do_compare (uvm_object rhs, uvm_comparer comparer); This virtual method prototype includes five required elements: (1) the return type is bit, (2) theIn Introduction, we saw that most of the verification components are inherited from uvm_report_object and hence they already have functions and methods to display messages. ), which extends from uvm_object, benefit from using uvm utility macros (`uvm_component_utils, `uvm_object_utils)? As I understand, `uvm_component_utils and `uvm_object_utils are used to register a class w/ the factory so objects of that class can be over. 02. The uvm_component_registry class extends uvm_object_wrapper and implements its create_component() function, but it also has many other functions related to registering itself with the factory and handling type overrides. When used as a base for user-defined RegModel test sequences, this class provides convenience methods for reading and writing registers and memories. Blocks. UVM Phases. Its primary role is to define a set of methods for such common operations as create , copy, compare, print, and record . You can create an uvm_event. Then you can do: typedef uvm_object_registry# (abc_test_seq,`STR (`SEQ_NAME (abc))) type_id;. That is different from the strategy that you might choose in order to drive signals. uvm_reg_block. But, virtual_sequence and virtual_sequencer do not require any virtual keyword. 1. H. 1. Say the object is "my_tb". Using do_record. 1에서는 uvm_object에 대한 constructor가 필수 사항이 아니었지만, UVM 1. It also becomes easier to connect to design regardless of the number of ports it has since that information is encapsulated in an interface. uvm event callbacks are an alternative to using processes that wait on events. Try these examples yourself. The monitor captures values on the DUT's input and output pin. This class will also need to be able to get information from the config_db using hierarchical paths, and plain old uvm_objects don't have hierarchy. Yes, the UVM create() method calls new() constructor on the object without any arguments (string name is not passed in there). It is an abstract class with no data members or functions. On calling `uvm_do () the above-defined 6 steps will be executed. Divide the DB into smaller domains by grouping values into config objects. UVM_Object. We would like to show you a description here but the site won’t allow us. uvm_pool allow us to store any type of data with a key as index, similar to an associative array. I have two class handles inside my sequence item. As you say, the UVM field automation macros generate a number of class utility methods such as copy, print and clone that include the registered fields. The first three methods above take uvm_object_wrapper as their type argument (s). `uvm_do (Item/Seq) This macro takes seq_item or sequence as argument. So all you need to do is remove the type E parameter declaration. UVM Heartbeat Usage. uvm_object - Data structures for testbench configuration; uvm_transaction - Stimulus generation & analysis; The values of the arguments of new method are used to create an entry in a linked list which the UVM uses to locate uvm_components in a pseudo hierarchy, this list is used in the messaging and configuration mechanisms. zhang@amd. As I understood for all items inherited from uvm_component, they all need uvm_component parent as part of constructor input argument. 02. It allows for generic containers of objects to be created, similar to a void pointer in the C programming language. The driver receives the item and drives it to the DUT through a virtual interface. A policy object can be passed along to set parameters like depth of comparison, verbosity, maximum number of. In the case of UVM based System Verilog testbench, class objects can be created at any time during the simulation based on the requirement. If you use the uvm_top. Use uvm_config_db# (uvm_object)::set. 1-289-695-1969 shihua. This behavior is called “overriding” and there are 2 types of overriding is possible with UVM Factory (described below). Using do_pack/do_unpack. e. the uvm_event class makes it easy by providing uvm_event_pool. UVM tutorial for beginners Introduction Introduction to UVM UVM TestBench TestBecnh Hierarchy and BlockDiagram UVM Sequence item Utility & Field Macros Methods with example Create Print Copy Clone Compare Pack UnPack UVM Sequence Sequence Methods Sequence Macros Sequence Example codes UVM Sequence control UVM. pyuvm uses cocotb to interact with the simulator and schedule simulation events. Uvm factory is one of the most notable term when using uvm methodology. 1. event_object event_object_h; uvm_object temp_obj; . The primary purpose of a function is to return a value that can be used in an expression and cannot consume simulation time. e. This is applicable for uvm objects and components. answered Sep. The scope of the randomize() object is the this argument inside. The print method is used to deep print UVM object class properties in a well-formatted manner. Follow. CB – user-defined callback type. A memory is a collection of contiguous locations. The user can simply apply a different. package my_stuff; `include "Packet. UVM uses the concept of a factory where all objects are registered with it so that it can return an object of the requested type when required. It does a deep comparison. You can use the uvm_object_registry (T,S) or uvm_component_registry (T,S) registration macros. UVM Factory is a standardized mechanism to create different objects. Using UVM in SystemC is a tutorial paper that presents the benefits and challenges of applying the Universal Verification Methodology (UVM) to SystemC-based verification environments. You can think of any method call as having an implicit this argument. 이때 아래의 그림과 같이 agent내부에서는 어떤 configuration이 uvm_config_db를 통하여 설정됨을 가정하여 get ()으로. UVM components support logging with the following steps. 09. wait_ptrigger_data. In order to understand the different role that the Accellera Portable Test and Stimulus (PSS) standard plays versus UVM, let's consider this brief statement about what PSS is intended to accomplish, taken from the 1. We’ve already talked about how the factory uses uvm_object_wrappers to perform the actual creation and maps type names to such objects. 01 Building blocks in SystemVerilog 01. These macros are used to start sequences and sequence items on default sequencer, m_sequencer. essentially take the current global id then increment the counter. This is useful when you want to affect the with in a particular uvm_object can can be made scalable by overriding the do_print() method. raise_objection (uvm_object obj = null, string description = ” “, int count = 1) Raises number of objections for corresponding object with default count = 1. If no argument is specified (or an argument. Using Callback. 01 SystemVerilog Testbench 구조 01. factory. This code follows the convention that member variables start with the prefix of. UVM TestBench to verify Memory Model. It is an abstract class with no data members or functions. so when you print the object right after its construction you both should be almost the same. This method calls uvm_event_base::wait_trigger followed by get_trigger_data. Teams. In our case, two uvm_queues are created; one for the "jb_if1" and the other for the "jb_if2". uvm_env is used to create and connect the uvm_components like driver, monitors , sequeners etc. We use uvm_config_db::set to put something into the database and uvm_config_db::get to retrieve information from the database. UVM TestBench to verify Memory Model. UVM Debugging features. You should create a new macro that add quotes around it input argument. Some Standard Data Methods of the uvm_object Class By now you might think that these field macros are convenient but not efficient. uvm_transaction and uvm_component are also derived from uvm_object. 总结：在多进程IP中，寄存器模型 中参数uvm_object extension的使用可以极大的方便验证工程师的工作。. Share. The uvm_object_wrapper provides an abstract interface for creating object and component proxies. The recommended method in UVM for creating components or transaction objects is to use the built-in method::type_id::create () instead of calling the constructor new () directly. uvm_component provide a set of convenience functions that call the uvm_factory member functions with a simplified interface. As the name suggests, it keeps a track of the sequences that are registered with it, and calls them a number of times in a random fashion. ; Once you convert your testbench from passing individual values to passing config objects, you can see the bigger picture, which is that a testbench is configured and built from the top down, guided by the configuration. When the component (my_monitor) calls analysis_port. Its intention is to print the name of the type of a given object instance. virtual function uvm_object. After all, you just set the value of data and id with the name “t1”. Agent includes a UVM sequencer to manage stimulus flow, a UVM driver to apply stimulus to the DUT interface, and a UVM monitor to monitor the DUT interface. uvm_object. Alternatively, if the change is intended to be global, there is a default printer that automatically created at root called uvm_default_printer . First, let's. Set the default sequencer that should execute this sequence. This can be useful for peak and off-peak times. Each resource has a set of scope. get_trigger_data. After the utility macro are the field automation macros in the form ‘uvm_field_*(data member, flag). Implementations of uvm_object::do_pack and uvm_object::do_unpack should regard this bit when performing their respective operation. These Subtypes include uvm_printer, uvm_line_printer, uvm_tree_printer, uvm_table_printer. If no constructor is specified, a default constructor is. Conclusion. Objects of this type will be used by sequences. The handle to the uvm_resource object is stored in two kinds of uvm_queues. The primary role of uvm_object class is to define a set of common utility functions like print, copy, compare and record which can be availed by any other class in a UVM testbench to save effort. It is the base class for all UVM data and hierarchical classes. All the signals listed as the module ports belong to APB specification. This section defines the proxy component and object classes used by the factory. Alternatively, if the change is intended to be global, there is a default printer that automatically created at root called uvm_default_printer . Here is a transaction class. Now we are going to look at the next step, the Universal Verification Methodology (UVM) implemented in Python. 2 Class Reference represents the foundation used to create the UVM 1. They are implemented separately from uvm_object so that users can plug in different ways to print, compare, etc. 2 Comments. We need to plan for it by structuring our code in certain ways. The UVM methodology enables engineers to quickly develop powerful,. As we saw earlier, the jelly_bean_transaction::type_id is a uvm_object_registry type. T(semaphore)) semaphore_pool To get the handle of. 0 and UVM 1. Factory is a centralized location to make calls from look-up tables for creation of any transaction types. Sequences. There are many kinds of design patterns. uvm_env is extended from uvm_component and does not contain any extra functionality. UVM REPORTING The uvm_report_object provides an interface to the UVM reporting facility. Gets the data, if any, provided by the last call to trigger. ; uvm_resource_db is the parent class of uvm_config_db, which is used to set different values in the registry and. 1. The factory is a special class in UVM that creates an instance for you of whatever uvm_object or uvm_component type you specify. Class Hierarchy. uvm_object is basically the main class. `uvm_create (Item/Seq) This macro creates the item or sequence. In a previous article , print, do_print and use of automation macros to print were discussed. Factory is a singleton object and there is only one instance of the factory in a UVM environment. 3. UVMObject. uvm_mem. 2 Class Reference represents the foundation used to create the UVM 1. Please see Register Abstraction for how each property is packed. UVM also introduces a bunch of automation mechanisms for implementing print, copy, and compare objects and are defined using the field macros. For transactions, the typical constructor is shown in Example 2. It is the base class for all UVM data and hierarchical classes. You should create a new macro that add quotes around it input argument. The uvm_event class is directly derived from the uvm_object class. Such a. 1. Supposed that your component name is "comp" in ENV, and the env is named "env" in the uvm_test, so in test bench top module, you should use below code to get the configuration handle. randomize() are the same method call. Here are the general steps to create and use a register. You can use the uvm_object_registry (T,S) or uvm_component_registry (T,S) registration macros. This concept is widely used in UVM, especially the uvm_config_db configuration database. Share. 1-289-695-1968 wayne. data = 2; t1. I found having parameters in uvm_object/uvm_componet is handy in some case, but I know some one think it is a bad idea. 3. `uvm_field_utils_begin. In create method, we have to construct a new object of configuration class and update all the important fields and return it. The utils macros define the infrastructure needed to enable the object/component for correct factory operation. Create uvm_object base class. The document covers the UVM 1. 0a version of the standards document: “The goal is to allow stimulus and tests, including coverage and results checking, to be. There are two branches in the hierarchy : Under uvm_component: Classes that define verification components like driver, monitor and agents. Yes, each component’s run_phase is executed in a separate process. In order to use the factory, to create or override an object/component, all the object and component classes must be registered with the factory. Note: The factory override ways are applicable for both uvm components and uvm objects. Yes, the UVM create() method calls new() constructor on the object without any arguments (string name is not passed in there). 2-2017. FollowSimple (non-parameterized) objects use the uvm_object_utils* versions, which do the following: Implements get_type_name, which returns TYPE as a string; Implements create, which allocates an object of type TYPE by calling its constructor with no arguments. answered Jun 19, 2014 at 23:32. e. Refer to “Macros” in the UVM 1. The UVM class library provides the basic building blocks for creating verification data and components. Add a comment. set_type_override_by_name ("base_sequence",`STR (`SEQ_NAME (abc))); In. The uvm_object_registry has static methods, which you call with the class::type_id::create() syntax. An appropriate `uvm_field_* macro is required to use based on the data type of class properties. It is an abstract class with no data members or functions. 7,483 1 1 gold badge 25. pyuvm is the Universal Verification Methodology implemented in Python instead of SystemVerilog. If user wants to run a test with PCIe speed = Gen2 and lanes = x2, then this can be achieved simply by having +link_speed=gen2 and +lanes=2 on command line arguments, and in verification. Please see Register Abstraction for how each property is packed. But that's another debate. uvm_component like uvm_driver is always connected to a particular DUT interface because throughout the simulation its job is fixed i. The run_phase is a thread started automatically by the UVM core. uvm_config_db#(TYPE)::set(this,"*. In UVM, is there anything in the uvm_object::compare method or uvm_comparer policy to implement a different comparison similar to the VMM compare() kind argument? For example, I would like a mechanism to be able to select between doing a full compare of all object members or a partial subset compare. We would like to show you a description here but the site won’t allow us. These macros can appear anywhere in the declaration space of the class declaration of T and will associate the string S to the object type T. How to use UVM Factory. This class will also need to be able to get information from the config_db using hierarchical paths, and plain old uvm_objects don't have hierarchy. Such a configuration database allows us to store different configuration settings under different names. class tx_item extends uvm_sequence_item;. Here is my thought/search process: I've found that uvm_factory class has a register method which registers a proxy object of a given type. A block represents a design hierarchy. ; The user-defined subscriber is derived from uvm_subscriber that must define the write method (A write method is a pure virtual method that is declared in the uvm_subscriber class). uvm_config_dbに渡すパラメータタイプはuvm_object_wrapperになります。これはuvm_config_dbにtypeを登録する場合の型です。 第一引数は通常はthisです。 第二引数は対象となるシーケンサのUVMの階層名+フェーズ名になります。From the application point of view, UVM Factory facilitates an object of one type to be substituted with an object of derived type without having to change the structure of the Testbench or modify the Testbench code. 4. Multiple recipients accessing an object via get(), will access the same object. 02. Then the UVM test bench utilizes virtual interfaces at dynamic driver, monitor class to access static interfaces [3], it retrieves the bind interface instance handle by reading uvm_resouce_db: Figure 2 – connect RTL and UVM by interface bind uvm_pkg::uvm_resource_db#( virtual svt_axi_slave_if)::read_by_name. You need a uvm_sequencer with seq_item_export to connect to the driver's seq_item_port. This is applicable for uvm objects and components. KEY(int),. System Verilog has virtual methods, virtual interfaces, and virtual classes. Is there a command-line command to change the verbosity for a uvm_object (like a configuration object)? For components, I use: +uvm_set_verbosity=test_top. Requirements. . The uvm_subscriber is derived from uvm_component and adds up the analysis_export port in the class. The clone method calls the create() method followed by copy(). Not sure how that is going to help. With Easier UVM, configuration parameters should be accesed by calling uvm_config_db # (T)::get. uvm_component provide a set of convenience functions that call the uvm_factory member functions with a simplified interface. // For example, "set_type_override_by_type" is actually a function defined in the class uvm_factory // A wrapper function. task body; i2c_packet pkt; pkt = i2c_packet::type_id::create("pkt"); pkt. The uvm_object class is the base class for all UVM data and hierarchical classes. Nearly all UVM classes are extended from uvm_object. The UVM is completely described in the IEEE 1800. In a type override, a substitute component class type is created instead of an original component class in the testbench hierarchy. The factory (or to be precise, uvm_component_registry) will call new on behalf of you. 2) from Accellera. class uvm. Every class item derived from uvm_object will have a printer instance within it. The clone () method was declared in uvm_object and returns a handle of type uvm_object. id = 42; At this point you might be tempted to call the object “t1”. UVM_WARNING @ 0: reporter [TPRGED] Type name 'packet2mem_comp_Str' already registered with factory. typedef uvm_object_string_pool #(uvm_event #(uvm_object)) uvm_event_pool; We’ll go in detail of uvm_pool in another post. Constraints may be added via inheritance in a derived class. A cleaner implementation would have been for uvm_component_registry to be its own class, that doesn’t extend uvm_object_wrapper, that instead creates an instance of a uvm_object_wrapper and registers it with the factory instead of itself. The most common UVM macros are: uvm_component_utils: registers a new class type when the class derives from the class uvm_component; uvm_object_utils: similar to uvm_component_utils, but the class is derived from the. argument object. It also becomes easier to connect to design regardless of the number of ports it has since that information is encapsulated in an interface. Interfaces can contain tasks, functions, parameters, variables, functional coverage, and assertions. It is intended for verification engineers who want to use UVM 1. First, let's. 1. pyuvm uses cocotb to interact with the simulator and schedule simulation events. Step #1: Create a base callback class. UVM 1. PyUVM Description. If you are using OVM/UVM then get_full_name() / get_name() will return the name of the component in the testbench hierarchy. All the signals listed as the module ports belong to APB specification. Classes deriving from uvm_object must implement the pure virtual methods such as create and get_type_name. A block has one or more address maps, each corresponding to a physical. Using macros like `uvm_do , `uvm_create, `uvm_send etc; Using existing methods from the base class a. I can't use a generate loop inside the class and I couldn't find out a way to use a for loop to pass the individual parameters. macro: Can be used, but try to avoid if you are. The important thing to remember is that each entry needs a unique field name or label (if the global scope is being used), or the path needs toThese macros are used to start sequences and sequence items on default sequencer, m_sequencer. Is this achievable in UVM 1. A cleaner way would be to use the sequence library provided by UVM as uvm_sequence_library. To implement some important methods in classes and variables, UVM provides the UVM Macros. Print method; Copy and clone methods; Compare method; Pack / Unpack methods; Resource database in UVM. It is then placed into the configuration database using uvm_config_db so that other testbench components within this environment can access the object and configure sub components accordingly. 2 uvm_object constructor. The UVM application programming interface (API) defines a standard for the creation, integration, and extension of UVM Verification Components (UVCs) and verification environments that scale from block to system. sv is included. 02. UVM tutorial for beginners Introduction Introduction to UVM UVM TestBench TestBecnh Hierarchy and BlockDiagram UVM Sequence item Utility & Field Macros Methods with example Create Print Copy Clone Compare Pack UnPack UVM Sequence Sequence Methods Sequence Macros Sequence Example codes UVM Sequence control UVM. path","label",value) (Adding other objects into the uvm_config_db is just as straightforward as adding a virtual interface. path","label",value) (Adding other objects into the uvm_config_db is just as straightforward as adding a virtual interface. uvm_object is the main class in which common functions to print, copy, and compare two objects of the same class are defined. Then you can do: typedef uvm_object_registry# (abc_test_seq,`STR (`SEQ_NAME (abc))) type_id;. UVM_Object: uvm_object is basically the main class. by The Art of Verification. print() routines you get what you expect. After the utility macro are the field automation macros in the form ‘uvm_field_*(data member, flag). The uvm_object or sequence overriding is similar to the uvm_component overriding factory mechanism that returns the derived object handle using a base class handle. The constructor of uvm_component adds a uvm_component parent argument which is used to create. 用途は、UVMの「オートメーション」機能を適用するために使います。. It is an abstract class with no data members or functions. The handle to the uvm_resource object is stored in two kinds of uvm_queues. For example, if the knobs says we're in a certain mode, and the sequence shall be constrained according to the mode, then the knobs must be available at sequence pre/post/randomize(), it is too late to read them from a. Better yet, don't use any field macros at all as they are horribly inefficient. Phases : UVM defines a set of simulation phases that enable users to control the order in which testbench components are created, initialized, and executed. Before moving to uvm_sequence_item will look into uvm_object concepts required to write uvm_sequence_item, The uvm_object has a number of virtual methods that are used to implement common data object functions (copy, clone, compare, print, transaction, and recording) and these should be implemented to make the sequence_item more general purpose. sv" into the same package you probably need to import the package where monitor. This is not a complete design since our purpose is simply to show how registers in this design can be read/written using a UVM register model. The first kind of queues store the handles to the uvm_resource objects that have the common field_name. 2, the UVM object factory now requires that uvm_object have a constructor. 613. We would like to show you a description here but the site won’t allow us. Users can create/use packers anywhere in their code, not just in the context of a UVM object. It serves an important role to define a set of methods such as create, copy, print, clone, compare, record, etc. build_phase (phase) must be called in the. uvm_comparer is the standalone class used to set a policy for doing comparisons and determines how miscompares are counted. There is often a need to copy, compare and print values in these classes. Follow edited Apr 23, 2014 at 8:00. 06 Array Operators and Methods. endclass This means that our long list of assignments that the copy expands to would also contain: copy. Hence, it is required to have proper synchronization to avoid objects/components being called before they are created, The UVM phasing mechanism serves the purpose of synchronization. The paper explains how UVM can be integrated with SystemC using the UVM-ML Open Architecture, a framework that enables interoperability between different. The record function takes a recording policy object as the argument (line 14). The `name` input is used for purposes of storing and printing a miscompare. 1. 2 Class Reference is independent of any specific design processes and is complete for the construction ofThe UVM 1. Imagine a UVM sequence generating 20-25 SIZED Ethernet packets followed by a PAUSE packet followed by 30-40 QTAGGED packets. UVM Object and UVM Component. It allows for generic containers of objects to be created, similar to a void pointer in the C programming language. e. The lack of typing means a lack of parameterized ports, exports, and uvm_tlm_fifos. If we were to have a variable of type uvm_object (where get_type_name is first defined), we could store. There are two ways to register an object with the UVM factory. Because phases are defined as callbacks, classes derived from uvm_component can perform useful work. UVMFactory is used to create objects of type UVMComponent and UVMObject (and their derived user-defined types). After new'ing , it uses set_name() to assign the appropriate value to the name string. This section defines the proxy component and object classes used by the factory. But, virtual_sequence and virtual_sequencer do not require any virtual keyword. A utils macro should be used inside every user-defined class that extends uvm_object directly or indirectly, including uvm_sequence_item and uvm_component. The uvm_object provides methods like create, clone, copy, record, compare, print, etc. Your sequence would have, instead of an array of pixels, an array of ints, and then you could transform from/to in the driver and monitor. e it is allowed to send the transaction Only after consumption of the previously sent transaction, in this case, the sender and receiver must be in sync else. randomize with {…} or `uvm_do_with) permit specifying additional constraints when randomizing an object. In this page, we'll try to execute a sequence item using the start_item/finish_item task. The important thing to remember is that each entry needs a unique field name or label (if the global scope is being used), or the path needs to 1 Answer. Objects are dynamic, so implicitly the question you are asking is invalid. `uvm_field_utils_end. myagent. Class Hierarchy Class Definition See full list on chipverify. `uvm_object_param_utils(TYPE) For parameterized objects, with field macros, use `uvm_object_param_utils_begin(TYPE) `uvm_field_* macro invocations here `uvm_object_utils_end Simple (non-parameterized) objects use the uvm_object_utils* versions, which do the following: Implements get_type_name, which returns TYPE as a. 02. 02. drop_objection (uvm_object obj = null, string description = ” “, int count = 1) Drops number of objections for corresponding object with default count = 1uvm_object is the main class in which common functions to print, copy, and compare two objects of the same class are defined. `uvm_create (Item/Seq) This macro creates the item or sequence. Unfortunately this wont work yet because we have to register seq_item as follows `uvm_object_param_utils(seq_item#(A)). 08 Subroutines 01. 06 Array Operators and Methods 01. TYPE’s constructor, if defined, must have default values on all it arguments. 1 min read. UVM configuration provides. The word “factory” in UVM refers to the substitution of any object or component in the verification environment without modifying any part of code in any testbench. class my_driver. uvm_object is the one of the base classes from where almost all UVM classes are derived. This flexibility allows comprehensive testing of different configurations using a single, reusable testbench, significantly reducing development time and effort. The UVM heartbeat can detect simulation hang or lock-up conditions at an early stage rather than the expiry of the global simulation timeout. . They allow access to the functions copy, compare, pack, unpack, record. Accellera UVM Tutorial 2016 is a comprehensive presentation that covers the basics and advanced features of the Universal Verification Methodology (UVM), a standard framework for creating reusable and portable verification components and environments. Stimulus는 아직 작성하지 않고, testbench 골격만을 작성해 봅니다. This guide is a way to apply the UVM 1.