System Verilog
System Verilog Introduction
Last Updated: May 4, 2025What is System Verilog : Introduction to system verilog SystemVerilog is a Hardware Description and Verification Language based on Verilog. Although it has some features to assist with design, the thrust of the language is in verification of electronic designs. The bulk of the verification functionality is based on the OpenVera language donated by Synopsys....
Data Types
Last Updated: May 4, 2025System Verilog Data Types Overview :1. Integer or Basic Data Types – System verilog has a hybrid of both verilog and C data types shortint – 2-state SystemVerilog data type, 16-bit signed integerint – 2-state SystemVerilog data type, 32-bit signed integerlongint – 2-state SystemVerilog data type, 64-bit signed integerbyte – 2-state SystemVerilog data type, 8-bit signed integer or ASCII...
Type Casting
Last Updated: May 4, 2025Share This Articale: Type Casting In System Verilog :Many Times we require assigning one type of variable to other type variable. Verilog was loosely typed language. The variables could be assigned to other type without any implicit casting. But with system verilog we need to manually cast the variable from one type to the other...
Arrays
Last Updated: May 4, 2025Arrays in system verilog : An array is a collection of variables, all of the same type, and accessed using the same name plus one or more indices. reg [7:0] r1 [1:256]; // [7:0] is the vector width, [1:256] is the array size SystemVerilog uses the term packed array to refer to the dimensions declared before...
Associative Arrays
Last Updated: May 4, 2025An Associative array is a better option when the size of the collection is unknown or the data space is sparse. So the associative arrays are mainly used to model the sparse memories. In the associative arrays the storage is allocated only when we use it not initially like in dynamic arrays. Associative arrays can be...
Dynamic Arrays
Last Updated: May 4, 2025Dynamic arrays are fast and variable size is possible with a call to new () function. In dynamic size array : view source print? 01.module example; 02. 03.reg [31:0] regArray_1[]; 04.reg [31:0] regArray_2[]; 05.reg [31:0] regArray_3[]; 06.reg [31:0] regArray_[]; 07. 08.int i; 09. 10.initial 11.begin 12.regArray_1 = new [5]; 13.regArray_3 = new [3]; 14.regArray_ = new [10]; 15. 16.// initialize values for regArray_1...
Queue
Last Updated: May 4, 2025In queues size is flexible. It can change easily A Queue is a variable size ordered collection of homogeneous objects. There are two main aspects of a queue that makes it attractive for verification purposes. First, a queue can have variable length, including a length of zero. This makes a queue an ideal candidate as...
Operators
Last Updated: May 4, 2025Operator Type Operator Symbol Operation Performed Arithmetic * Multiply / Division + Add – Subtract % Modulus + Unary plus – Unary minus Logical ! Logical negation && Logical and || Logical or Relational > Greater than < Less than >= Greater than or equal <= Less than or equal Equality == Equality != inequality Reduction...
Procedural statements and Control flow
Last Updated: May 4, 2025A procedural statement can be added in system verilog using : SystemVerilog has the following types of control flow within a process:— Selection, loops, and jumps— Task and function calls— Sequential and parallel blocks— Timing control Blocking and Non Blocking Statement : Following type of statement is allowed in both verilog and system verilog. view...
Classes
Last Updated: May 4, 2025Classes contains properties and methods. Methods perform operations on the class properties. Class name will be used as type to declare the variable or handle for the class.Instance for the class is created with the constructor which is new method. When you call the new method memory is allocated to class and its properties. If...
Inheritance
Last Updated: May 4, 2025Class Inheritance In System Verilog : A class declaration can extend an existing class. Inheritance Subclass inherits all members of parent.Can over-ride parent’s members Parent members are accessed as if they were members of the subclass view source print? 01.class parent; 02.logic [3:0] avec; 03.logic abit; 04. 05.function void print(); 06.$display("%d %d", avec, abit); 07.endfunction 08. 09.endclass 10. 11.class child extends parent; 12.int avec; ...
Encapsulation
Last Updated: May 4, 2025In system verilog all the properties of the class are public by default or we can say it be accessed outside the class directly using the dot operator. If we want to protect the access of the class variables/properties from outside the class we can use the local keyword. Hiding the properties from being accessed outside the...
This and Super operator
Last Updated: May 4, 2025this is a handle to the current class object. Useful for accessing class members re-declared within a local scope super is a handle to the parent class object. Essential for accessing parent class members hidden in subclass For example, constructor Only 1 super allowed at a time. super.super.new() is illegal. The existence of a parent...
In-Line Constraints
Last Updated: May 4, 2025One of the main feature of the systemverilog classes are randomization. You can randomize the system verilog classes with the randomize method using obj.randomize(); It will randomize all the properties which are declared as rand and randc and can take any valid value for the varialbe. like for variable rand bit [3:0] a; A can...
Class Constraints
Last Updated: May 4, 2025Constraints can be declared as class properties. Constraints can enforce dependencies for randomization. Dynamic array is now rand. Both size and contents are randomized, but… …size is randomized first post_randomize and data_rand methods are no longer required. 01.class randframe; 02.local logic [3:0] addr; 03.rand local logic [3:0] len; 04.rand logic [7:0] data_arr []; 05. 06.function new(input logic[3:0] pa); 07.addr = pa; 08.endfunction 09. 10.constraint framelength...
Virtual Classes
Last Updated: May 4, 2025A virtual class is a temple or place holder for the child classes. A virtual class is also called as the abstract class. A virtual class is declared with a virtual keyword like : virtual class base; endclass; A virtual class instance or object can not be constucted but you can define the hadle to...
Parameterized Classes
Last Updated: May 4, 2025System verilog allows prameterized classes. In the system verilog you can parameterize the types also. Its basically like templates in C++. Like in classes can be parameterized for size, width, and more With Verilog parameter notation Class type can also be a parameter – Qualified with keyword type – Define operations which can...
Singleton Classes
Last Updated: May 4, 2025Sometimes it is required to have only one object of some classes like configuration classes. For this purpose we create singleton classes. Only one object is created for a singleton class and whenever we try to create a new object, same object is returned. System verilog does not provide construct to create a singleton class....
Functional Coverage Introduction
Last Updated: May 4, 2025Coverage is defined as the percentage of verification objectives that have been met. It is used as a metric for evaluatingthe progress of a verification project in order to reduce the number of simulation cycles spent in verifying a design. There are two type of the coverage metrics code coverage and functional Code coverage and...
Covergroup
Last Updated: May 4, 2025Covergroup is like a user defined type that encapsulates and specifies the coverage. It can be defined in a package, module, program, interface or class Once defined multiple instances can be created using new Parameters to new() enable customization of different instances. A covergroup sepcification can include the following components – Ref argument enables different...
Tools
Last Updated: May 4, 2025Simulators IDE : Free Simulators : Only Verilog 1995 VCD Viewer nWave: One of the best VCD viewer, with support for large VCD dumps. Undertow: Undertow waveform viewer. GTKWave: Freeware VCD viewer, Seems far better then other free VCD viewers. Dinotrace: Freeware VCD viewer from veritools Code Coverage Linting Leda: Leda is a code purification...
Books
Last Updated: May 4, 2025Few Good books on system verilog I know are :1. System verilog LRM2. System verilog for verification : Chris Spear3. System verilog for design