- Queue in System Verilog is a variable-size, ordered collection of homogeneous objects.
- Queue is similar to one-dimensional unpacked array that grows and shrinks automatically.
- Queues can be manipulated using the indexing, concatenation, slicing operator and equality operators.
- In queue 0 represents the first, and $ representing the last entries.
Queue Operators
0 : Used to represents the first element of queue
$ : Used to represents the last element of queue
{} : Used along with first and last operator to add/delete elements.
Queue Declaration
bit[3:0] data[$];
where:
bit[3:0] -> data_type
data -> name of the queue
$ -> Represents the last element of queue
Queues methods
| Method | Description |
|---|---|
| delete() | It deletes the item at the specified index position. |
| insert() | It inserts the given item at the specified index position. |
| size() | It returns the number of items in the queue. If the queue is empty, it returns as 0. |
| push_front() | It inserts the given element at the front of the queue. |
| push_back() | It inserts the given element at the end of the queue. |
| pop_front() | It removes and returns the first element of the queue. |
| pop_back() | It removes and returns the last element of the queue. |
Queue can be bounded or unbounded
bounded queue – queue with the number of entries limited or queue size specified
unbounded queue – queue with unlimited entries or queue size not specified
Advantage of Queue
- Queue can have variable length, including a length of zero.
- Queue will perform both Last In First Out (LIFO) and First In First Out (FIFO) behavior.
- Queue will have support to adding and removing elements anywhere.