Popback 2354 data 1 data qint popfront 354 data 2

data = q_int. pop_back (); // {2,3,5,4} data = 1
data = q_int. pop_front (); // {3,5,4} data = 2
while (q_int. size() > 0) // checking queue size
data = q_int. pop_back() ; // loop executes 3 times
q_bit. push_front (8’h01); // {’h01}
q_bit. push_back (8’h45); // {’h01,’h45}
q_bit. push_front (8’h89); // {’89,’h01,’h45}
end
Queue methods support inserting and extracting elements. This example illustrates use of
several of the methods.
Pause here and examine this example using queue methods.

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Queue Indexing Example
int q_int [$] ; // queue declaration syntax
bit [7:0] q_bit [$:100] ; // queue with maximum size of 100
initial begin
q_int = {0,q_int}; // {0}
q_int = {q_int,1}; // {0,1}
q_int = {2,q_int}; // {2,0,1}
q_int = {q_int[0],3,q_int[1:$]}; // {2,3,0,1}
q_int = {q_int[0:2],4,q_int[3]}; // {2,3,0,4,1}
q_int = {q_int[0:1],q_int[3:4]}; // {2,3,4,1}
q_int = {q_int[0:1],5,q_int[2:3]}; // {2,3,5,4,1}
data = q_int[$]; q_int = q_int[0:$-1]; // {2,3,5,4} data = 1
data = q_int[0]; q_int = q_int[1:$]; // {3,5,4} data = 2
while (q_int. size() > 0) begin // checking queue size
data = q_int[$]; // loop executes 3 times
q_int = q_int[0:$-1]; end
q_bit = {8’h01,q_bit}; // {’h01}
q_bit = {q_bit,8’h45}; // {’h01,’h45}
q_bit = {8’h89,q_bit}; // {’89,’h01,’h45}
end
A queue is an array, so if you really want to, you can still use array indexing to insert and
extract elements. As this example illustrates, you probably don’t really want to. The queue
methods are much more friendly.
We won’t bother examining this slide too closely.

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Quiz
Match the array that best meets each design need:
A. Packed array
B. Unpacked array
C. Dynamic array
D. Associative array
E. Queue
1. I want to concisely code an RTL instruction
processor to strip the opcode, address and
data fields off the instruction word…
2. I need to validate the architecture of my
processor stack…
3. I need to validate the architecture of my
packet data temporary storage…
4. I need to validate the architecture of my
instruction cache…
5. I want to perform matrix operations on fixed-
size “chunks” of data of the real type…
Solutions in Appendix A

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July 31, 2007
User-Defined Data Types and Structures
Chapter 5

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Primitive and User-Defined Types
Primitive data types
Built-in types not constructed from other data types
e.g. bit , logic , int , real
User-defined data types
Types named with typedef
Types constructed from other types
e.g. vectors and arrays
C-like enum for user-defined values sets
C-like struct to bundle multiple variables into one object
C-like union to store different data types in the same space
Support:
union
?
A primitive data-type is a built-in type that is not constructed from other types. Any other data
type is user-defined. This includes types that you named with the typedef keyword and types
you construct from other types, such arrays, enumerations, structures and unions.

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Type Definition
You can declare and name a type
using typedef
Verilog standard types
SystemVerilog user-defined types
You can use your type name
anywhere you can use a type
e.g. variable or port declaration