tasks
Table of Contents
Tasks and Functions provide a means of splitting code into small parts.
A Task can contain a declaration of parameters, input arguments, output arguments, in-out arguments, registers, events, and zero or more behavioral statements.
SystemVerilog task can be,
- static
- automatic
Static tasks
Static tasks share the same storage space for all task calls.
Automatic tasks
Automatic tasks allocate unique, stacked storage for each task call.
SystemVerilog allows,
- to declare an automatic variable in a static task
- to declare a static variable in an automatic task
- more capabilities for declaring task ports
- multiple statements within task without requiring a begin…end or fork…join block
- returning from the task before reaching the end of the task
- passing values by reference, value, names, and position
- default argument values
- the default direction of argument is input if no direction has been specified
- default arguments type is logic if no type has been specified
task examples
task arguments in parentheses
module sv_task;
int x;
//task to add two integer numbers.
task sum(input int a,b,output int c);
c = a+b;
endtask
initial begin
sum(10,5,x);
$display("\tValue of x = %0d",x);
end
endmodule
Simulator Output
Value of x=15
task arguments in declarations and mentioning directions
module sv_task;
int x;
//task to add two integer numbers.
task sum;
input int a,b;
output int c;
c = a+b;
endtask
initial begin
sum(10,5,x);
$display("\tValue of x = %0d",x);
end
endmodule
Simulator Output
Value of x = 15