Blocking Assignment
Blocking assignment statements execute in series order. Blocking assignment blocks the execution of the next statement until the completion of the current assignment execution.
Blocking assignment example
In Below Example, a and b is initialized with value 10 and 15 respectively, after that b is being assigned to a (a value will become 15), and value 20 is assigned to b. After assignment value of a = 15 and b=20.
module blocking_assignment;
//variables declaration
int a,b;
initial begin
$display("-----------------------------------------------------------------");
//initializing a and b
a = 10;
b = 15;
//displaying initial value of a and b
$display("\tBefore Assignment :: Value of a is %0d",a);
$display("\tBefore Assignment :: Value of b is %0d",b);
a = b;
b = 20;
$display("\tAfter Assignment :: Value of a is %0d",a);
$display("\tAfter Assignment :: Value of b is %0d",b);
$display("-----------------------------------------------------------------");
end
endmodule
Simulator Output:
----------------------------------------------------------------- Before Assignment :: Value of a is 10 Before Assignment :: Value of b is 15 After Assignment :: Value of a is 15 After Assignment :: Value of b is 20 -----------------------------------------------------------------
Blocking assignment example-2
In Below Example, a and b are initialized with value 10 and 15 respectively, after that b is being assigned to a (a value will become 15), and value 20 is assigned to b. After assignment value of a = 15 and b = 20.
module blocking_assignment;
//variables declaration
int a,b;
int x,y;
initial begin
//initializing a and b
a = 10;
b = 15;
x = a + b;
y = a + b + x;
$display("-----------------------------------------------------------------");
$display("\tValue of x is %0d",x);
$display("\tValue of y is %0d",y);
$display("-----------------------------------------------------------------");
end
endmodule
Simulator Output:
----------------------------------------------------------------- Value of x is 25 Value of y is 50 -----------------------------------------------------------------