Quick Protected Object question

[markp <markwork66@yahoo.com>]

I have a very quick protected object question. In a standard proected
object setup as follows:

protected Test is
   procedure A;
   procedure B;
private
   Z : integer := 0;
end Test;

protected body Test is
   procedure A is
   begin
      < set of statements>
   end A;

   procedure B is
   begin
      < set of statements>
   end B;
end Test;

The question is this: when procedure A is called, are all threads that
try to call B suspended until A finishes or, do the threads that call
B execute as long as A is not touching the private data "Z". Is the
lock at the procedure level or only at the data level?

Thank you.