Questions

Program counter holds the address of either the first byte of the next instruction to be fetched for execution of the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.

A blocking assignment is one in which the statements are executed sequentially, i.e., first statement is executed and variable is assigned  a value then second is executed and so on. A non blocking assignment is  one in which statements occurs conturrently, only non blocking assignments should be used in sequential circuit.

e.g.

initial

begin

a=b; //blocking

c<=a; //nonblocking

d=c; // blocking

end

In this example firstly the value of b is assigned to a and this value is assigned to c only after execution of first statement. the second and the third statements are executed simultaneously, i.e. value a ais assigned to c and previous value if c is assigned to d.