Technical Questions

stack is portion of RAM used for saving the content of Program Counter and general purpose registers.

LIFO stacks, also known as "push down" stacks, are the conceptually simplest way of saving information in a temporary storage location for such common computer operations as mathematical expression evaluation and recursive subroutine calling.

ROM cannot be used as stack because it is not possible to write to ROM.

For D latch: always@(enable) q<=d;

For D flip flop: always@(opsedge clock) q<=d; 

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.

Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address od the top of the stack.

Sign flag, Zero flag, Auxillary flag, Parity flag, Carry flag.

Stack pointer and Program counter all have 16 bits.

the powerful cell phones can transmit a signal of 3 watts.