mov $fp, $sp

WHY WOULD YOU DO THIS?

Hi all,
            I am Ravi Kumar.N. My query is as follows:

     I have heard that two types of pointers are used to operate on a
stack  1) Stack Pointer  2) Frame Pointer.

   A) Please let me know what is the difference between these two
pointers.

  B) When "SP" comes into picture and when "FP" comes into picture.


  With Regards,
       Ravi Kumar.N