set r1 as n/2;push the value of r1 into stack;reserve a palce in the stack for returned value;
n is even?
yes
no
start
expo
set r1 as (n-1);push the value of r1 into stack;reserve a palce in the stack for returned value;
(n=1)?
end
set r0 as 1;store the returned valued on stack;
reutrn
load the result from stack;remove the parameter from the stack;load the address of result into r0;store final result in result variable;
copy the value of fp to sp;load all regesters and return to the caller;
get input of x and n
