I need help on my Computer Operation assignment.

Assume that registers X0 and X1 hold the values 0x8000000000000000 and 0xD000000000000000, respectively:

a) For the contents of registers X0 and X1 as specified above, what is the value of X9 for the following assembly code?

SUB X9, X0, X1

b) Is the result in X9 the desired result, or has there been overflown?

c) For the contents of registers X0 and X1 as specified above, what is the value of X9 for the following assembly code?

-ADD X9, X0, X1

-ADD X9, X9, X0

d) Is the result in X9 the desired result, or has there been overflown?