Consider the following LEGv8 loop:

LOOP: SUBIS X1, X1, #0

B.LE DONE

SUBI X1, X1, #1

ADDI X0, X0, #2

B LOOP

DONE:

a. For the loop wirtten in LEGv8 assembly above, replace teh instruction B.LE DONE with B.MI DONE. What is the final value in register X0 assuming X0 is initially zero?

b. Show how you can reduce the number of instructions by combining the SUBIS and SUBI instructions. (Hint: Add one instruction outside the loop)