Can someone please explain me how they got the CF and OF for question 2 and how did they figure out it was invalid in question 3? Please explain clearly and concisely.

For the following, assume AL and BL are registers that are 4 bits in length.

AL = 5h BL = Bh

1. What are the decimal values of unsigned AL and BL, and signed AL and BL? [4 points]

Unsigned: AL = 5 BL = 11

Signed: AL = 5 BL = 5

2. What are the hexadecimal value of AL, and the values of flags CF and OF after the SUB instruction (SUB AL, BL). [3 points]

AL = Ah C = 1 O = 1

3. If valid, what are the decimal values of unsigned AL and signed AL after the above instruction (SUB AL, BL)? [2 points]

(SUB AL, BL)? [2 points]

Invalid