Quiz 1 Solution-assembly

60266
Quiz 1 Solution

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]
Full Marks:
Invalid
Half marks:
Unsigned = 10d
Signed = ‐6d

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60266

Quiz 1 Solution

_______For the following, assume AL and BL are registers that are 4 bits in length.
AL = Bh
BL = 4h
1. What are the decimal values of unsigned AL and BL, and signed AL and BL. [4 points]
Unsigned:
AL = 11d
BL = 4d
Signed:
AL = ‐5d
BL = 4d
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 = 7d
C = 0
O = 1
3. If valid, what are the decimal values of unsigned AL and signed AL after the SUB
instruction (SUB AL, BL)? [2 points]
Full Marks:
Invalid
Half Marks:
Unsigned: 7d
Signed: 7d

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60266

Quiz 1 Solution

For the following, assume AL and BL are registers that are 4 bits in length.
AL = Eh
BL = Ch
1. What are the decimal values of unsigned AL and BL, and signed AL and BL. [4 points]
Unsigned:
AL = 14d
BL = 12d
Signed:
AL = ‐2d
BL = ‐4d
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 = 2h
C = 0
O = 0
3. If valid, what are the decimal values of unsigned AL and signed AL after the SUB
instruction (SUB AL, BL)? [2 points]
Unsigned:
AL = 2d
Signed:
AL = 2d