Which of the following statements is/are FALSE? (i) In floating-point…
2019
Which of the following statements is/are FALSE? (i) In floating-point arithmetic, addition and subtraction operations are more complex than multiplication and division operations. (ii) A floating-point arithmetic can never produce exponent overflow or exponent underflow.
- A.
Neither (i) nor (ii) is false
- B.
Both (i) and (ii) are false
- C.
Only (i) is false
- D.
Only (ii) is false
Attempted by 9 students.
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Correct answer: D
Answer: Only statement (ii) is false — the claim that floating-point arithmetic can never produce exponent overflow or underflow is incorrect.
Why the claim that addition and subtraction are more complex is true:
Exponent alignment: before adding or subtracting, the operand with the smaller exponent must have its mantissa shifted to align exponents, which is an extra step not needed for multiplication.
Rounding and sticky bits: shifting may require tracking guard/round/sticky bits to round the result correctly, adding complexity.
Normalization: after the operation the result may need normalization (adjusting mantissa and exponent) and possible re-rounding.
By contrast, multiplication/division operate on mantissas and add/subtract exponents; they still may need normalization, but they do not require exponent alignment prior to the core mantissa operation.
Why the claim that exponent overflow/underflow can never occur is false:
Overflow: occurs when a result's exponent exceeds the maximum representable exponent; IEEE 754 typically produces Infinity or signals an overflow and sets related status flags.
Underflow: occurs when a result's magnitude is smaller than the smallest normalized value; implementations may produce subnormal (denormal) numbers or zero and raise an underflow flag.
Both overflow and underflow are real behaviors in floating-point arithmetic and are handled according to the floating-point standard or the implementation's choices.
Conclusion: addition and subtraction are indeed more complex in many implementations due to exponent alignment and related steps, and floating-point arithmetic can produce exponent overflow and underflow; therefore only the statement denying overflow/underflow is false.