Which of the following statements (shown immediately below) is/are true about the arithmetic logic unit (ALU) ?The ALU performs arithmetic operations. The ALU performs logical operations. The ALU sometimes uses data stored in the registers to perform binary mathematics. The ALU sometimes stores the results of its calculations in the registers.单项选择题
A
a. Only statements 1, 2 and 4 are true.
B
b. None of the statements is true.
C
c. Only statements 1, 3 and 4 are true.
D
d. Statements 1, 2, 3 and 4 are true.

Question

Which of the following statements (shown immediately below) is/are true about the arithmetic logic unit (ALU) ?The ALU performs arithmetic operations. The ALU performs logical operations. The ALU sometimes uses data stored in the registers to perform binary mathematics. The ALU sometimes stores the results of its calculations in the registers.单项选择题

A

a. Only statements 1, 2 and 4 are true.

B

b. None of the statements is true.

C

c. Only statements 1, 3 and 4 are true.

D

d. Statements 1, 2, 3 and 4 are true.

BlackTom AI · Accepted Answer

First, let's restate what the question is asking: assess which statements about the arithmetic logic unit (ALU) are true.
Option a claims: Only statements 1, 2 and 4 are true. To evaluate this, we check each statement individually and see if any mismatch exists. If statement 3 is true, then option a would be incorrect.
Option b claims: None of the statements is true. This would require every statement to be false, which is unlikely given the fundamental role of the ALU in performing arithmetic, logic, and interacting with registers.
Option c claims: Only statements 1, 3 and 4 are true. This asserts that statement 2 is false. Since the ALU also performs logical operations, this would be incorrect unless you can argue logic operations are outside the ALU’s scope.
Option d claims: Statements 1, 2, 3 and 4 are true. This is a comprehensive claim that the ALU handles arithmetic, handles logical operations, uses data from registers for binary math, and stores results in registers.
Now, examine each statement:
- Statement 1: The ALU performs arithmetic operations. This is true by definition: adding, subtracting, multiplying, or otherwise manipulating binary numbers is a core ALU function.
- Statement 2: The ALU performs logical operations. Also true: the ALU carries out logical operations such as AND, OR, NOT, XOR as part of its capabilities.
- Statement 3: The ALU sometimes uses data stored in the registers to perform binary mathematics. This is true in typical processor designs: operands come from registers or memory, and the ALU uses register-held data for computations.
- Statement 4: The ALU sometimes stores the results of its calculations in the registers. This is true as well: the ALU outputs the result to a register (or to an accumulator) as part of the instruction execution cycle.
With all four statements aligning with standard processor architecture, option d is consistent with the typical description of ALU behavior. Consider why the other options fail:
- If you picked option a (only 1, 2 and 4 true), you would be denying statement 3. However, operands commonly reside in registers and are used by the ALU for computations, so statement 3 is correct, making option a inconsistent.
- If you picked option b (none true), you would be denying the essential arithmetic and logic capabilities of the ALU and its interaction with registers, which contradicts fundamental CPU design.
- If you picked option c (only 1, 3 and 4 true), you would be denying statement 2, which asserts the ALU performs logical operations; since logical operations are a standard ALU function, this option would be incorrect.
In summary, the combination of statements 1 through 4 accurately describes the ALU’s typical roles in arithmetic, logic, operands from registers, and writing results back to registers, making option d a complete and correct characterization.