ALU stands for
2012
ALU stands for
Answer: D. Arithmetic Logic Unit — Concept: one functional block inside the CPU is dedicated to computing on operand values, and the work that block does is described by two named classes of…
- A.
American Logic Unit
- B.
Alternate Local Unit
- C.
Alternating Logic Unit
- D.
Arithmetic Logic Unit
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Correct answer: D
Concept: one functional block inside the CPU is dedicated to computing on operand values, and the work that block does is described by two named classes of operation. Arithmetic operations act on the numeric value of the operands — adding, subtracting, incrementing, comparing magnitudes. Logic operations act on the operands bit by bit — combining or inverting individual bits with no notion of numeric value. The abbreviation for that block is built from the name of each class plus the word for the block itself.
Application: ALU expands to Arithmetic Logic Unit, and the two halves of that name map exactly onto the two halves of the block's job.
Arithmetic side: addition, subtraction, increment and decrement, and magnitude comparison carried out on binary operands.
Logic side: bitwise AND, OR, NOT and XOR, together with shift and rotate in most designs.
By-product: status flags such as zero, carry, sign and overflow, which the control unit reads to decide conditional branches.
Cross-check: read each rival expansion by what its own leading qualifier denotes.
Expansion | What its leading qualifier denotes |
|---|---|
American Logic Unit | National origin — the sense the word carries in American National Standards Institute. |
Alternate Local Unit | A substitute role together with a scope — availability and reach, rather than any operation on data. |
Alternating Logic Unit | Periodic reversal — the sense the word carries in alternating current, an electrical property of a supply. |
Arithmetic Logic Unit | Numeric calculation, paired with bitwise logic — the two operation classes the block performs. |
Result: only the expansion Arithmetic Logic Unit names both operation classes the block actually carries out. In the classical CPU organisation — control unit + ALU + registers — the control unit sequences instructions, the registers hold the operands, and the ALU is the block that computes.