ALU 101 Study Guide 2026
Everything you need to pass the ALU 101 exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 ALU 101 Exam Format at a Glance
📚 ALU 101 Topics to Study (34)
✍️ Sample ALU 101 Questions & Answers
1. What does an arithmetic shift right operation do to a signed binary number?
An arithmetic shift right shifts bits right and replicates the sign bit into the vacated positions, effectively dividing the signed value by 2.
2. What does it mean when the ALU's Carry Out and Overflow flags are set simultaneously after an addition?
CF set means unsigned overflow occurred; OF set means signed overflow occurred; both set means the result is invalid under both unsigned and signed interpretations.
3. Which type of instruction tells the ALU to compare two values?
A COMPARE (CMP) instruction subtracts two operands and sets the ALU flags without storing the result, allowing conditional decisions.
4. Which number system uses base 16 and is commonly used to represent ALU register values?
Hexadecimal (base 16) compactly represents 4-bit groups, making it natural for expressing byte and word values in registers.
5. What is the role of a Wallace tree in fast multiplier circuits within an ALU?
A Wallace tree uses a network of carry-save adders to reduce n partial products into a sum and carry row, which a final adder then combines quickly.
6. What addressing mode uses the value in a register as the memory address to access?
Register indirect addressing uses the value stored in a register as the effective memory address from which to load or store data.