ALU 101 Instruction Set and Operations 2

Question 1

What does the NOP instruction do in an ALU-based processor?

Accepted Answer

Performs no operation and advances the program counter

Answer

NOP (No Operation) causes the processor to do nothing and simply advance to the next instruction, used for timing, alignment, or placeholder purposes.

Question 2

The INC instruction in an ALU increments a value by:

Accepted Answer

1

Answer

The INC instruction adds 1 to its operand, incrementing the value by exactly one.

Question 3

Which operation clears (sets to 0) a specific bit in a register using the ALU?

Accepted Answer

AND with a mask of 0s in target positions

Answer

AND-ing with a mask that has 0s in the target bit positions clears those bits, as AND with 0 always produces 0.

Question 4

A rotate-right-through-carry operation moves bits to the right and:

Accepted Answer

Moves the LSB into the carry flag and the carry flag into the MSB

Answer

Rotate right through carry shifts bits right, placing the outgoing LSB into the carry flag and the previous carry flag value into the MSB.

Question 5

What is the result of XOR-ing a register value with itself (A XOR A)?

Accepted Answer

All 0s (zero)

Answer

XOR-ing any value with itself produces all zeros, because each bit XOR'd with itself yields 0.

ALU 101 - Arithmetic Logic Unit 101 Exam Practice Test

ALU 101 - Arithmetic Logic Unit 101 Exam Practice Test

ALU 101 Instruction Set and Operations 2