This set of Computer Organization and Architecture Multiple Choice Questions & Answers (MCQs) focuses on “Addressing Modes”.
1. The instruction, Add #45,R1 does _______
a) Adds the value of 45 to the address of R1 and stores 45 in that address
b) Adds 45 to the value of R1 and stores it in R1
c) Finds the memory location 45 and adds that content to that of R1
d) None of the mentioned
Explanation: The instruction is using immediate addressing mode hence the value is stored in the location 45 is added.
2. In the case of, Zero-address instruction method the operands are stored in _____
c) Push down stack
Explanation: In this case, the operands are implicitly loaded onto the ALU.
3. Add #45, when this instruction is executed the following happen/s _______
a) The processor raises an error and requests for one more operand
b) The value stored in memory location 45 is retrieved and one more operand is requested
c) The value 45 gets added to the value on the stack and is pushed onto the stack
d) None of the mentioned
4. The addressing mode which makes use of in-direction pointers is ______
a) Indirect addressing mode
b) Index addressing mode
c) Relative addressing mode
d) Offset addressing mode
Explanation: In this addressing mode, the value of the register serves as another memory location and hence we use pointers to get the data.
5. In the following indexed addressing mode instruction, MOV 5(R1),LOC the effective address is ______
a) EA = 5+R1
b) EA = R1
c) EA = [R1].
d) EA = 5+[R1].
Explanation: This instruction is in Base with offset addressing mode.
6. The addressing mode/s, which uses the PC instead of a general purpose register is ______
a) Indexed with offset
d) both Indexed with offset and direct
Explanation: In this, the contents of the PC are directly incremented.
7. When we use auto increment or auto decrements, which of the following is/are true?
1) In both, the address is used to retrieve the operand and then the address gets altered
2) In auto increment, the operand is retrieved first and then the address altered
3) Both of them can be used on general purpose registers as well as memory locations
a) 1, 2, 3
c) 1, 3
d) 2, 3
Explanation: In the case of, auto increment the increment is done afterward and in auto decrement the decrement is done first.
8. The addressing mode, where you directly specify the operand value is _______
9. The effective address of the following instruction is MUL 5(R1,R2).
Explanation: The addressing mode used is base with offset and index.
10. _____ addressing mode is most suitable to change the normal sequence of execution of instructions.
c) Index with Offset
Explanation: The relative addressing mode is used for this since it directly updates the PC.
Sanfoundry Global Education & Learning Series – Computer Organization and Architecture.