1. What is out-of-order execution in CPU architecture?
(A) Executing instructions in the order they appear in the program
(B) Executing instructions in an order different from the program order
(C) Executing only the most recent instructions
(D) Ignoring the instruction order entirely
2. The main advantage of out-of-order execution is:
(A) Increased instruction fetch rate
(B) Reduced memory access latency
(C) Improved CPU pipeline efficiency
(D) Enhanced power consumption
3. Which hardware component is primarily responsible for implementing out-of-order execution?
(A) Memory management unit
(B) Cache controller
(C) Arithmetic Logic Unit
(D) Instruction scheduler
4. What is the purpose of the instruction reordering in out-of-order execution?
(A) To reduce instruction latency
(B) To improve instruction cache performance
(C) To ensure sequential consistency
(D) To increase the clock speed
5. Which of the following is a common issue in out-of-order execution?
(A) Cache coherence
(B) Instruction fetch rate
(C) Branch prediction
(D) Instruction dependency
6. In out-of-order execution, what is the role of the instruction window?
(A) To cache instructions for future execution
(B) To hold instructions that are waiting to be executed
(C) To reorder instructions before execution
(D) To manage instruction fetch operations
7. Which of the following techniques helps resolve data hazards in out-of-order execution?
(A) Register renaming
(B) Branch prediction
(C) Cache replacement
(D) Memory interleaving
8. What is register renaming used for in out-of-order execution?
(A) To increase the number of registers available
(B) To eliminate false data dependencies
(C) To improve memory access speed
(D) To optimize cache usage
9. The primary challenge of implementing out-of-order execution is:
(A) Increased instruction fetch bandwidth
(B) Reduced register file size
(C) Complex instruction scheduling
(D) Simplified pipeline design
10. In out-of-order execution, what is a “scoreboard”?
(A) A mechanism for tracking instruction status and dependencies
(B) A cache used for instruction storage
(C) A unit that handles instruction decoding
(D) A method for branch prediction
11. Which of the following is NOT a benefit of out-of-order execution?
(A) Reduced instruction execution time
(B) Improved pipeline utilization
(C) Enhanced parallelism
(D) Increased power consumption
12. What type of dependency does out-of-order execution aim to resolve?
(A) Control dependency
(B) Timing dependency
(C) Data dependency
(D) Structural dependency
13. What is a “reorder buffer” in out-of-order execution?
(A) A cache that stores frequently used instructions
(B) A buffer that holds instructions until they can be committed in order
(C) A unit that renames registers
(D) A mechanism for branch prediction
14. Which of the following best describes the role of the instruction scheduler in out-of-order execution?
(A) To fetch instructions from memory
(B) To execute instructions sequentially
(C) To determine the order in which instructions are executed
(D) To decode instructions into machine code
15. What is a potential drawback of out-of-order execution?
(A) Reduced instruction throughput
(B) Increased complexity of CPU design
(C) Increased instruction fetch time
(D) Simplified instruction scheduling
16. In out-of-order execution, what is meant by “issue stage”?
(A) The stage where instructions are sent to the execution units
(B) The stage where instructions are decoded
(C) The stage where instructions are committed to the register file
(D) The stage where instructions are fetched from memory
17. Which technique helps reduce the impact of branch mispredictions in out-of-order execution?
(A) Branch prediction
(B) Register renaming
(C) Out-of-order issue
(D) Instruction reordering
18. What does the term “instruction window” refer to in out-of-order execution?
(A) The number of instructions that can be fetched per cycle
(B) The number of instructions held and managed for execution
(C) The range of memory addresses used for instruction fetching
(D) The time taken for an instruction to be executed
19. How does out-of-order execution affect cache utilization?
(A) It improves cache hit rates by predicting future instructions
(B) It reduces the need for large caches
(C) It can cause increased cache misses due to instruction reordering
(D) It eliminates the need for cache coherence
20. What is the “commit stage” in out-of-order execution?
(A) The stage where instructions are fetched
(B) The stage where instructions are decoded
(C) The stage where instructions are written back to the register file
(D) The stage where instructions are executed
21. In out-of-order execution, which of the following is used to manage instruction dependencies?
(A) Instruction buffer
(B) Dependency map
(C) Issue queue
(D) Reorder buffer
22. What is the primary role of the execution units in out-of-order processors?
(A) To decode instructions
(B) To schedule instructions
(C) To execute instructions as soon as they are ready
(D) To fetch instructions from memory
23. How does out-of-order execution affect instruction-level parallelism (ILP)?
(A) It reduces ILP
(B) It increases ILP by allowing instructions to execute as soon as dependencies are resolved
(C) It has no effect on ILP
(D) It decreases the number of instructions that can be executed
24. What is a “data hazard” in the context of out-of-order execution?
(A) When an instruction depends on data that has not yet been produced
(B) When multiple instructions are executed simultaneously
(C) When instructions are fetched out of sequence
(D) When instructions are reordered incorrectly
25. Which component helps in managing the state of instructions in out-of-order execution?
(A) Instruction fetch unit
(B) Instruction decoder
(C) Instruction scheduler
(D) Instruction status register
26. What is “speculative execution” in out-of-order processors?
(A) Executing instructions based on predicted paths before the actual path is known
(B) Reordering instructions after execution
(C) Waiting for all dependencies to be resolved before executing
(D) Running instructions in the exact program order
27. Which of the following is NOT typically used to resolve control hazards in out-of-order execution?
(A) Branch prediction
(B) Speculative execution
(C) Register renaming
(D) Instruction buffering
28. In out-of-order execution, what does “out-of-order issue” refer to?
(A) Issuing instructions in the program order
(B) Issuing instructions based on availability rather than order
(C) Issuing instructions only when all dependencies are resolved
(D) Issuing instructions only to the next execution unit
29. What role does the “issue queue” play in out-of-order execution?
(A) It holds instructions until they can be executed
(B) It stores the results of executed instructions
(C) It manages memory accesses
(D) It schedules the execution of instructions
30. Which of the following is a challenge associated with speculative execution?
(A) Increased instruction throughput
(B) Increased power consumption and complexity
(C) Reduced instruction latency
(D) Simplified control flow