Computer Architecture Basics
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What role does instruction alignment play in a superscalar architecture?

  • It ensures instructions retrieve data from memory efficiently.
  • It allows multiple instructions to be fetched simultaneously. (correct)
  • It is critical for preventing memory leaks during instruction execution.
  • It prevents control hazards by avoiding branches.

    • Which component is essential for handling misaligned instructions in a two-way superscalar processor?

  • Instruction Register
  • Alignment Hardware (correct)
  • Branch Predictor
  • Memory Data Register

    • In the context of superscalar architectures, what challenge does branch instructions pose?

  • They slow down the data transfer between registers.
  • They increase the time needed for instruction execution.
  • They require more cache memory to store additional data.
  • They introduce control hazards that affect fetch logic. (correct)

    • What is the main function of the Instruction Fetch (IF) stage in a CPU pipeline?

    <p>To retrieve instructions from memory for processing.</p> Signup and view all the answers

    Which of the following registers is specifically used for storing the address of the instruction to be fetched next?

    <p>Program Counter</p> Signup and view all the answers

    Which type of hazard occurs due to dependencies between instructions in a pipeline?

    <p>Data Hazards</p> Signup and view all the answers

    Which of the following is NOT a type of memory addressing mode?

    <p>Floating</p> Signup and view all the answers

    What is one key advantage of using pipelining in CPU instruction execution?

    <p>It allows multiple instructions to be processed simultaneously.</p> Signup and view all the answers

    Which component of the microarchitecture is primarily responsible for executing arithmetic and logic operations?

    <p>ALU</p> Signup and view all the answers

    What effect does the number of registers have on the efficiency of an Instruction Set Architecture (ISA)?

    <p>Limited registers can impede the efficiency of instruction execution.</p> Signup and view all the answers

    What is the purpose of microcode in microarchitecture?

    <p>To translate complex instructions into simpler micro-operations.</p> Signup and view all the answers

    What is the primary function of Instruction Set Architecture (ISA)?

    <p>To define the set of instructions a computer can execute</p> Signup and view all the answers

    Which of the following is an example of a pipeline stage?

    <p>Decode</p> Signup and view all the answers

    Which model allows simultaneous access to instructions and data?

    <p>Harvard Model</p> Signup and view all the answers

    What is a potential consequence of control hazards in a pipeline?

    <p>The pipeline may fetch incorrect instructions due to branching.</p> Signup and view all the answers

    Which characteristic best describes RISC architecture?

    <p>A focus on a small set of efficient operations</p> Signup and view all the answers

    What is a key disadvantage of the Von Neumann model?

    <p>It is slower due to the single data path for instructions and data</p> Signup and view all the answers

    Which of the following describes a primary function of microcode?

    <p>To translate complex machine instructions into simpler microinstructions</p> Signup and view all the answers

    What differentiates CISC from RISC architectures?

    <p>CISC includes a larger set of complex instructions</p> Signup and view all the answers

    In the Modified Harvard Model, what feature is prominent?

    <p>Combination of separate and shared memory elements</p> Signup and view all the answers

    What type of instruction would fall under data movement instructions?

    <p>Transferring data between registers</p> Signup and view all the answers

    What is a cache hit?

    <p>When requested data is found in the cache</p> Signup and view all the answers

    Which metric directly affects the performance of a cache?

    <p>Block Size</p> Signup and view all the answers

    What constitutes a structural hazard in a pipeline?

    <p>Multiple instructions requiring the same hardware resources simultaneously.</p> Signup and view all the answers

    Which type of data hazard involves an instruction that must wait for a previous instruction's result before proceeding?

    <p>Read After Write (RAW)</p> Signup and view all the answers

    What is the average memory access time (AMAT) formula?

    <p>AMAT = Hit Time + (Miss Rate × Miss Penalty)</p> Signup and view all the answers

    What solution involves sending the results of a previous instruction directly to the next instruction without waiting for completion?

    <p>Data Forwarding/Bypassing</p> Signup and view all the answers

    Which factor generally reduces miss rates in a cache?

    <p>Increasing Cache Size</p> Signup and view all the answers

    What does superscalar architecture allow in a processor?

    <p>Multiple instruction processing per clock cycle</p> Signup and view all the answers

    What is a primary purpose of cache memory?

    <p>To reduce the average access time to frequently used data.</p> Signup and view all the answers

    Which type of cache is located closest to the CPU and is extremely fast but small in size?

    <p>L1 Cache</p> Signup and view all the answers

    What is a challenge associated with a two-way superscalar architecture?

    <p>Frequent pipeline stalls from resource contention</p> Signup and view all the answers

    What is a characteristic of a fully associative cache?

    <p>Any memory block can be stored in any cache location.</p> Signup and view all the answers

    Which of the following describes in-order execution?

    <p>Instructions are issued and executed in the order they appear</p> Signup and view all the answers

    Which technique involves anticipating what data will be needed soon?

    <p>Prefetching</p> Signup and view all the answers

    Which cache is designed to store both instructions and data?

    <p>Unified Cache</p> Signup and view all the answers

    What technique automatically inserts stalls to prevent data hazards?

    <p>Pipeline Interlocks</p> Signup and view all the answers

    What role does microcode play in a CPU's operation?

    <p>It guides CPU components through instruction execution.</p> Signup and view all the answers

    What is a significant disadvantage of using microinstructions in CISC architectures?

    <p>They can introduce additional latency.</p> Signup and view all the answers

    What does pipeline depth refer to in CPU architecture?

    <p>The number of stages in the instruction pipeline.</p> Signup and view all the answers

    Which of the following best describes a benefit of pipelining in CPU architectures?

    <p>Increases instruction throughput over time.</p> Signup and view all the answers

    What is a challenge associated with pipelining in CPU design?

    <p>It can cause stalls if hazards occur.</p> Signup and view all the answers

    Which stage of the pipeline is primarily responsible for retrieving the next instruction?

    <p>Instruction Fetch (IF)</p> Signup and view all the answers

    How does pipelining contribute to efficient resource usage in CPUs?

    <p>By utilizing each pipeline stage simultaneously.</p> Signup and view all the answers

    What is one reason why RISC architectures may perform better compared to CISC architectures?

    <p>They have fewer layers of execution.</p> Signup and view all the answers

    Study Notes

    Instruction Set Architecture (ISA)

    • Defines the set of instructions a computer can execute.
    • Acts as an interface between hardware and software.
    • Determines instruction formats, addressing modes, registers, and data types.

    Microcode

    • A lower-level set of instructions used by complex CPUs to implement higher-level instructions.
    • Translates complex machine instructions into simpler, sequenced microinstructions.
    • Stored in special, faster storage within the CPU (e.g., ROM or RAM).

    Machine Models

    • Von Neumann Model
      • Instructions and data share the same memory and data bus.
      • Known for the Von Neumann Bottleneck (delays).
      • Simple and easy for general purpose computing.
    • Harvard Model
      • Separate memory and buses for instructions and data.
      • Allows simultaneous access, increasing performance and reducing bottlenecks.
      • Often used in digital signal processing and microcontrollers.
    • Modified Harvard Model
      • Combines features of Von Neumann and Harvard.
      • Allows transfer between instruction and data memories.
      • Adds flexibility and is common in modern CPUs.

    ISA Characteristics

    • Complexity:

      • RISC (Reduced Instruction Set Computer): Simple and minimal instructions.
      • CISC (Complex Instruction Set Computer): Larger set of complex instructions.

    • Instruction Types and Formats:

      • Include arithmetic, logical, control, and data movement instructions.
      • Varying sizes and formats based on operation types.

    • Registers:

      • Defines types and numbers of registers (general-purpose, floating-point).
      • Limited numbers, affecting ISA efficiency.

    • Memory Addressing Modes:

      • Various methods, including immediate, direct, indirect, indexed, and base-plus-offset.
      • Affects program's ability to access data.

    • Data Types: Defines supported data types (integers, floating-point, characters, etc.).

    Pipeline

    • Basic Concept:

      • Divides instruction execution into stages (fetch, decode, execute, memory access, write-back).
      • Allows simultaneous processing, improving throughput.

    • Pipeline Stages:

      • Fetch: Retrieves the instruction.
      • Decode: Decodes the instruction.
      • Execute: Performs the operation.
      • Memory Access: Accesses memory.
      • Write-back: Stores the result.

    • Pipeline Hazards:

      • Data Hazards: Instructions depend on previous results.
      • Control Hazards: Pipeline encounters branch instructions.
      • Structural Hazards: Insufficient resources for parallel execution.

    • Advantages of Pipelining:

      • Higher throughput (more instructions in shorter time)
      • Efficient CPU resource utilization (reduces idle time)
      • Improved performance (Higher IPC)

    Microcoded Microarchitecture

    • Refers to the internal CPU architecture implementing ISA instructions.

    • Consists of functional blocks like ALU, control unit, registers, and cache.

    • Microcode translates complex instructions into simpler micro-operations.

      • Controls each CPU function in sequence.
      • Enables complex instruction execution, especially in CISC architectures.

    • Microprogram Control Unit: Stores and manages microinstructions in high-speed memory.

    Cache

    • Purpose: Small, high-speed memory near the CPU, storing frequently accessed data and instructions.

    • Reduces average access time from main memory.

    • Types:

      • Instruction Cache (I-Cache): Stores instructions.
      • Data Cache (D-Cache): Stores data.
      • Unified Cache: Stores both.

    • Levels:

      • L1 Cache: Closest to CPU, fast but small.
      • L2 Cache: Larger, slightly slower.
      • L3 Cache: Larger, shared among cores, slower.

    • Mapping Techniques:

      • Direct-Mapped: Each memory block maps to exactly one cache location.
      • Fully Associative: Any memory block can be stored in any cache location.
      • Set-Associative: Compromise between the two.

    • Performance Metrics:

      • Hit Rate: Percentage of accesses where data is in the cache.
      • Miss Rate: Percentage of accesses where data is not in the cache.
      • Miss Penalty: Extra time to retrieve data from main memory.
      • AMAT (Average Memory Access Time): Hit Time + (Miss Rate x Miss Penalty).

    Control Hazards

    • Occur when pipeline encounters instructions altering program counter (PC) like jumps/branches.

    • Can cause pipeline stalls, reducing efficiency.

    • Types of Control Hazards:

      • Jump Instructions (unconditional, PC set to a new address).
      • Branch Instructions (conditional, altering PC based on conditions)
      • Potential Pipeline Impacts: If branch is taken, instructions after branch must be discarded.

    • Solutions:

      • Branch Prediction for quicker branch decisions (static/dynamic).

    Superscalar Architecture

    • A processor design that issues and executes multiple instructions per clock cycle.

    • Increase instruction-level parallelism.

    • Requires multiple execution units for simultaneous instruction processing.

    • In-Order Execution: Issues and executes instructions in program order, can have pipeline stalls if dependent instructions need same resources.

    • Challenges : Requires careful handling of instruction dependencies , can cause pipelines stalls.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Unit IV: Instruction Set Architecture PDF

    Description

    This quiz covers fundamental concepts of computer architecture, including Instruction Set Architecture (ISA), microcode, and different machine models such as Von Neumann and Harvard. Test your understanding of these key principles that bridge hardware and software in computing systems.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser