CISC & RISC

• What are the two main categories of instruction sets in computers?

  Complex Instruction Set Computer (CISC) and Reduced Instruction Set Computer (RISC)
• What is an instruction set in the context of a CPU?

  It is the set of all instructions written in machine code that can be recognized and executed by a CPU.
• What is the purpose of the execution unit in a computer?

  • Carries out all calculations
  • Operates on data loaded into registers
• What is the main goal of CISC architecture?

  • Complete tasks in as few lines of assembly as possible
  • Understand and execute a series of operations
• How does the execution time of a CISC instruction compare to a RISC instruction?

  A CISC instruction may take more than one machine or clock cycle to execute.
• What are the main characteristics of RISC architecture?

  • Uses simple instructions executed in a single clock cycle
  • Requires more lines of assembly code for tasks
  • Fewer transistors and less complex hardware
  • Supports pipelining for performance
• Why might RISC architecture seem less efficient at first glance?

  It requires more lines of code in assembly compared to CISC.
• In what types of devices has RISC architecture become popular?

  Low power and portable devices like smartphones and tablets.
• What are the advantages and disadvantages of RISC architecture compared to CISC?

  Advantages:

  • Simpler instructions
  • Lower energy requirements
  • Better for pipelining

  
  

  Disadvantages:

  • Fewer instructions available
  • Initially lacked software support
• What has contributed to the rise of RISC architecture in recent years?

  The reduction in price of RAM and increased sophistication of compiler technology.
• What is pipelining in the context of CPU architecture?

  • A technique to increase instruction throughput
  • Allows multiple instruction phases to overlap
• How does microcode benefit modern CISC processors?

  It allows CISC processors to operate in a RISC-like fashion.
• How did compiler technology influence the acceptance of RISC architecture?

  Increased sophistication of compilers made RISC more viable.
• Can you name a few devices that utilize RISC architecture?

  Smart TVs, smartphones, tablets, and home assistants.
• What does RISC stand for?

  Reduced Instruction Set Computers
• What is a characteristic of RISC processors?

  They include a small instruction set.
• How many lines of machine code does one instruction in RISC equal?

  One instruction equals one line of machine code.
• How long does it take to execute one instruction in RISC processors?

  It takes one clock cycle.
• What does CISC stand for?

  Complex Instruction Set Computers
• What is a characteristic of CISC processors?

  They include a large instruction set.
• What is the aim of CISC processors regarding assembly code?

  The aim is to complete tasks in as few lines of assembly code as possible.
• How are instructions in CISC processors built?

  Instructions are built into hardware.
• How many clock cycles does it take to complete a complex instruction in CISC?

  It takes more than one clock cycle.
• What is a feature of CISC processors regarding general-purpose registers?

  CISC processors have more general-purpose registers.
• What are the main differences between RISC and CISC processors?

  • RISC: Small instruction set, 1 instruction = 1 line of code, 1 clock cycle per instruction.
  • CISC: Large instruction set, aim for fewer lines of code, complex instructions take multiple clock cycles, more general-purpose registers.
• What does RISC stand for in computer architecture?

  Reduced Instruction Set Computer
• What is a key characteristic of RISC architecture regarding the compiler's work?

  The compiler does more work to translate high-level code to machine code
• What is a disadvantage of RISC architecture related to memory?

  It requires more RAM to store code
• Why is RISC architecture suitable for pipelining?

  Because it has a simpler instruction set that allows for efficient execution
• What is an advantage of RISC architecture regarding power consumption?

  It requires less power
• How does RISC architecture compare in manufacturing costs?

  It costs less to manufacture
• What does CISC stand for in computer architecture?

  Complex Instruction Set Computer
• What is a key characteristic of CISC architecture regarding the compiler's work?

  The compiler does less work to translate high-level code into machine code
• What is an advantage of CISC architecture related to memory usage?

  It needs less RAM since the code is shorter
• What is a characteristic of CISC architecture regarding specialized instructions?

  Many specialized instructions are made, despite only a few being used
• What is a disadvantage of CISC architecture related to power consumption?

  It requires more power
• How does CISC architecture compare in manufacturing costs?

  It costs more to manufacture
• What are the main differences between RISC and CISC architectures?

  • RISC:
  • Compiler does more work
  • Requires more RAM
  • Suitable for pipelining
  • Requires less power
  • Costs less to manufacture
  • CISC:
  • Compiler does less work
  • Requires less RAM
  • Many specialized instructions
  • Requires more power
  • Costs more to manufacture