[1.1.2] | 2: CISC & RISC

Question 1

What is an instruction set?

Answer 1

• All the machine code instructions that a CPU can execute.

Question 2

Fill in the blank for CISC & RISC:
_______ Instruction Set Computer

Answer 2

• Complex
• Reduced

Question 3

Compare the design philosophies of CISC & RISC

Answer 3

• CISC: Complex & powerful instructions at the cost of slower, larger processors.

• RISC: Focuses on simplicity and speed, using a limited set of instructions.

Question 4

How does software using CISC compare to RISC software?

Answer 4

• CISC: Software is simpler at the expense of more complex hardware

• RISC: Software is more complex as a result of simpler hardware.
• 1 high-level instruction may equal 4 low-level ones for example.

Question 5

How does the execution of CISC and RISC instructions compare?

Answer 5

• CISC: Instructions may take multiple clock cycles, aiming to reduce the total number of instructions.

• RISC: Most instructions take a single clock cycle, focusing on speed.

Question 6

What are the advantages (2) & disadvantages (3) of CISC?

Answer 6

Advantages:

• Easier compiling
• Shorter low-level programs

Disadvantages:

• Required more hardware
• More expensive
• Less power-efficient

Question 7

What are the advantages (2) of RISC?

Answer 7

• Simpler hardware
• More efficient pipelining