Lesson 2 - More on the FDE cycle

Question 1

What are all of the stages of the fde cycle?

Answer 1

• Program Counter copied to Memory Address Register
• Program Counter is incremented
• Address in Memory Address Register accessed in RAM via the address bus
• Data at that address in RAM is copied to the Memory Data Register via the data bus
• Memory Data Register is copied to the Current Instruction Register
• Contents of Current Instruction Register are decoded by the decode unit
• Instruction is split into opcode and operand
• Decoded instruction is executed

Question 2

What are the impacts are increasing the clock speed?

Answer 2

• Requires more energy
• Requires better cooling
• Means more processess can happen at the same time.

Question 3

What are the benefits of having more cores?

Answer 3

• It can have independently running FDE cycles at the same time

Question 4

What is pipeling?

Answer 4

Doing all of the instructions after each other.

Question 5

What is flushing the pipe?

Answer 5

Clearing what is in the CPU registers are sestarting the CPU fde cycle.

Question 6

List four points about the Havard memory architechture

Answer 6

• The instruction sizes can be larger
• It is more expensive than other computer architechtures.
• Is quicker
• Instructions can be fetched in parallel.

Question 7

List two points about Contemporary architechiture.

Answer 7

• Only has one memory cell

- The cahce is split up on the CPU.

Question 8

What would the steps be of LOAD instruction

Answer 8

• The instruction is decoded into the opcode and oprand sections.
• The address is copied into the MAR.
• The value at the address in the MAR is then copied to the MDR.
• The value in the MDR is copied to the ACC.

Question 9

What would the steps be of a STORE instruction

Answer 9

• The instruction is decoded into the opcode and oprand sections.
• The address is copied into the MAR.
• The ACC is copied into the MDR.
• The MDR contents are copied to the location specified by the MAR.