Lectures 10 - 15

Question 1

What digits does the Octal number system use?

Answer 1

0 through 7

Question 2

What are numbers starting with 0 treated as in many languages?

Answer 2

An octal number - so 01 is not equal to the decimal 1

Question 3

What does 0 + 1 equal in binary addition?

Answer 3

1

Question 4

What does 1 + 1 equal in binary addition?

Answer 4

0, but a 1 is carried to the next column

Question 5

What does 1 - 1 equal in binary substitution?

Answer 5

0

Question 6

What does 0 - 1 equal in binary substitution?

Answer 6

Take a 1 from the next column

Question 7

How do we add in Hexadecimal?

Answer 7

Convert both items to decimal, then add, then convert back to Hex.

Question 8

How do we substitute in Hexadecimal?

Answer 8

If a larger number is taken away from a smaller number, then 10 is taken from the next column. i.e:
3-E won’t work; take 10 from next column to make it
13-E

Question 9

What is RISC?

Answer 9

Reduced Instruction Set Computing

Question 10

What is CISC?

Answer 10

Complex Instruction Set Computing

Question 11

What are the characteristics of RISC?

Answer 11

• Small, very optimised instruction set
• Separates load & storing function
• Fixed size instructions
• Single or few cycle execution
• Conditional execution
• Easier for compilers

Question 12

What are the characteristics of CISC?

Answer 12

• Large & versatile set
• Many addressing modes with complex functions
• May have high level operations
• High density
• Easier for humans

Question 13

How do CPU’s get and run instructions?

Answer 13

The fetch-execute cycle

Question 14

What are the steps in the Fetch execute cycle?

Answer 14

1: Copy PC to MAR
2: Increment PC
3: Get data from memory, copy to MBR
4: Copy MBR to IR
5: Copy opcode (in IR) to control unit
6: (Example instruction) Store accumulator to memory
7: Copy address in IR.addr to MAR
8: Copy ACC to MAR
9: Write the data to memory