Unit 17

Question 1

lw R₁, Kd(R₂)
What does the above do?

Answer 1

The value from word adress (Kd + R₂) is updated into register R₁
note: Kd = sx(⃗ b)
R1 := !W [!R2 + sx(⃗ b)]

Question 2

sw R₁, Kd(R₂)
What does the above do?

Answer 2

The value from register R₁ is updated into main memory of adress Kd + R₂
note: Kd = sx(⃗ b)
W [!R2 + sx(⃗ b)] := !R1

Question 3

How is each machine instruction stored?
How is Kd stored in the instruction?
What type of BInary is Kd?

Answer 3

Each machine isntruction is storteds as a 32 bit binary number
The denary number Kd is stored as the rightmost 16 bits
Kd is stored as sighned binary as it can be negative

Question 4

What are the three formats a 32 bit mahcine instruction can belong to?

Answer 4

R,I and J

Question 5

Give an example of an R-format example?

Answer 5

name R1, R2, R3 such as add $t0, $s1, $s2, and sub, and, . . .

Question 6

A R-format instruction is 32 bits long but it vcan be broken down into the following sections:
6bits
5bits
5bits
5bits
5bits
6bits
Name each of the sections and use registers R₁,R₂,R₃?

Answer 6

6bits : Opcode (op) always 6 zeros
5bits: rs (R₂)
5bits:rt (R₃)
5bits:rd (R₁)
5bits: shamt (don’t need to study)
6bits: funct (function) #specifies waht functiuon we want the ALU to perform

Question 7

Give an example of an I-format example?

Answer 7

name R1, R2, Kd (Kd= denary number)

Question 8

A I-format instruction is 32 bits long but it vcan be broken down into the following sections:
6bits
5bits
5bits
16bits
Name each of the sections and use registers R₁,R₂?

Answer 8

6bits : Opcode (op) #stores instructions for the ALU for example addi
5bits: rs (R₂)
5bits:rt (R₃)
16bits:address (⃗b)

Question 9

Answer 9