MIPs Instruction Set

Question 1

How can XOR be used in machine code?

Answer 1

To clear a register

XORing a number with itself results in zero.

Question 2

What happens when you XOR a number with itself?

Answer 2

The result is zero

This is a property of the XOR operation.

Question 3

What is the effect of XORing a number twice?

Answer 3

You get the original number back again

This property can be useful in encryption schemes.

Question 4

What is the result of zero-extending a 16-bit immediate value?

Answer 4

The upper 16 bits contain all zeroes

This is relevant when working with immediate values in logical operations.

Question 5

What is the syntax for the AND immediate operation in MIPS?

Answer 5

andi $rt, $rs, immed

This operation performs a bitwise AND with an immediate value.

Question 6

What is the syntax for the OR immediate operation in MIPS?

Answer 6

ori $rt, $rs, immed

This operation performs a bitwise OR with an immediate value.

Question 7

What is the syntax for the XOR immediate operation in MIPS?

Answer 7

xori $rt, $rs, immed

This operation performs a bitwise XOR with an immediate value.

Question 8

What ae the 3 types of MIPs instructions?

Answer 8

R-Type
I-Type
J-Type

Question 9

What does a R-Type instruction refer to?

Answer 9

Register type

Question 10

How many bits are in each & what does each mean?

Answer 10

op - 6 bits - Specifies the operation
rs - 5 bits - Address of the first operand
rt - 5 bits - Address of the second operand
rd - 5 bits - Address of the results destination
shamt - 5 bits - Shift amount
funct - 6 bits - Function code

R-Type instruction

Question 11

How many operations can the opcode carry out in R-Type, I-Type, J-Type?

Answer 11

64 operations

6 bits = 2^6 = 64 operations

Question 12

How many bits are in each & what does each mean?

Answer 12

op - 6 bits - opcode that specifies the operation
rs - 5 bits - register file address of the base address register
rt - 5 bits - register file address to receive result of the load
offset - 16 bits - Constant or address offset

I-Type instruction

Question 13

How many bits are in eacg & what does each mean?

Answer 13

op - 6 bits - opcode that specifies the jump operation
address - 26 bits - target address

SSconcatenated with upper four bits of PC
and 00 appended to end

Question 14

What does sll & srl mean?

Answer 14

Shift left & Shift right

Question 15

Why do we use sll & srl?

Answer 15

Used in multiplication & division

It’s much faster

Question 16

What is the output to a OR gate?

Answer 16

Must be atleast 1

Question 17

What is the output to a NOR gate?

Answer 17

Must be no 1s (Opposite of OR)

Question 18

What type of gate is this?

Answer 18

AND Gate

Question 19

What bitwise operation is this?

______ $t0,$t1,$t2

Answer 19

OR

Question 20

What bitwise operation is this?

______ $t0,$t1,$t2

Answer 20

NOR

Question 21

What bitwise operation is this?

______ $t0,$t1,$t2

Answer 21

XOR

Question 22

What type of gate is this?

Answer 22

OR Gate

Question 23

What type of gate is this?

Answer 23

NOR Gate

Question 24

What type of gate is this?

Answer 24

XOR Gate

Question 25

What is the output to a XOR gate?

Answer 25

## Footnote Must only be a single 1

Question 26

What is the output to a AND gate?

Answer 26

## Footnote Must be all 1s

Question 27

What bitwise operation is this? ## Footnote ______ $t0,$t1,$t2

Answer 27

AND

Question 28

What does: bne $s0, $s1, Lbl mean?

Answer 28

Go to Lbl if $s0 != $s1 | Lbl: will be the start of the line to go to ## Footnote Branch if not equal

Question 29

What does: beq $s0, $s1, Lbl mean?

Answer 29

Go to Lbl if $s0 = $s1 | Lbl: will be the start of the line to go to ## Footnote Branch if equal

Question 30

What are Branches?

Answer 30

Conditional transfers of control Branch distance from the incremented PC value fits into the immediate field ## Footnote Includes loops and if statements

Question 31

What does I-Type instruction refer to?

Answer 31

Immediate Type ## Footnote Includes branches

Question 32

What does J-Type intruction refer to?

Answer 32

Jump Type ## Footnote Includes jumps

Question 33

Name features of procedures?

Answer 33

Easier to understand and code reuse Function can be worked on without working on the main body of the code

Question 34

What is the function of procedures?

Answer 34

Acquires resources, performs the tasks, covers tracks, return to the point of the origin with the desired result

Question 35

What regisiters are allocated for procedure calling?

Answer 35

$a0 - $a3 $v0 - $v1 $ra

Question 36

How are: $a0 - $a3 used in procedure calling?

Answer 36

Argument registers in which to pass parameters

Question 37

How are: $v0 - $v1 used in procedure calling?

Answer 37

Value registers in which to return values

Question 38

How are: $ra used in procedure calling?

Answer 38

Return address register to return to the point of origin

Question 39

What is jal used in and what does it do?

Answer 39

Used in procedures Jumps and links instructions

Question 40

What does: bne mean?

Answer 40

Branch if not equal ## Footnote Used in R-Type instruction

Question 41

What does: beq mean?

Answer 41

Branch if equal ## Footnote Used in R-Type instruction

Question 42

What does: blt mean?

Answer 42

Branch if less than ## Footnote Used in R-Type instruction

Question 43

What does: ble mean?

Answer 43

Branch of less than or equal to ## Footnote Used in R-Type instruction

Question 44

What does: bgt mean?

Answer 44

Branch if greater than ## Footnote Used in R-Type instruction

Question 45

What does: bge mean?

Answer 45

Branch if greater than or equal to ## Footnote Used in R-Type instruction

Question 46

What does: slt mean?

Answer 46

Set on less than ## Footnote Used in R-Type instruction

Question 47

What does: slt $t0, $s0, $s1 mean?

Answer 47

if $s0 < $s1 then $t0 = 1 else $t0 = 0 ## Footnote Used in R-Type instruction

Question 48

What is $zero

Answer 48

A constant

Question 49

What does: j label do?

Answer 49

Jumps tot he nect instruction called label