structure of the processor

Question 1

what does ALU stand for

Answer 1

Arithmetic Logic Unit

Question 2

what does CU stand for

Answer 2

Control Unit

Question 3

what does PC stand for

Answer 3

Program counter

Question 4

what does CIR stand for

Answer 4

Current Instruction Register

Question 5

what does MBR stand for

Answer 5

Memory Buffer Register

Question 6

what does MAR stand for

Answer 6

Memory Address Register

Question 7

what does SR stand for

Answer 7

Status Register

Question 8

what does GPR stand for

Answer 8

General Purpose Registers

Question 9

what does CPU stand for

Answer 9

Central Processing unit

Question 10

what is the role of the ALU

Answer 10

performs calculations such as ADD, OR and SHIFT operations

Question 11

what is the role of the CU

Answer 11

coordinates activities in the CPU, memory and peripherals
- controls operation of fetch - execute cycle
- synchronise operation of processor
- handle interrupts

Question 12

what are peripherals

Answer 12

external hardware devices that are not part of the CPU

Question 13

what is the role of the clock

Answer 13

continuous sequence of clock pulses to step the control unit through its operations

Question 14

what are the role of registers

Answer 14

very fast on chip memory for temporary storage of binary values

Question 15

what is the other item that is part of the structure of the processor

Answer 15

internal buses and logic gates

Question 16

what does the MBR do

Answer 16

temporarily stores data read from or written to memory

Question 17

what can be stored in the MBR?

Answer 17

it can be the next instruction to be fetched or data to be used in an instruction

Question 18

what bus does the MBR connect to

Answer 18

data bus. Its the processors direct connection to the data bus for accessing main memory

Question 19

what format are processor instructions in?

Answer 19

a simple format called machine code (binary)

Question 20

into what form can machine code be easily interpreted

Answer 20

assembly form

Question 21

what is the step in between the binary form and the assembly form

Answer 21

the decode step
eg
binary form: 0001 0001 0000 1111
(the decode step)
assembly form: ADD R1, # 15

Question 22

in the assembly form ADD R1, # 15, what is the operation code?

Answer 22

ADD

Question 23

in the assembly form ADD R1, # 15, what is the operand?

Answer 23

R1

Question 24

in the assembly form ADD R1, # 15, what is the other operand?

Answer 24

15

Question 25

what is the instruction set?

Answer 25

the set of binary codes for the machine operations that a processor has been designed to perform

Question 26

what are the roles of the GPR?

Answer 26

they have no specific purpose

Question 27

what can the GPR store

Answer 27

binary numbers

Question 28

what are the GPR usually used as

Answer 28

temporary storage when performing arithmetic functions

Question 29

what are GPR often?

Answer 29

they are often the operands of processor instructions

Question 30

what step is performed on the CIR

Answer 30

the 'decode' step

Question 31

what does the CIR do?

Answer 31

stores the current instruction (in binary)

Question 32

what does the PC do?

Answer 32

holds the address of the next instruction to be executed

Question 33

what does the MAR do?

Answer 33

holds the address of a memory location from which data will be read or data will be written to

Question 34

what bus connects to the MAR

Answer 34

address bus

Question 35

what address could be stored in the MAR

Answer 35

it could be the address of the next instruction to be fetched, or the address of data to be used in an instruction

Question 36

what does the SR contain

Answer 36

contains many bits that are set (1) or cleared (0) depending on the result of an instruction

Question 37

what is the value of a set bit in the SR

Answer 37

1

Question 38

what is the value of a cleared bit in the SR

Answer 38

0