stucture and function of the processor Flashcards
1.1.1
what is the control unit ?
the role of the control unit is to co-ordinate all activties in the cpu
what is the program counter?
the role of the program counter is to hold the address of the next instruction to be executed
what is the memory address register?
the role of the MAR is holds the address of the memory location
what is the memory data register ?
the role of the MDR is to store temporary data
what is the current instruction register ?
the role of the CIR is to hold the address of the current instruction being executed
-opcode & operand
what is the accumulator ?
this is where temporary arithmetic and logical data is stored
what is the arithmetic logic unit ?
this is where all arithmetic and logical operations are performed
e.g ADD,SUB,MULT
what is the data bus?
carries binary 1’s and 0’s
what is the address bus ?
carries memory addresses that identify when the data is being read from or writtren to
what is the control bus ?
carries control and command signals to every compartment
Describe the Fetch-Decode-execute cycle?
Fetch:
- The PC is checked as it holds the address of the next instruction
-the address is stored then copied to the MAR
- The address is then sent along the address bus to main memory
Decode:
- after decoding the instruction you will be able to find out what operation you need to do next.
execute :
- now the address is sent to the MDR
- then stored in the ACC
what is an instruction made out of ?
opcode + operand
opcode- what to do
operand = what to do it to
what are common factors that affect the performance of a CPU?
- Clock speed = this is the amount of cycles per second
-Amount of cache = this is where temporary data is stored
-Number of cores = A cpu has multiple cores , this can speed up the CPU however they all need to communicate with each other therefore it wastes time.
what is the pipelining technique ?
Pipelining is the technique of fetching an instruction whilst the prior one is being decoded and the one before that is being executed.
Describe the von-neumann structure ?
- shared memory space for instruction and data
-both stored in the same format
-one instruction at a time
describe the Harvard structure ?
-instructions and data are stored in seperate memory units
-each memory unit has its own bus
-reading and writting can be done at the same time
- used in RISC
differences between Von-neuhmann and Harvard structure ?
Von-neuhmann:
- used in embedded systems
-data and programs share the same memory
-one bus is used transfer data and instructions
Havard:
- used in portabel devices
-programs and data are held in seperate memory units
- programs tend to be large
what are registers ?
and list all 5 memory registers ?
registers are small memory cells that operate at high speeds.
-CIR , ACC,MDR,MAR,PC
Describe two ways in which the accumulator is used?
- Used to temporarily store mathmatical and logical programs
- responsible for input and output
state how a cpu determines if an interrupt has been raised?
The CPU determines if an interrupt has been raised after the program has been executed, after it has been executed, it will then detect an interrupt error.
