Structure and Function of the proccessor Flashcards
Control unit
The part of the processor that co-ordinates the activity of all other components
Control signals are sent along the control bus between the control unit and the other components of the computer
Controls signals include
Memory read-data in adress location to be placed on the data bus
Memory write-data on data bus is written on RAM
Bus request -indicates that a device is requesting the use of the data bus
Bus grant-indicates that the CPU has granted access to the data bus
Clock-used to synchronize operations
ALU
Problem solving part of the processor
performs arithmetic,logical and shift operations on data
The accumulator
Where the results of the calculation made by the ALU are
All 1/0 geos through accumulator
PC
Program counter- keeps track of the memory location of the line of machine code being executed.
Contains the address of the next instruction that is needed to be fetched /carried out
MDR
The memory data register stores the data that has been fetched from or stored in memory
copy of MAR
Contains data currently used by the processor
MAR
the memory address register stores the address of the data or instructions that are to be fetched from or sent to
copied from PC
address of memory location
may be address of next instruction
CIR
Contains the address of the current instruction being executed
its copied from the MDR
It contains data cache and instruction cache
FETCH DECODE EXECUTE cycle:FETCH
the address of the next instruction is copied from the PC to the MAR
The instruction held at that address is copied to the MDR simultaneously the content of the PC is incremented so that it holds the address of the next instruction
The contents of the MDR are copied to the CIR
FETCH DECODE EXECUTE cycle:DECODE
teh instruction held in teh CIR is decoded.The instruction is split into opcode and operand and teh opcode is used to determine teh type of instruction and what hardware to use to execute it to The operand holds either:
The address of teh data to be used with teh operation,which is then copied to teh MAR or
teh actual data to be operated on,which will be copied to the MDR
The data to be operated in may be passed to teh ALU
FETCH DECODE EXECUTE cycle:EXECUTE
The appropriate instruction/opcode is carried out on the operand
What is clock speed?
A series of ON/OFF signals used to synchronize the operations of the processor components
How does clock speed affect the processor?
Since the Fetch execute cycle is triggered by thr clock pulse of the system clock.The faster the clock speed the faster a computer can fetch decode and execute instructions
What is a dual core processor?
A dual-core processor has two processors linked together in the same integrated circuit
How does the number of cores affect the processor?
each core is theoretically able to process a different instruction at the same time with its own fetch-execute cycle making a quad core computer two or even four times faster than a single-core computer.
