CENTRAL PROCESSING UNIT (CPU).- CPU IS THE HEART OF THE WHOLE SYS-...
1. Central Processing Unit (CPU).
- CPU is the heart of the whole sys
- CPU consists of the :
• control unit (CU)
• arithmetic logic unit (ALU)
• accumulator (ACC)
• program counter (PC)
• instruction register (IR)
• memory address register (MAR)
• memory data register (MDR)
• status register (SR)
• general purpose register
- The function of each components of CPU:
• Control unit:
control and co_ordinate all hardware functions of the CS.
examine and decode all program instructions to the computer and
initiate their execution by sending the appropriate signals.
• ALU:
performs all arithmetic <addition, subtraction, multiplication,
division & exponentiation> and logic comparision two values
functions required by computer.
• ACC:
holds the first operand of the temporary result of the ALU.
• PC:
contains the add of the next instruction to be excuted.
• IR:
contains the current instruction to be executed.
Main memory
• MAR:
holds the address location to or from which data is to be transferred
• MDR:
contains the data to be written to or read out of the addressed
location.
• SR:
keeps track of the status of the accumalator.
• General Purpose Register:
for general purpose procedures.
Please refer to diagram for an illustratin of the basic components of the CPU.
CPU
I
N
Control unit
T
Arithmetic Logic Unit
E
R
Accumulator
Program Couter to main
A
L
Instruction Register memory
B
Memory Address Register
U
S