Thursday 31 January 2008

COMP 372 Assgn. # 4 Role Of Microprocessor in Computer

The simplified model of a microprocessor consists of five parts, which are:

Arithmetic & Logic Unit (ALU)
The part of the central processing unit that deals with operations such as addition, subtraction, and multiplication of integers and Boolean operations. It receives control signals from the control unit telling it to carry out these operations. For more, click the title above.

Control Unit (CU)
This controls the movement of instructions in and out of the processor, and also controls the operation of the ALU. It consists of a decoder, control logic circuits, and a clock to ensure everything happens at the correct time. It is also responsible for performing the instruction execution cycle. More on the control unit can be discovered by clicking the title above.

Register Array
This is a small amount of internal memory that is used for the quick storage and retreival of data and instructions. All processors include some common registers used for specific functions, namely the program counter, instruction register, accumulator, memory address register and stack pointer. For more, click the title above.

System Bus
This is comprised of the control bus, data bus and address bus. It is used for connections between the processor, memory and peripherals, and transferal of data between the various parts. Click the title above for more.

Memory
The memory is not an actual part of the CPU itself, and is instead housed elsewhere on the motherboard. However, it is here that the program being executed is stored, and as such is a crucial part of the overall structure involved in program execution.




























The ALU, or the arithmetic and logic unit, is the section of the processor that is involved with executing operations of an arithmetic or logical nature. It works in conjunction with the register array for many of these, in particular, the accumulator and flag registers. The accumulator holds the results of operations, while the flag register contains a number of individual bits that are used to store information about the last operation carried out by the ALU. More on these registers can be found in the register array section.

The control unit is arguably the most complicated part of this model CPU, and is responsible for controlling much of the operation of the rest of the processor. It does this by issuing control signals to the other areas of the processor, instructing them on what should be performed next.

A register is a memory location within the CPU itself, designed to be quickly accessed for purposes of fast data retrieval. Processors normally contain a register array, which houses many such registers. These contain instructions, data and other values that may need to be quickly accessed during the execution of a program.

The system bus is a cable which carries data communication between the major components of the computer, including the microprocessor.

Reference
http://www.eastaughs.fsnet.co.uk/cpu/structure-bus.htm

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