The microprocessor is a small VLSI
(very large scale integration) chip with many pins. It processes information
and manage the exchange between the Input/Output units and main memory.
It is controlled by
a sequence of instructions called microprocessor program, and the result of
this program in sent to the appropriate periphiral (input and output).
The microprocessor
consists of the following sections:
- Several registers which stores data.
- Arithmatic and logic unit (ALU)
- Control and timing unit.
Registers:
Registers main
function is storing data, some of them can be used by the programmer and some
can not, and used only by the processor.
Most important
registers:
-
Accumulator: also known as A-register, is used for storing the results of
mathematical operations.
-
Instruction register: used to store the current instruction that are being
executed in the microprocessor.
-
Program counter: stores the address of the next instruction to be executed.
-
Buffer register: stores data temporarily.
-
Status register: stores the current state of the instruction that are being
executed at the microprocessor.
-
Stack pointer: points to (stores the location of) the place in the main memory
called stack.
ALU
This unit executes
the arithmetic and logical instructions.
