Question: architecture diagram of 8086 microprocessor
Answer :
Bus Interface Unit (BIU)
The Bus Interface Unit (BIU) manages the data, address and control buses.
Fetches the sequenced instruction from the memory,
It read & write data from memory & ports.
It is called the external world interface to the processor.
Register Bank (Segment Register) :
Code segment register: It is a 16-bit register and holds the address of the instruction or program stored in the code segment of the memory.
Stack segment register: The stack segment register provides the starting address of stack segment in the memory. Like in stack pointer, PUSH and POP operations are used in this segment to give and take the data to/from it.
Data segment register: It holds the address of the data segment. The data segment stores the data in the memory whose address is present in this 16-bit register.
Extra segment register: Here the starting address of the extra segment is present. This register basically contains the address of the string data.
Execution Unit (EU) :
The Execution Unit (EU) performs the decoding and execution of the instructions that are being fetched from the desired memory location.
Control Unit :
the control unit in 8086 microprocessor produces control signal after decoding the opcode to inform the general purpose register to release the value stored in it. And it also signals the ALU to perform the desired operation.
Arithmetic & Logic Unit (ALU) :
it perform an arithmetic & logical operation.
It will also set / reset the appropriate flag according to the result of operation.
Flag Register :
A flag is a flip- flop which indicates some condition produced by an execution of instruction.
Stack Pointer (SP) :
It is 16-bit register. Used to store 16-bit effective address of the top of the stack.
Base Pointer Register (BP) :
It is 16-bit register used to store effective address.
Source Index (SI) Register & Destination Index (DI) Register :
Both are 16-bit register.
It provide autoincrement & autodecrement facility.
They are used for string operation.
General Purpose Register :
Four 16-bit register with name AX, BX, CX, DX are available.
All there registers can be used as two 8-bit registers.
It’s basic function is to store data temporarily