The 8086 microprocessor is 16 bit register which consists of
16 bit data bus for the data processing and 20 bit address bus for the address calculation.
It consists of a word and byte. Byte uses only one location in the memory
whereas the word is stored on two consecutive locations. Double word requires 4
consecutive locations. The whole architecture is basically parted into two unit
i.e. is the BUS INTERFACE UNIT and EXECUTION UNIT.
BUS INTERFACE UNIT: this unit is basically responsible for
the address calculation and it takes input from the outside world and produces
the output. the program will be bought into the main memory and 6 bytes one at
a time will be loaded into the queue and then it will passed to the control
EXECUTION UNIT: this unit is responsible for executing the
instruction these instructions are passed to this unit by the ALU(the
arithmetic and logical unit) .this unit is responsible for carrying various arithmetic
instructions like ADD,ADC,SUB,SBB,MUL,DIV etc and logical instructions like
The 8086 microprocessor also consists of various segments
and the segment register. the 8086 consist 8 general purpose register and 8
special purpose registers. the 8086 microprocessor is divided into segments .the
various segments like the DS,CS,SS,ES,IP.the Data segment is responsible for
holding the data. the data required for the or by the program is stored into
the DS segment’s(code segment) it is where the code for the program is stored.SS(stack
segment) the stack operations are stored here.ES(Extra segment)this segment is
nothing but an extension of the data segment if the data segment is full then
the extra segment Is used to store the data. Each segment in the 8086
microprocessor is 64 kb in size.
The 8086 microprocessor also consist of various flags. they
are control and data flags for the smooth writing of the program.