Introduction to 8086 microprocessor

As a part of introduction to 8086 microprocessor, knowing the importance of processor is more important.
Wherever in this technical world, there is involvement of programming , that program can be executed only by the processor. No other device can execute a program other than processor.

Eg: Computers need programs so it definitely has a processor.

Traditional bulbs have no programming, so no requirement of processor. Click here for introduction to microcontroller 8051.

History of intel processors

Introduction to 8086 microprocessor also dealt with first generation of processors.

First generation:

Intel , A tech giant in today’s technical world. Intel has invented it’s first processor 4004 , which was released in 1971. This processor could do only 4 bit operations which mean it cannot add/subtract numbers from 0-15, assuming all numbers are positive. 

Second generation:

In 1972, Intel released its first commercial 8008 processor which is an 8-bit processor. Even this processor did not have a good range. So this processor was majorly used for controlling applications. During this time some other processor by motorola ( 6800 ) was much popular. 

Third generation:

In 1978, Intel came up with the 8086 processor which is a 16-bit processor. The speed of this processor was 4x than the second generation. This processor became very much popular for many applications. 

Fourth generation:

In the early 1980s Intel came with the 80386 processor which is a 32-bit processor, this processor was extremely used in CPU systems mostly. During this time even Motorola launched its 32bit processor. In the early 1990s Intel launched an 80586 processor named Pentium which was extremely faster till date. In 2000 Intel released the Pentium 4 processor which has 1.5Ghz of clock frequency.

Fifth generation:

In the mid 1990s a 64-bit processor was launched which could perform 64bit operations in one cycle.

Sixth generation:

This processor was launched in 2015. Skylake is the name for intel’s 6th generation processor. There are many models in this generation , which are mostly dual core and quad core( what is core, number of cores would be discussed in the 8086 series ). They have a clock frequency of 2-3Ghz. It has 8MB of cache memory. 

Seventh generation:

This processor was launched in 2016. Kaby lake is the code name for Intel 7th generation processors.

This processor is an advanced model of 6th generation , with more speed. This has little more clock frequency.

Eighth generation:

This processor was launched in 2017. There are many models in this generation , which are mostly six core processors( what is core, number of cores would be discussed in the 8086 series ). They have a clock frequency of 3-4Ghz. This generation of processors has 12MB cache memory. 

how does the processor work

Any processor basically performs the below operations in a cycle.

  • Fetching
  • Decoding
  • Executing

These three operations are performed and it makes one cycle. Any complicated processor performs these operations but they may have different architectures.

Whatever the programmer gives data , this data is in high level language ( sometimes in assembly language ), that high level language is converted into machine language by the program compiler. 

A compiler converts high level language to machine language.

The data is stored in the memory in the form of the machine language.

Fetching:

The processor fetches the data from the memory using buses. Refer introduction to microcontrollers to know about buses.

Decoding:

Decoding means understanding the operation from machine language( opcode ). Opcode means the instruction code in machine language.  

For eg:

Let us assume there is a 2 bit processor that performs addition, subtraction, multiplication and division.

opcodeInstruction
00Addition ( + )
01Subtraction ( – )
10Multiplication ( * )
11Division (/ )

The programmer types ‘+’ which is converted into machine language by the compiler, and while decoding, the processor needs to understand that it is an addition. This is decoding. 

In this example 2:4 decoder can be used.

There are three main components for processing 

  1. Processor
  2. Memory
  3. I/O ports
block diagram of a processor .

Bidirectional arrow shows buses that can read and write the data. There is no connection between i/o ports and memory, because directly data is not saved in memory, or directly data is not displayed without interfacing the processor. 

If the three components ( memory, processor, ports ) are embedded on a single chip then it is known as a microcontroller otherwise it is a microprocessor.

Read also 🙂

Pipelining in processors

Architecture of 8086

For more detailed refer wikipedia , introduction to 8086

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7 thoughts on “Introduction to 8086 microprocessor”

        1. roboticelectronics

          Please elaborate your query !
          Is the question why instructions are converted to opcodes ?
          Opcodes are the codes ( in binary ) that are understood by processor. Every instruction/data is converted into opcode ( this is done by compiler ).
          For instance : ADD R0,R1 ( this is an instruction ) this would have an unique opcode. Every instruction has different opcode.

    1. roboticelectronics

      Thank you!
      The whole series of 8086 would be amazing, hope you would love it.
      Any suggestions, doubts please let us know in comment box

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