Short Answer
The architecture of the 8086 microprocessor refers to the internal structure and organization of its components. It is a 16-bit microprocessor that can process 16-bit data and has a 20-bit address bus. It is divided into two main parts: the Execution Unit (EU) and the Bus Interface Unit (BIU).
In simple words, the 8086 architecture shows how different units work together to execute instructions. It allows faster processing by separating instruction fetching and execution, improving overall performance.
Detailed Explanation:
Architecture of 8086 microprocessor
The 8086 microprocessor is a 16-bit processor developed by Intel. Its architecture is more advanced compared to earlier processors like the 8085. It is designed to improve speed and efficiency by dividing the processor into two main functional units: the Execution Unit (EU) and the Bus Interface Unit (BIU). This division allows parallel processing, where one unit fetches instructions while the other executes them.
The 8086 has a 16-bit data bus and a 20-bit address bus, which allows it to access up to 1 MB of memory. This large memory space makes it suitable for more complex applications.
Execution unit
The Execution Unit (EU) is responsible for executing instructions. It contains the Arithmetic Logic Unit (ALU), general-purpose registers, and flag register. The EU performs arithmetic and logical operations and processes data.
The EU takes instructions from the instruction queue and decodes them. After decoding, it performs the required operation using the ALU. It also updates the flag register based on the result of operations.
The EU does not directly access memory. Instead, it communicates with the Bus Interface Unit to get instructions and data.
Bus interface unit
The Bus Interface Unit (BIU) is responsible for communication between the processor and external devices like memory and input/output devices. It handles all data transfer operations.
The BIU fetches instructions from memory and stores them in an instruction queue. This queue helps in faster execution because instructions are already available when needed.
The BIU also contains segment registers such as Code Segment (CS), Data Segment (DS), Stack Segment (SS), and Extra Segment (ES). These registers are used to access memory using segmentation.
Segmentation concept
The 8086 uses a memory segmentation technique to manage its large memory space. Memory is divided into segments, each of size up to 64 KB. Each segment has a starting address stored in a segment register.
The physical address is calculated by combining the segment address and offset address. This method allows efficient use of memory and supports larger programs.
Instruction queue and pipelining
The 8086 microprocessor uses an instruction queue to store upcoming instructions. This allows the processor to fetch new instructions while executing current ones.
This technique is known as pipelining and improves the speed of execution. It reduces waiting time and increases overall efficiency of the processor.
Registers in 8086
The 8086 has several registers, including general-purpose registers like AX, BX, CX, and DX. It also has pointer and index registers such as SP, BP, SI, and DI.
Segment registers (CS, DS, SS, ES) are used for memory segmentation. These registers help in storing data, addresses, and instructions during execution.
Advantages of 8086 architecture
The architecture of the 8086 provides several advantages. It allows faster processing due to parallel operation of EU and BIU. It supports a large memory space and efficient data handling.
The use of segmentation and pipelining improves performance and flexibility. These features make the 8086 suitable for more advanced computing tasks.
Conclusion
The architecture of the 8086 microprocessor is designed to improve speed and efficiency by dividing tasks between the Execution Unit and Bus Interface Unit. With features like segmentation and pipelining, it provides better performance and supports larger memory. Understanding this architecture helps in learning advanced microprocessor concepts.