Intel 8086 is a 16-bit microprocessor developed by Intel in the year between early 1976 and mid-1978 and released in 1978. It is an advanced version of the Intel 8080 microprocessor. The 8086 microprocessor had a significant impact on the computer industry as it was the first processor to use the x86 instruction set architecture (ISA). The x86 ISA is still used in most modern processors.
The 8086 microprocessor has a complex architecture that consists of several functional blocks. The architecture includes registers, data bus, address bus, control unit, and arithmetic and logic unit (ALU) etc.
Registers:
The registers are used to store data and instructions during the execution of a program. The registers can be classified into three categories: general-purpose registers, segment registers, and index registers.
Data Bus:
Data bus is used to transfer data between the processor and memory or input/output (I/O) devices.
Address Bus:
Address bus is used to identify the memory location or I/O device to be accessed.
Control Unit:
The control unit is responsible for controlling the flow of data and instructions within the processor. It retrieves instructions from memory and decodes them so that the arithmetic and logic unit can execute them.
Arithmetic and Logic Unit (ALU):
The ALU is responsible for performing arithmetic and logical operations on data. It can perform operations such as addition, subtraction, multiplication, division, and logical operations like AND, OR, and XOR.
Modes of Operation:
The 8086 microprocessor has two modes of operation: minimum mode and maximum mode. In the minimum mode, the 8086 microprocessor is used in a simple system that has only one processor. The minimum mode is used in applications that do not require the use of external coprocessors. In the maximum mode, the 8086 microprocessor is used in a complex system that has multiple processors and external coprocessors. The maximum mode is used in applications that require high-speed data processing and complex calculations.
Features of Intel 8086 Microprocessor:
- The 8086("eighty eighty-six") is also called iAPX 86
- Most popular and successful product by Intel
- Package: 40 pin dual inline pack (DIP)
- Maximum CPU clock rates 5 MHz to 10 MHz
- Instruction set: x86-16
- 16 bits ALU (Arithmetic Logic Unit)
- 16 bits data bus or path
- 20 bits address bus (The address refers to a byte in memory)
- The 8086 has eight more or less general 16-bit registers (including the stack pointer but excluding the instruction pointer, flag register and segment registers). Four of them, AX, BX, CX, DX, can also be accessed as twice as many 8-bit registers )while the other four, BP, SI, DI, SP, are 16-bit only.
- 8086 has a 16-bit flags register. Nine of these condition code flags are active, and indicate the current state of the processor: Carry flag (CF), Parity flag (PF), Auxiliary carry flag (AF), Zero flag (ZF), Sign flag (SF), Trap flag (TF), Interrupt flag (IF), Direction flag (DF), and Overflow flag (OF).
- Segment registers are also 16 bit
Applications:
The 8086 microprocessor has been used in a wide range of applications, including personal computers, industrial control systems, and embedded systems. The microprocessor has also been used in scientific equipment and medical devices.
The Intel 8086 microprocessor was a significant advancement in the computer industry. It introduced the x86 instruction set architecture, which is still used in modern processors. The microprocessor's complex architecture and modes of operation have made it suitable for use in a wide range of applications.
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