While the operating frequency of 8086 microprocessor is 5 mhz, also the advanced version of 8086 microprocessor operates at a frequency about 8 and 10 mhz also. The term 16 bit means that its alu,its internal registers and most of the instructions are designed to work with 16 bit binary words. Features of 8086the most prominent features of a 8086 microprocessor are as follows. Flag register contains information reflecti ng the current status of a microprocessor.
Flag register of 8086 flags register determines the current state of the processor. The 8086 processor architecture comprises a memory structure, a register structure, an instruction set, and an external interface. This information indicates which relocation register is presently being used for. Unit1 introduction to 8086 ece department microprocessors and microcontrollers page 1 uniti introduction to 8086 contents at a glance. Microprocessors and microcontrollers page 1 unitii 8086 assembly language programming. All the instructions which directly effect the flag register come under this group of. With the register addressing mode the operand to be accessed is specified as residing in an internal register of the 8086. Unlike the 8085, the 8086 microprocessor has a 20bit address bus. The most prominent features of a 8086 microprocessor are as follows. The general purpose registers, can be used either 8bit registers or 16bit registers used for holding the data, variables and intermediate results temporarily or for other purpose like counter or for storing offset address for some particular addressing modes etc. It has an instruction queue, which is capable of storing six instruction bytes from the memory resulting in faster processing. As you know, the microprocessor performs arithmetic and logical operations.
Register organization of 8086 intel 8086 microprocessor. Pdf multiple choice questions on 8086 microprocessor. Microprocessor is a controlling unit of a microcomputer, fabricated on a small chip capable of performing alu arithmetic logical unit operations and communicating with the other devices connected to it. E,mcet pathanamthitta intel 80186 80186 contain a 16bit data bus. Register structure the 8008 processor contains two register files and four 1bit flags. Generalpurpose microprocessor used in general computer system and can be used. If this flag is set, the processor enters the single step execution. In 8086 microprocessor, memory is divided into 4 segments as follow. General purpose registers in 8086 microprocessor geeksforgeeks. The 14 registers of 8086 microprocessor are categorized into four groups. Eu contains control circuitry, instruction decoder, alu, pointer and index register.
Description of general data registers,segment registers and pointers and index registers of intel 8086 microprocessor and brief introduction of flags. Microprocessor consists of an alu, register array, and a control unit. It was the first 16bit processor having 16bit alu, 16bit registers, internal data bus, and 16bit external data bus resulting in faster processing. The 8086 microprocessor is internally divided into two separate functional unit. This microprocessor had major improvement over the execution speed of 8085. Instead, the cpu generally manipulates these registers directly. Lecture 3 brief history and registers of 80x86 family. A microprocessor is an integrated circuit with all the functions of a cpu however, it cannot be used stand alone since unlike a microcontroller it has no memory. On these lines the cpu sends out the address of the memory location that is to be written to or read from. Ibm selected the intel 8088 for their personal computer ibmpc.
The 8086 is a 16bit microprocessor and was developed in 1978 by intel. Microprocessor and microcontrollers notes pdf 2021 btech. Unit1 introduction to 8086 ece department microprocessors and microcontrollers page 2 iv address bus. Tutorial on introduction to 8085 architecture and programming. The source can be a register, a memory location or an immediate number. The only difference is that the 80186 contain additional reserved. It has a 16bit alu with 16bit data bus and 20bit address bus. If this flag is set, the markable interrupts are recognized by the cpu, otherwise they are ignored. The remaining components in the system are latches, transceivers, clock generator, memory and io devices. R8 r15found in the pentium 4 and core2 if 64 eflag and flag register the eflag and flag register counts for the entire 8086 and pentium microprocessor family. The address bus consists of 16, 20, 24, or more parallel signal lines. The intel 8086 is a 16bit microprocessor intended to be used as the cpu in a microcomputer.
It was the first 16bit processor having 16bit alu, 16bit registers, internal data bus, and 16bit external data bus resulting in. In 8086 microprocessor the following has the highest priority among all type interrupts. There is a single microprocessor in the minimum mode system. General purpose registers are used to store temporary data within the microprocessor. Flag register of 8086 microprocessor geeksforgeeks. A microprocessor is a multipurpose, programmable, clock driven, register based electronic device that reads binary information from a storage devic e called memory, accepts binary data. In 1978, intel introduced the 16 bit microprocessor 8086 and 8088 in 1979. This unit fetches instructions, reads data from memory and. A microprocessor requires a external memory for programdata storage. Interacting of memory and io devices are shown with the basic minimum mode 8086 configuration. They are modified automatically by cpu after mathematical operations, this allows to determine the type of the result, and to determine conditions to transfer control to other parts of the program. The major parts are the central processing unit or cpu, memory, and the input and output circuitry or io.
Pdf microprocessors and interfacing by douglas hall. You do not access these registers the same way you access the other 8086 registers. The 80858080a has six generalpurpose registers to store 8bit data. Dx register is used to contain io port address for io instruction. Encoding of 8086 instructions 8086 instructions are. An interrupt is the method of processing the microprocessor by peripheral device.
A course material on microprocessor and microcontroller. Both the source and the destination operands have been specified as the contents of internal registers of the 8086. The internal register structure of the 80186 is virtually identical to the 8086. Registerstructure the8008processorcontainstworegisterfilesandfour1bitflags.
But because the 4004 was designed for serial bcd arithmetic while the. And an 8086 microprocessor is able to perform these operations with 16bit data in one cycle. Mov ax, bx this stands for move the contents of bx the source operand to ax the destination operand. Introduction of registers of 8086 microprocessor youtube. Microprocessor and interfacing notes pdf mpi pdf notes book starts with the topics vector interrupt table, timing diagram, interrupt structure of 8086. They are the instruction pointer, four data registers, four pointer and index register, four segment registers. The destination can be a register or a memory location. An interrupt is used to cause a temporary halt in the execution of program. Note that there are two legal encodings of pop reg shorter form exists because pops are so common most assemblers will use the shorter form pop segment register.
The 8086 had eight more or less general 16bit registers including the stack pointer, but excluding the instruction pointer, flag register and segment registers. Biu has segment registers, instruction pointer, address generation and bus. It also contains informat ion which controls the operation of the microprocessor. Antonakos, an introduction to the intel family of microprocessors, third edition, prentice hall, 1999. Unit i introduction to intel microprocessor 8086 overview of.
There are 8 general purpose registers in 8086 microprocessor. The 80286 cpu contains almost the same set of registers, as in 8086, namely. Pdf ee8551 microprocessors and microcontrollers mcq. Both of these first microprocessors were complete cpusonachip and had similar characteristics. D2, d4, d6, d7 and d11 are called as status flag bits. The figure shows the typical minimum mode 8086 system. Registers the 80858080aprogramming model includes six registers, one accumulator, and one flag register, as shown in figure. Most of the registers contain datainstruction offsets within 64 kb memory segment. Thus, another design goal was direct addressing of more than 64k bytes and support of multiprocessor configurations. Segment registers additional registers called segment registers generate memory address when combined with other in the microprocessor. The8080registersarethesameseven 8bitregistersthatwereinthe8008scratchpad namelya,b,c, d,e,h,andl.
The architecture of 8086 supports a 16 bit alu, a set of 16 bit registers and provides the segmented memory addressing capability, a rich. Unlike, 8085, an 8086 microprocessor has 20bit address bus. The term 16bit means that its arithmetic logic unit, internal registers, and most of its instructions are designed to work 16bit binary words. Microprocessor responds to the interrupt with an interrupt service routine, which is short program or subroutine that instructs the microprocessor on how to handle the. The latest incarnation, the itanium, is the first of a completely new architecture that emulates the 8086. The top portion of the programming model contains the general purpose registers.
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