Biu and eu in 8086 microprocessor pdf microprocessor architecture divided in the biu has to interact with memory and of the programs and to carry out the required processing. 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 interrupt. The microarchitecture of the 8086 microprocessors employs parallel processingthat is, they are implemented with several simultaneously operating processing units. The 8086 cpu is divided into two independent functional units. The pins that differ with each other in the two modes are from pin24 to pin31 total 8 pins. Oflag iflag s flag dflag tflag zflag aflag pflag cflag 15 0 overflow direction interrupt trap sign zero auxilliary carry parity carry the flags register the use and manipulation of the flags register will be discussed in our treatment of 8086 assembly language.
Assembler directives, simple programs, procedures, and macros. The control flag enable or disable the certain operation of the microprocessor. Its successors, the eflags and rflags registers, are 32 bits and 64 bits wide, respectively. Due to the mismatch in the speed between the microprocessor and other devices, a set of latches and buffers are required to interface the microprocessor with other devices. It is a 40 pin c package fabricated on a single lsi chip. Instruction set of 8086 an instruction is a binary pattern designed inside a microprocessor to perform a specific function. In 8086 carry flag, parity flag, auxiliary carry flag, zero flag, overflow flag, trace flag, interrupt flag, direction flag, and sign flag. All the data, pointer, index and status registers are of 16 bits.
In 1978, intel introduced the 16 bit microprocessor 8086 and 8088 in 1979. What is difference between control flag and conditional flag. Unit1 introduction to 8086 ece department microprocessors and microcontrollers page 2 iv address bus. Figure 21a illustrates the internal architecture of the 8086 microprocessor. Apr 01, 2020 the agreement was signed in october of 1981, and it gave amd rights to secondsource 8086 and 8088 microprocessors. View and download intel 8086 specification sheet online. The 8086 also called iapx86 is a 16bit microprocessor chip designed by intel between early 1976 and mid1978. The memory, address bus, data buses are shared resources between the two processors. Standby i ccs e 500 ma max y bushold circuitry eliminates pullup. The zero status flag z is set to 1 if the result of an arithmetic or logical operation is.
To design an 8086 based system, it is necessary to know how to interface the 8086 microprocessor with memory and input and output devices. Typically smaller systems and contains a single microprocessor. Intel 8088 has the same alu,same registers and same instruction set as the 8086. The entire group of instructions that a microprocessor supports is called instruction set. Due to this 8086 processor control instruction will not respond to an interrupt signal on its intr input. Eight of the registers are known as general purpose registers i. Block diagram of intel 8086 features of 8086 microprocessor. Since 8085 operates in even parity, parity flag is set when the result of arithmetic and logical operation has even number of 1 s.
The status flag reflect the result of an operation executed by processor. The term 16bit means that its arithmetic logic unit, internal registers, and most of its instructions are designed to work 16bit binary words. If directional flag is set 1, then access the string data from higher memory location towards lower memory location. Programming exercises can be performed available kits. There would be two pin diagramsone for min mode and the other for max mode of 8086, shown in figs. The 8086 has three control flags namely tf, if and df. Microprocessor year of introduction word length bit memory addressing capacity. Flag register of 8086 microprocessor geeksforgeeks. The book in eighteen chapters provides a very brief overview of 8085 processors, followed by a detailed discussion of 8086 architecture, programming and interfacing concepts.
These are set or reset by the eu on the basis of the results of some arithmetic or logic. Let us take a look at the changes between 8085 series of microprocessors and 8086 series of microprocessors. Core microprocessor assembly language programming. Topics intel 8088 microprocessor, intel 8086 microprocessor, intel 8088 microprocesseur, intel 8086 microprocesseur, assemblage informatique, microcomputers publisher peterborough, n. Operating system processor, 8086 datasheet, 8086 circuit, 8086 data sheet. Execution unit gives instructions to biu stating from where to fetch the data and then decode and execute those instructions. Cheaper since all control signals for memory and io are generated by the microprocessor. Usually the letters l and h specify the lower and higher bytes. The 8086 microprocessor is a16bit, nchannel, hmos microprocessor.
Pdf multiple choice questions on 8086 microprocessor. An over view of 8085, architecture of 8086 microprocessor. The control flags are used to control certain modes of the cpu. This 8086 processor control instruction sets the interrupt flag to one. The trap flag allows the cpu to run in a single stepping mode. February 10, 2003 intel 8086 architecture 2 an x86 processor timeline 1971. Features of a microprocessor here is a list of some of the most prominent features of any microprocessor. The control signals for maximum mode of operation are generated by the bus controller chip 8788. Intel 8086 microprocessor is the enhanced version of intel 8085 microprocessor. There are 3 control flags in 8086 microprocessor and these are. Directional flag d this flag is specifically used in string instructions.
The microprocessor chips are available at low prices and results its low cost. Differences between 8085 and 8086 microprocessor in the changing world of technologies, the devices used are also changing. The agreement was executed in the beginning of 1982. Related questions what are the different types of flags in a microprocessor. Figure below shows the details of the 16 bit flag register of 8086 cpu. An interrupt is used to cause a temporary halt in the execution of program. Conditional flags represent result of last arithmetic or logical instruction executed. Unit i the 8085 and mega speed reading workbook pdf 8086 microprocessors. Microprocessor applications 6 hrs industrial application of 8257 3. Complement carry flag it complements the carry flag. Intels 4004 was the first microprocessora 4bit cpu like the one from cs231 that fit all on one chip.
Intel 8086 1978, 8mhz, 29,000 transistors stopgap 16bit processor, architected in 10 weeks extended accumulator architecture, assemblycompatible with 8080 20bit addressing through segmented addressing scheme november 2, 2005. Which register is used as a count register in 8086. Download microprocessor interview questions and answers pdf. Microprocessor and interfacing notes pdf mpi pdf notes. The microprocessor has multiple data type formats like binary, bcd, ascii, signed and unsigned numbers.
The 8086 microprocessor has a 16 bit register for flag register. M80c86m80c862 16bit chmos microprocessor military y pinforpin and functionally compatible to industry standard hmos m8086 y fully static design with frequency range from d. Maximum mode 8086 system here, either a numeric coprocessor of the type 8087 or another processor is interfaced with 8086. Microprocessor and interfacing pdf notes mpi notes pdf.
An overview of 8085, architecture of 8086, microprocessor, special functions of general purpose registers, 8086 flag register and function of 8086 flags. Flag registers intel 80868088 microprocessor conditional flags. Feb 03, 2018 two types of flag in 8086 microprocessor 1. Intended for the beginning programming student taking the first course on the 8086, a 16bit microprocessor manufactured by intel.
The flags register is the status register in intel x86 microprocessors that contains the current state of the processor. Conditional flag indicate the result of last executed arithmetic or logical operation. Amd 8086 microprocessors were fabricated in ceramic dip, plastic dip and plastic plcc packages at speeds 5, 8 and 10 mhz. Intel, alldatasheet, datasheet, datasheet search site for electronic components and. It has a powerful instruction set and it is capable to providing multiplication and division operations directly. Flag registers intel 8086 8088 microprocessor conditional flags. Dear readers, welcome to 8086 microprocessor objective questions have been designed specially to get you acquainted with the nature of questions you may encounter during your job interview for the subject of 8086 microprocessor mcqs. The operands are either the registers or memory locations immediate data depending upon the addressing mode. Introduction to 16bit microprocessor introduction to microcomputers introduction of 8086 block diagram of 8086 microprocessors based development system 2. Briefly explain the three different types of control flags for the 8086. Intel 16bit hmos microprocessor specification sheet. The wider registers retain compatibility with their smaller predecessors. Best 8086 microprocessor objective questions and answers. It contains flip flops which indicate the condition or the status of the result.
Where the hmos is used for highspeed metal oxide semiconductor. The fixed bits at bit positions 1, 3 and 5, and carry, parity, adjust, zero and sign flags are inherited from. 8086 internal architecture eu execution unit general purpose registers pointer registers index registers alu flags biu bus interface unit segment registers cs, ds, es, ss, ip queue memory addressing segment base offset. Which microprocessor accepts the program written for 8086 without any changes. The 8086 also called iapx 86 is a 16bit microprocessor chip designed by intel between early 1976 and june 8, 1978, when it was released. Microprocessor 8086 functional units tutorialspoint. This register has 9 flags which are divided into two parts that are as follows. The same year amd began volume production of 8086 cpus. This has a 20bit address bus and a 16bit address bus, while the 8088 has an 8 bit external data bus. For example the zero flag zf will set if the result of execution of an instruction is zero. All three of them can be user programmed to suit their needs. Al can be used as an 8bit accumulator for 8bit operations. The 8086 and 8088 can perform most of the operations but their instruction set is not able to perform complex mathematical operations, so in these cases the microprocessor requires the math coprocessor like intel 8087 math coprocessor, which can easily perform these operations very quickly.
These objective type 8086 microprocessor questions are very important for campus placement. Please turn off your ad blocker and reload this page. The remaining 7 flags marked u are undefined flags. Intel 8085 8bit microprocessor intel 8085 is an 8bit, nmos microprocessor. The first four registers are sometimes referred to as data registers. The microprocessor has a set of flags that either monitors the state of executing instructions or controls options available in its operation. The intel 8088, released july 1, 1979, is a slightly modified chip with an external 8bit data bus allowing the use of cheaper and fewer supporting ics, and is notable as the processor used in the original ibm pc design. This instruction resets the interrupt flag to zero. An interrupt is the method of processing the microprocessor by peripheral device. Instruction queue is 4 byte long in 8088and 6 byte in 8086. The control signals for maximum mode of operation are. Flag register in 8086 is a 16 bit register used to store 9 flag bit. On these lines the cpu sends out the address of the memory location that is to be written to or read from. Scasb says compare 8086 string instructions as bytes and scasw says compare strings as words.
Architecture, programming, and applications, 2nd 1997. When an operation is performed by alu the result is transferred on data bus and status of. The arithmetic instructions affect all the conditional code flags. The address bus consists of 16, 20, 24, or more parallel signal lines. It indicates some condition produced by the execution of an instruction. In 8086 microprocessor, the address bus is bit wide. The several functions of flag register in 8086 are as follows. The 8086 microprocessor internal architecture the intel 8086 is a 16bit microprocessor intended to be used as the cpu in a microcomputer. Register organization general data register the registers ax, bx, cx and dx are the general purpose 16bit registers.
So, 20it can address any one of 2 10485761 mega byte memory locations. It serves as a campanion text to ayalas the 8051 microcontroller. Flags register determines the current state of the microprocessor. But the only difference is 8088 has only 8bit data bus and 20bit address bus.
It has a 16bit alu with 16bit data bus and 20bit address bus. Control flags controls the operations of the execution unit. Addressing modes of the 99000 microprocessor architecture, software, and interface techniques, avtar singh, walter a. Microprocessors and interfacing is a textbook for undergraduate engineering students who study a course on various microprocessors, its interfacing, programming and applications. Ibm selected the intel 8088 for their personal computer ibmpc. This microprocessor had major improvement over the execution speed of 8085. Microprocessor 8086 assembly language programming pdf. Ax is used as 16bit accumulator, with the lower 8bits of ax designated as al and higher 8bits as ah. The flag register of 8085 microprocessor consists of 5 flags. Multiprocessor configuration overview tutorialspoint. Program control instructions in microprocessor 80868088. Unit2 8086 assembly language programming ece department microprocessors and microcontrollers page 5 to this type of instructions. Intel 8086 is built on a single semiconductor chip and packaged in a 40pin ic package.
909 1075 406 1482 254 1466 1069 489 212 921 1577 1101 240 1384 1073 1179 1068 535 1419 1025 756 1602 1578 841 207 230 850 1071 1321 1425 638 240 700 395 932 881 494