8086 TECHNICAL INTERVIEW QUESTIONS.

What is the difference between 8085 and 8086 in microprocessor?

·         8086 has a special concept called as memory segmentation. It allows parallel processing, while 8085 does not.

·         8085 is a 8-bit micro processor,8086 is a 16-bit processor

·         8086 can have 20-bit address bus
8085 can have 16-bit address bus

What are the flags in 8086?

In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.

What are the various interrupts in 8086?

Maskable interrupts, Non-Maskable interrupts.

What is Non-Maskable interrupts? 

An interrupt which can be never be turned off (ie.disabled) is known as Non-Maskable interrupt.

Which interrupts are generally used for critical events? 

Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.,

What is the Maximum clock frequency in 8086?

The clock frequency was originally limited to 5 MHz (IBM PC used 4.77 MHz), but the last versions in HMOS were specified for 10 MHz.

What are the various segment registers in 8086? 

Code, Data, Stack, Extra Segment registers in 8086.

What do u mean by assembler?

Assembler, for an assembly language, a computer program to translate between lower-level representations of computer programs. An assembler converts basic computer instructions into a pattern of bits which can be easily understood by the computer and the processor can use it to perform its basic operations.

What do u mean by linker?

In computer science, a linker or link editor is a program that takes one or more objects generated by a compiler and combines them into a single executable program.

What do u mean by compiler?

A compiler is a computer program (or set of programs) that transforms source code written in a programming language (the source language) into another computer language (the target language, often having a binary form known as object code). The most common reason for wanting to transform source code is to create an executable program.

What do u mean by emulator?

An emulator is hardware and/or software that duplicates (or emulates) the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system.

What is meant by cross-compiler?

A cross compiler is a compiler capable of creating executable code for a platform other than the one on which the compiler is run. Cross compiler tools are used to generate executables for embedded system or multiple platforms.

What is assembler directives?

An assembler directive is a message to the assembler that tells the assembler something it needs to know in order to carry out the assembly process

eg: EQU,ORG,END

Which Segment is used to store interrupt and subroutine return address registers?  Stack Segment in segment register is used to store interrupt and subroutine return address registers.

Which Flags can be set or reset by the programmer and also used to control the operation of the processor?

Trace Flag, Interrupt Flag, Direction Flag.

What does EU do?

Execution Unit receives program instruction codes and data from BIU, executes these instructions and store the result in general registers.

Which microprocessor accepts the program written for 8086 without any changes?  8088

What is the difference between 8086 and 8088?

The BIU in 8088 is 8-bit data bus & 16- bit in 8086.Instruction queue is 4 byte long in 8088and 6 byte in 8086.

What are the different functional units in 8086?
Bus Interface Unit and Execution unit, are the two different functional units in 8086

Logic calculations are done in which type of registers?
Accumulator is the register in which Arithmetic and Logic calculations are done.

How many pin IC 8086 is? – 40 Pin

What is 8087? How it is different from 8086?

The Intel 8087, announced in 1980, was the first floating-point coprocessor for the 8086 line of processors;

Why 8085 processor is called an 8 bit processor? –

Because 8085 processor has 8 bit ALU (Arithmetic Logic Unit). Similarly 8086 processor has 16 bit ALU.

What is 1st / 2nd / 3rd / 4th generation processor? –

The processor made of PMOS / NMOS / HMOS / HCMOS technology is called 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.

Define HCMOS? –

High-density n- type Complementary Metal Oxide Silicon field effect transistor.

Differentiate between RAM and ROM? –

RAM: Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Volatile Memory.

Difference between static and dynamic RAM?

Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop. Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.

Can ROM be used as stack? –

 ROM cannot be used as stack because it is not possible to write to ROM.

In memory mapped I/O system which of the following instruction will not be there

1. LDA  2. STA 3.ADD  4.OUT        Ans : OUT

Maximum no of bits required in the ASCII table set is – 7 bits

Describe segmentation & pipelining in 8086.

What is the size of data bus in 8086?

What is the size of address bus in 8086?

What is the max memory addressing capacity of 8086?

What is the size of flag register?

How many bit combinations are there in a byte?