Microprocessor Questions with Answers
1.What is a Microprocessor?
Microprocessor
is a CPU fabricated on a single chip, program-controlled device, which fetches
the instructions from memory, decodes and executes the instructions.
2.
What is Instruction Set?
It
is the set of the instructions that the Microprocessor can execute.
3. What is
Bandwidth ?
The number
of bits processed by the processor in a single instruction.
4.
What is Clock Speed ?
Clock
speed is measured in the MHz and it determines that how many instructions a
processor can processed. The speed of the microprocessor is measured in the MHz
or GHz.
5. Difference
between JMP and JNC?
A:-JMP
is Unconditional Branch. JNC is Conditional Branch.
6.
What is Logical Address:?
A memory address
on the 8086 consists of two numbers, usually written in hexadecimal and
separated by a colon, representing the segment and the offset.
This combination of segment and offset is referred to as a logical
address
Logical address=segment: offset
7. What is The Effective
Address:
• In general, memory
accesses take the form of the following example:
• Mov ax, [baseReg + indexReg + constant]
• This example copies a word
sized value into the register AX.
• Combined, the three parameters
in brackets determine what is called the effective address,
which is simply the offset referenced by the instruction
8.
What is Physical Address?
Physical memory address pointed by SEGMENT:OFFSET pair is
calculated as:
Physical address = (<Segment Addr> * 10) +
<Offset Addr>
9.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.
10.Why
crystal is a preferred clock source?
Because
of high stability, large Q (Quality Factor) & the frequency that doesn’t
drift with aging. Crystal is used as a clock source most of the times.
11.What
is Tri-state logic?
Three
Logic Levels are used and they are High, Low, High impedance state. The high
and low are normal logic levels & high impedance state is electrical open
circuit conditions. Tri-state logic has a third line called enable line.
12.What
happens when HLT instruction is executed in processor?
The
Micro Processor enters into Halt-State and the buses are tri-stated.
13.What
is Program counter?
Program
counter holds the address of either the first byte of the next instruction to
be fetched for execution or the address of the next byte of a multi byte
instruction, which has not been completely fetched. In both the cases it gets
incremented automatically one by one as the instruction bytes get fetched. Also
Program register keeps the address of the next instruction.
14.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.
15.Name
the processor lines of two major manufacturers?
High-end:
Intel - Pentium (II, III, 4), AMD - Athlon. Low-end: Intel - Celeron, AMD -
Duron. 64-bit: Intel - Itanium 2, AMD - Opteron.
16.How
many bit combinations are there in a byte?
Byte
contains 8 combinations of bits.
17.Have
you studied buses? What types?
There
are three types of buses. Address
bus: This is used to carry the Address to the memory to fetch either
Instruction or Data.
Data
bus : This is used to carry the Data from the memory.
Control
bus : This is used to carry the Control signals like RD/WR, Select etc.
18.What
is the Maximum clock frequency in 8086?
5
Mhz is the Maximum clock frequency in 8086.
19.What
is meant by Maskable interrupts?
An
interrupt that can be turned off by the programmer is known as Maskable
interrupt.
20.What
is Non-Maskable interrupts?
An
interrupt which can be never be turned off (ie. disabled) is known as
Non-Maskable interrupt
21.What
are the different functional units in 8086?
Bus
Interface Unit and Execution unit, are the two different functional units in
8086.
22.What
are the various segment registers in 8086?
Code,
Data, Stack, Extra Segment registers in 8086.
23.What
does EU do?
Execution
Unit receives program instruction codes and data from BIU, executes these
instructions and store the result in general registers.
24.Which
Stack is used in 8086? k is used in 8086?
FIFO
(First In First Out) stack is used in 8086.In this type of Stack the first
stored information is retrieved first.
25.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.
26.What
is SIM and RIM instructions?
SIM
is Set Interrupt Mask. Used to mask the hardware interrupts.
RIM
is Read Interrupt Mask. Used to check whether the interrupt is Masked or not.
27. What
are the 4 Segments?
A:-Code
Segment Register {CS} Data Segment Register {DS}
Extra
Segment Register {ES} Stack Segment Register{SS}
28.What
are the General Data Registers & their uses?
A:-
The Registers AX,BX,CX,DX are the general Purpose 16-bit registers.AX register
as 16-bit accumulator.BX register is used as an offset Storage.CX register is
used as default or implied counter.Dx register is used as an implicit operand
or destination in case of a few instructions.
29.What
are Segment Registers & their uses?
A:-There
are 4 Segment Registers Code Segment(CS),Data Segment(DS),Extra Segment(ES)
& Stack Segment(SS) registers.CS is used for addressing memory locationin
code.DS is used to points the data.ES refers to a segment which is essentially
in another data segment.SS is used fopr addressing stack segment of memory.
30. Explain
about Direction Flag?
A:-This
is used by string manipulation instructions.
If
this flag bit is 0 , the string is processed beginning from the lowest to the
highest address,i.e.,.Autoincrement mode. Otherwise,the string is processed from the highest
towards the lowest address,i.e.,.Autodecrementing mode.
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