x86 Interview Questions And Answers

A blocking assignment is one in which the statements are executed sequentially, i.e. first statement is executed and variable is assigned a value then second is executed and so on. A non blocking assignment is one in which statements occurs concurrently. Only nonblocking assignments should be used in sequential circuit.

e.g
initial
begin
a=b; //blocking
c<=a; //nonblocking
d=c; //blocking
end

In this example firstly the value of b is assigned to a and this value is assigned to c only after execution of first statement. The second and the third statements are executed simultaneously, i.e. value a is assigned to c and previous value if c is assigned to d.

For D Latch:always@(enable)q<=d;
For D flip flop:always@(posedge clock)q<=d;

and gate

30 days.Explanation:Before:One day work = 1 / 20One man?s one day work = 1 / ( 20 * 75)Now:No. f workers = 50One day work = 50 * 1 / ( 20 * 75)The total no. of days required to complete the work = (75 * 20) / 50 = 30.

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

Stack is a portion of RAM used for saving the content of Program Counter and general purpose registers.

LIFO stacks, also known as "push down" stacks, are the conceptually simplest way of saving information in a temporary storage location for such common computer operations as mathematical expression evaluation and recursive subroutine calling.

Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently

A software or hardware mark that signals a particular condition or status. A flag is like a switch that can be either on or off. The flag is said to be set when it is turned on.

All x86 processors have pipelined structure.

Compiler is used to translate the high-level language program into machine code at a time. It doesn?t require special instruction to store in a memory, it stores automatically. The Execution time is less compared to Interpreter.

A compiler is a program that translates a source program written in some high-level programming language (such as Java) into machine code for some computer architecture (such as the Intel Pentium architecture).

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

Floating ?gate Avalanche Injection MOS (FAMOS) transistor is used in each cell of EPROM.

Cache Memory is scratch pad of computer.

Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.

Cache memory is random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM. As the microprocessor processes data, it looks first in the cache memory and if it finds the data there.

Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.

A signal informing a program that an event has occurred. When a program receives an interrupt signal, it takes a specified action (which can be to ignore the signal).

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.

In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.

If for a short period of time circuits goes to some different logic level then it is supposed to have then it is called static hazard.e.g. If the final logic value of output of a given circuit becomes one even if it is supposed to be zero then it is called Static-0 Hazard and vice versa. Dynamic Hazard is the one in which the circuit output goes to some other logic level more than once then finally settling down to some appropriate level.

Latch is a D- type flip-flop used as a temporary storage device controlled by a timing signal, which can store 0 or 1. The primary function of a Latch is data storage. It is used in output devices such as LED, to hold the data for display.

To Store monitor programs.

In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions, and also it is defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.

the basic architectural difference is that microcontroller has an programmable memory while it is not the case with microprocessors.

It has limitations on the size of data. Most Microprocessor does not support floating-point operations.

The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.

The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.

The processing speed depends on DATA BUS WIDTH.

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

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.