Explain about indexed addressing scheme, Computer Engineering

Assignment Help:

In this technique, operand field of instruction includes an address and an index register thatcomprises an offset. This addressing scheme is normally used to address the consecutive locations of memory (that may store the elements of an array). Index register is a special CPU register which contains an index value. Contents of the operand field A are taken to be address of the initial or reference location (or first element of array). The index register specifies distance between the starting address and address of that operand. 

For illustration: to address of an element B[i] of an array B[1], B[2],....B[n] with every element of array stored in two consecutive locations and starting address of array is presumed to be 101, the operand field A in instruction shall comprises the number 101 and index register R will contain the value of expression (i - 1) × 2. 

So for first element of the array index register will hold 0. For addressing 5th element of the array A=101 while index register will hold:

(5- 1) × 2 = 8

So address of 5th element of array B is=101+8=109. In B[5] but the element will be stored in location 109 and 110. To address any other element of array changing the content of index register will serve. 

So the effective address in this technique is calculated as:

EA = A +(R)

D = (EA)

(DA is Direct address)

As the index register is employed for iterative applications so the value of index register is decremented or incremented after each reference to it. In numerous systems this operation is performed automatically at the time of the course of an instruction cycle. This feature is termed as auto-indexing. Auto indexing can be auto-decrementing or auto-incrementing. The choice of register to be employed as an index register varies from machine to machine. Some machines use general-purpose registers for this purpose whereas other machines can specify special purpose registers referred to as index registers.

1400_Explain about Indexed Addressing Scheme.png

Figure: For Displacement Addressing


Related Discussions:- Explain about indexed addressing scheme

C token, describe briefly about the c token with suitable example program

describe briefly about the c token with suitable example program

State a simple pull transaction, a. Explain the future of mobile commerce i...

a. Explain the future of mobile commerce in world? b. 'Push and Pull' are two ways of transferring information to and from a phone, through WAP. Now, with the help of diagram, s

Concept of multithreading, Concept of Multithreading: This problem ris...

Concept of Multithreading: This problem rises in design of large scale multiprocessors like MPP. So a solution for optimizing this latency must be acquired at. The idea of Mul

Convert, haw to convert context free grammar to regular grammar

haw to convert context free grammar to regular grammar

Example of pruning, Example of Pruning: As an example, we are assume t...

Example of Pruning: As an example, we are assume that the four choices for player one, there we are looking only two moves ahead 1 for player one and 1 for player two such as

Explain icw, Question 1 What are the drivers behind the convergence betwee...

Question 1 What are the drivers behind the convergence between voice and data networks? Explain them briefly Question 2 Explain the need and functioning of Private ST Netw

What is micro programmed control, What is micro programmed control? Mic...

What is micro programmed control? Micro programmed control is a scheme in which control signals are formed by a program same to machine language program.

Database system, What are the three data anomalise that are likely to occur...

What are the three data anomalise that are likely to occur as a result of data redundancy?

Experiment with neural network, Assignment 3.b: Experiment with Neural Netw...

Assignment 3.b: Experiment with Neural Network Background: In this assignment, you will experiment with neural network for solving different types of practical problems. Y

Example of calculate maximum access time & cost of switch, Calculate the ma...

Calculate the maximum access time that can be permitted for the data and control memories in a TSI switch with a single input and single output trunk multiplexing 2500 channels. Al

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd