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

Explain meaning of each field format of icmp header, Give the format of ICM...

Give the format of ICMP header and explain meaning of each field. The format of ICMP header is given below: Internetwork Control Message Protocol (ICMP) ICMP H

Authentication verses firewall, How does an authentication system be differ...

How does an authentication system be different from a firewall into functioning? Authentication verses firewall User Authentication and Authorization A significan

Write a ''c'' functions to arrange the elements of an integer , Write a 'C'...

Write a 'C' functions to arrange the elements of an integer array in such a way that all the negative elements are before the positive elements. The array is passed to it as an arg

Calculate period of congestion in a particular exchange, In a particular ex...

In a particular exchange during busy hour 1200 calls were offered to a group of trunks, during this time 6 calls were lost. The average call duration being 3 minutes Calculate

Write a program to perform multiplication of two numbers, Q. Write a progr...

Q. Write a program to perform multiplication of two numbers in specified radix. Check that entered numbers are in specified radix or not else error message should be displayed.

What is view, What is View? A simple view can be thought of as a subset...

What is View? A simple view can be thought of as a subset of a table. It can be used for retrieving data, as well as updating or deleting rows. Rows updated or deleted in the v

What is compact disk rom, Q. What is Compact Disk ROM? Both audio CD an...

Q. What is Compact Disk ROM? Both audio CD and CD-ROM (compact disk read-only memory) share similar technology. Main difference is that CD-ROM players are more rugged and have

Direct mapped cache - computer architecture, Direct Mapping: In this p...

Direct Mapping: In this particular technique, block j of the primary memory maps onto block j modulo 128 of the cache. The primary memory blocks 0,128,256,...is loaded

Hashing collision resolution techniques, Hashing collision resolution techn...

Hashing collision resolution techniques are a) Chaining, b) Bucket addressing

Flat, nfa significance

nfa significance

Write Your Message!

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