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

Registered ports, A) What does this file have? Where was the information in...

A) What does this file have? Where was the information in this file acquired from? What is the information in this file used for? B)  What is the range for popular ports? What i

C programming, At a shop of marbles, packs of marbles are prepared. Packets...

At a shop of marbles, packs of marbles are prepared. Packets are named A, B, C, D, E …….. All packets are kept in a VERTICAL SHELF in random order. Any numbers of packets with thes

Calculate max distance so subscriber get speech reproduction, In a subscrib...

In a subscriber loop that contains a series resistance of 300 ohms to protect the batteries in the exchange, a normalized telephone draws 10 mA and its standard input d.c. resistan

What are the disadvantages of a vpn implementation, What are the Disadvanta...

What are the Disadvantages of a VPN implementation The greatest disadvantage of a VPN implementation is its non-flexibility to accept unknown locations. VPN works extremely wel

Describe about the digital cameras, Describe about the Digital cameras ...

Describe about the Digital cameras The microprocessor would be used to control the below functions, for instance: - shutter speed - lens focus - Flash - Aperture (l

Virtual memory and organization of a cache memory, Described virtual memory...

Described virtual memory Ans: Data is to be stored in physical memory locations that have addresses different from those that specified by the program. The memory control circu

Add multiple layout cells, Q. Add Multiple Layout Cells ? Next you will...

Q. Add Multiple Layout Cells ? Next you will add three layout cells below the logo cell you just created. Afterwards you will insert page's navigation buttons in these cells.

Define deadlock, Define deadlock. A process requests resources; if the ...

Define deadlock. A process requests resources; if the resources are not available at that time, the method enters a wait state. Waiting processes might never again change state

Cluster computing, The concept of clustering is definite as the use of mult...

The concept of clustering is definite as the use of multiple computers, typically PCs or multiple storage devices, UNIX workstations, and their interconnections, to form what appea

Embedded system design using c, W To date we have discussed elementary high...

W To date we have discussed elementary high level language programming and low level assembler programming, one of the benefits of C is the integration of both , this requires a re

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