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

Asp.net, how work for asp.net

how work for asp.net

Explain the compiler - computer programming, Explain the Compiler - Compute...

Explain the Compiler - Computer Programming? The Compiler is a program that translates source code into object code. The compiler derives its name from the means it works looki

Multidimensional arrays defined in terms of an array, How is multidimension...

How is multidimensional arrays defined in terms of an array of pointer? An element in a multidimensional array like two-dimensional array can be shown by pointer expression as

Write html code to accomplish the web page to insert frame, Write the HTML ...

Write the HTML code to accomplish the web page to insert the frame extending 300 pixels across the page from left side. The HTML code to accomplish the web page is given below

Are there any special rules about inlining, Are there any special rules abo...

Are there any special rules about inlining? Yes, there are some rules about inlining - a.) Any source files which used inline function should contain function's definition.

Algebra, Discrete Mathematics - (A?B)-(AnB)=(A-B)?(B-A) - prove by cases?? ...

Discrete Mathematics - (A?B)-(AnB)=(A-B)?(B-A) - prove by cases?? State which law you have used at each step. I''ve just started learning this, this semester .. and i havnt quite

The concept of process-parallel computing, The Concept of Process Infor...

The Concept of Process Informally, a method is a program in execution, behind the program has been loaded in the main memory. However, a method is more than just a program code

Explain register indirect addressing, Q. Explain Register Indirect Addressi...

Q. Explain Register Indirect Addressing? In this addressing technique the operand is data in memory pointed to by a register. Or we can say in other words that the operand fie

What are the limitations of a cyclotron, Q. What are the limitations of a c...

Q. What are the limitations of a cyclotron? Limitations (i) Maintaining a consistent magnetic field over a large area of the Dees is difficult. (ii) At high rapidity

I2c protocol bus , I²C TECHNOLOGIES The I2C protocol bus is two bi-dire...

I²C TECHNOLOGIES The I2C protocol bus is two bi-directional wires, serial data (SDA) and serial clock (SCL), that transmit information between the devices connected to the bus.

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