Addressing Mode

 What is addressing mode?

Addressing Mode is a way to show the location of a required object/operant in the computer. The Addressing mode specifies a rule for where the operant is present in Memory and how we can access this operation from memory Address .the output of an Addressing Mode is an Effective Address

object:-object may be data or instruction

Effective Address:-Effective Address is an actual address of an object or where the actual operant  is present

Addressing Mode is implemented instruction in two ways

(1) Implicit 

(2) Explicit

Advantage of Addressing Mode 

(1) To give programmers facilities such  as Pointer, Counters for Loop Control, indexing

of data and program relocation

(2) To reduce the number of bits in the addressing field of the instruction.

Types of Addressing Mode

1.Implied Mode

2.Immediate Mode

3.Register Mode

4.Register Indirect Mode

5.Auto-Increment Mode 

6.Auto Decrement Mode

7.Direct Address Mode

8.Indirect Address Mode

9.Relative Address Mode

10. Base Register Mode

The Short trick to remember this addressing Mode

IIRRAAIDRBI

Different Symbols are used in the user program to refer to the different address mode

(1) #/I: Immediate Address Mode

(2) Regester Name:  Register Address Mode

(3) [ ] : Direct Address Mode

(4) @/( ): Indirect Address Mode

(5) Index Register Name: Index Address Mode

(6) +/- :Auto Indexed Address Mode