1. Introduction

There are many ways to locate data and instructions in memory and these methods are called 'memory address modes'

Memory address modes determine the method used within the program to access data either from within the CPU or external RAM. Some memory addressing modes can control program flow.

The five memory address modes are

• Direct
• Indirect
• Immediate
• Indexed
• Relative

It should be noted that high level languages also make use of these memory address modes, but the compiler hides away all the details from the programmer.

On the other hand if you are coding using a low level assembly language, you will make direct use of these modes.

Each memory mode has its advantages and disadvantages and the programmer needs to understand which one should be used at any point within his code.