What is meant by ‘addressing mode’ in a Microprocessor ?

Every instruction which indicates an operation to be performed on certain data inside a Microprocessor. Now The methods to specify the data for the instructions, known as ‘addressing modes’. Remember The Execution Unit ( EU ) of a Microprocessor can access all resistor and Data which is store in Resistor or Immediate operands. The EU dose not have direct access over a Memory Location so some methods is needed to access those Data this is known as Addressing Modes

For 8085 microprocessor, there are mainly five addressing modes. These are:

•  Direct addressing
•  Register addressing
•  Register indirect addressing
•  Immediate addressing
•  Implicit addressing.

     Direct Addressing: In this mode, the operand is specified within the instruction itself that means in instruction we can find that from/to where data is being access because address is given in Operand. Examples of this type are:
LDA 4000H, STA 5513H, etc.

    Register Addressing: In this mode of addressing, the operand are in the general purpose registers and data operation done between the register.
Examples are: MOV A, B ; ADD D, etc.

    Register Indirect Addressing: MOV A, M; ADD M are examples of this mode of addressing. These instructions utilise 1-byte. In this mode, instead of specifying a register, a register pair is specified to accommodate the 16-bit address of the operand.

   Immediate Addressing: MVI A, 07; ADI 0F are examples of Immediate Addressing mode. The operand is specified in the instruction in this mode. Here, the operand address is not specified But directly work with DATA.

 Implicit Addressing: In this mode of addressing, the operand is fully absent. Examples are RAR, RAL, CMA, etc.