Addressing Mode: Arithmetic Group Instruction

Arithmetic Group Instruction:     The 8085 microprocessor performs various arithmetic operations such as addition, subtraction, increment and decrement. These arithmetic operations have the following mnemonics.

Data transfer group

Data transfer group: These instruction which are used to transfer a data from one register to another or register to memory or vice versa. E.g. MOV, MVI, LDA etc.

Addressing Modes:-

          Each instruction requires certain data in which it has to operate. There are various technique to specify data for instruction. These technique are called addressing mode.

            The 8085 consists of 5 different addressing modes. They are:

1.     Direct Address Mode:     In this mode of addressing, the address of the operand is given in the instruction itself. E.g. STA 2000H, IN 02H.         

2.     Immediate Addressing Mode: In this addressing mode, the operand is specified within the instruction itself. E.g. MVI A, 20H and LXI H, 2500H.

3.     Register Addressing Mode:      The operands are in general purpose register. The op-code specifies the address of the registers in addition to the operation to be performed. E.g. MOV A, B and ADD B.

4.     Register Indirect Addressing Mode:  In this mode of addressing, the address of operand is specified by the register pair as a pointer of operand. E.g. LXI M, 2000H and MOV A, M.

5.     Implied Addressing Mode:        These are certain instruction which operate on the content of an accumulator, such instruction do not require the address of operand. E.g. CMA, RAR, HLT etc.