Addressing Modes in 8085

The way in which the operand of an instruction is specified is referred to as addressing modes. The addressing mode specifies how the address field of the instruction is to be interpreted before the operand is actually executed.

The 8085 microprocessor has 5 types of addressing modes.

Immediate Addressing Mode

In immediate addressing mode, the source operand is always data.

Example: MVI B 37H (Copy 37H immediately into register B)

Direct Addressing Mode

In direct addressing mode, the memory location where the data to be operated is directly specified as the operand.

Example: LDA 2030 (Load operand in memory location 2030 to Accumulator)

Register Addressing Mode

In register addressing mode, the register in which the data to be operated is directly specified as the operand.

Example: MOV B (Copies data in register B into Accumulator)

Register Indirect Mode

In register indirect addressing mode, the memory location where the data to be operated is indirectly specified by a register pair.

Example: MOV A, M (Move the contents of the memory location pointed by the H-L pair to the Accumulator)

Implied/Implicit Addressing Mode

In implied/ implicit addressing mode, the operand is hidden and the data to be operated is available implicitly in the instruction.

Example: CMA (Complement Accumulator)

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