Addressing Modes of 8085 Microprocessor

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Addressing Modes of 8085 Microprocessor

Published by: Nuru

Published date: 18 Jun 2021

Addressing Modes of 8085 Microprocessor Photo

Addressing Modes of 8085

The way of specifying data to be operated by an instruction is known as addressing modes. This specifies that the given data is immediate data or an address. In this type of addressing mode the source operand is an 8 bit or 16-bit data. The destination operand can never be immediate data. These can be guided by addressing modes. Addressing modes in 8085 can be classified into 5 groups −

  • Immediate addressing mode
  • Register addressing mode
  • Direct addressing mode
  • Indirect addressing mode
  • Implied addressing mode

Immediate addressing mode
In this mode, the operand is specified in the instruction itself. An immediate mode instruction has an operand field rather than the address field.

Register addressing mode
In this mode, the operand is stored in the register and this register is present in the CPU. The instruction has the address of the Register where the operand is stored.

Direct Addressing Mode
In this mode, an effective address of the operand is present in the instruction itself.

  • Single memory reference to access data.
  • No additional calculations to find the effective address of the operand.

Indirect Addressing Mode
In this, the address field of instruction gives the address where the effective address is stored in memory. This slows down the execution, as this includes multiple memory lookups to find the operand.

Implied addressing mode                                                                                                                                           

Implied addressing is an addressing mode that does not require the specification of any additional information. Instructions that are used with implied addressing can not be followed by any information like an address or a constant. This omission of any addressing information at all is also called implied addressing.