Every instruction of a program has to operate on data. The method of specifying the data to be operated by the instruction is called Addressing. The 8085 supports the following five addressing modes:
1. Immediate Addressing
2. Direct Addressing
3. Register Addressing
4. Register Indirect Addressing
5. Implied Addressing
In immediate addressing mode, the data is specified in the instruction itself. The data will be a part of the program instruction.
In direct addressing mode, the address of the data is specified in the instruction. The data will be in memory. In this addressing mode, the program instructions and data can be stored in different memory blocks.
In register addressing mode, the instruction specifies the name of the register in which the data is available.
Register Indirect Addressing:
In register indirect addressing mode, the instruction specifies the name of the register in which the address of the data is available. Here the data will be in memory and the address will be in a registered pair.
In implied addressing mode, the instruction itself specifies the data to be operated.