What is mean by addressing mode? Explain all the addressing mode available in 8085 microprocessor.

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Suresh Chand · Accepted Answer

The different ways in which a source operand is denoted in an instruction is known as addressing modes. In 8085 microprocessor there are 5 types of addressing modes: 1. Immediate Addressing Mode – In immediate addressing mode the source operand is always data. If the data is 8-bit, then the instruction will be of 2 bytes, if the data is of 16-bit then the instruction will be of 3 bytes. Examples: MVI B 45 (move the data 45H immediately to register B) LXI H 3050 (load the H-L pair with the operand 3050H immediately) JMP address (jump to the operand address immediately) 2. Register Addressing Mode – In register addressing mode, the data to be operated is available inside the register(s) and register(s) is(are) operands. Therefore the operation is performed within various registers of the microprocessor. Examples: MOV A, B (move the contents of register B to register A) ADD B (add contents of registers A and B and store the result in register A) INR A (increment the contents of register A by one) 3. Direct Addressing Mode – In direct addressing mode, the data to be operated is available inside a memory location and that memory location is directly specified as an operand. The operand is directly available in the instruction itself. Examples: LDA 2050 (load the contents of memory location into accumulator A) LHLD address (load contents of 16-bit memory location into H-L register pair) IN 35 (read the data from port whose address is 35) 4. Register Indirect Addressing Mode – In register indirect addressing mode, the data to be operated is available inside a memory location and that memory location is indirectly specified by a register pair. Examples: MOV A, M (move the contents of the memory location pointed by the H-L pair to the accumulator) LDAX B (move contents of B-C register to the accumulator) LXIH 9570 (load immediate the H-L pair with the address of the location 9570) 5. Implied/Implicit Addressing Mode – In implied/implicit addressing mode the operand is hidden and the data to be operated is available in the instruction itself. Examples: CMA (finds and stores the 1’s complement of the contents of accumulator A in A) RRC (rotate accumulator A right by one bit) RLC (rotate accumulator A left by one bit)

What is mean by addressing mode? Explain all the addressing mode available in 8085 microprocessor.

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What is mean by addressing mode? Explain all the addressing mode available in 8085 microprocessor.

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