Addressing modes are techniques used in computer architecture to specify the method for calculating the effective address of an operand.
Thank you for reading this post, don't forget to subscribe!• The effective address is the location in memory that holds the operand.
• Different addressing modes provide flexibility in accessing operands, optimizing code, and utilizing memory efficiently.
• The Intel 8085 microprocessor supports various addressing modes, which define how operands are specified in instructions.
Here are the addressing modes supported by the Intel 8085:
- Immediate Addressing Mode:
- Operand: Immediate data
- Example:
MVI A, 05H(Load immediate data 05H into register A)
- Register Addressing Mode:
- Operand: Register contents
- Example:
MOV B, C(Copy contents of register C to register B)
- Direct Addressing Mode:
- Operand: Memory address
- Example:
MOV A, M(Copy contents of memory location addressed by HL pair to register A)
- Register Indirect Addressing Mode:
- Operand: Register pair contents (HL, DE, BC)
- Example:
MOV A, M(Copy contents of memory location addressed by HL pair to register A)
- Immediate Addressing Mode (for 16-bit operations):
- Operand: Immediate data (16-bit)
- Example:
LXI H, 2030H(Load immediate 16-bit data into register pair HL)
- Relative Addressing Mode:
- Operand: 8-bit signed offset
- Example:
JC Label(Jump to the specified label if the carry flag is set)
- Indexed Addressing Mode:
- Operand: Index register (IX or IY) + Displacement
- Example:
MOV A, (IX+10)(Copy contents of the memory location at IX + 10 to register A)
- Direct Offset Addressing Mode:
- Operand: Memory address + 8-bit signed offset
- Example:
MOV A, 2050H + 10(Copy contents of the memory location at 2060H to register A)