Hello,students in this article we learn about Addressing modes of 8086 microprocessor so read this article till end.
What is Adressing Mode?
Addressing modes are other ways by that C.P.U. will access data or operands. They confirm a way to access a particular memory address. To load any data from and to memory/registers, MOV instruction is used. The syntax of MOV instruction is:
MOV Destination, Source
It copies the information of 2nd operand (source) into the 1st operand (destination). To access memory, phase registers are used along side general registers.
The approach of specifying information to be operated by AN instruction is thought as addressing modes. This specifies that the given data is an on the spot data or an address. It conjointly specifies whether or not the given quantity is register or register pair.
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Addressing modes of 8086 types
1. Register mode – In this kind of addressing mode each the quantitys are registers.
MOV AX, BX XOR AX, DX ADD AL, BL
2. Immediate mode – In this type of addressing mode the supply operand could be a eight bit or sixteen bit data. Destination operand will ne’er be immediate data.
MOV AX, 2000 MOV CL, 0A ADD AL, 45 AND AX, 0000
Note that to initialize the worth of section register an register is required.
MOV AX, 2000 MOV CS, AX
3. Displacement or direct mode – In this type of addressing mode the effective address is directly given within the instruction as displacement.
MOV AX, [DISP] MOV AX, 
4. Register indirect mode – In this addressing mode the effective address is in SI, DI or BX.
MOV AX, [DI] ADD AL, [BX] MOV AX, [SI]
5. Based indexed mode – In this the effective address is add of base register and index register.
Base register: BX, BP Index register: SI, DI
The physical memory address is calculated consistent with the bottom register.
MOV AL, [BP+SI] MOV AX, [BX+DI]
6. Indexed mode – In this kind of addressing mode the effective address is add of register and displacement.
MOV AX, [SI+2000] MOV AL, [DI+3000]
7. Based mode – In this the effective address is that the sum of base register and displacement.
MOV AL, [BP+ 0100]
8. Based indexed displacement mode – In this type of addressing mode the effective address is the sum of index register, base register and displacement.
MOV AL, [SI+BP+2000]
9. String mode – This addressing mode is expounded to string instructions. during this the worth of SI and DI are motorcar incremented and decremented relying upon the value of directional flag.
MOVS B MOVS W
10. Input/Output mode – This addressing mode is related with input output operations.
IN A, 45 OUT A, 50
11. Relative mode –In this the effective address is calculated with respect to instruction pointer.
JNZ 8 bit address IP=IP+8 bit address
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