Instruction Set Of 8086 Microprocessor & Data Movement Instruction

Instruction Set Of 8086 Microprocessor

The instruction set of 8086 microprocessor contains different instruction to perform operations such as data transfer, arithmetic, logic, shift, rotate, & control.

An instruction for microprocessor is the way to specify operations that we perform upon data. Data is stored in operands. For 8086 microprocessor an operands can be 16-bit internal register, a memory location or immediate number. Most of 8086 instructions have two operands (source and destination) but many instructions have only one operand. The instructions of 8086 classified into following groups.

1] Data Movement Instruction

2] Arithmetic

3] Logical

4] Shift & Rotate

5] Branching & Jump

6] Machine control or Miscellaneous instruction.

I] Data Movement Instruction

The instructions in this group are used to copy data from source operand to destination operand.

1] MOV

Syntax –

This instruction is used to copy data stored in source into destination. The source can be 8/16 bit register, memory location or immediate data (number) . Destination can be 8/16 bit register, memory location.

Example, MOV AL,04H

MOV AL,BL

MOV AH,[2000]

MOV [4000],AX

MOV [5000],35H

2] XCHG

Syntax –

This instruction is used to exchanges the contents of source with the contents of destination. The source can be 8/16 bit register or memory location. Destination can be 8/16 bit register, memory location. The XCHG cannot directly exchange the contents of two memory location

Example, XCHG AL, BL

XCHG CX, DX

1) Program Title:- WALP (Write Assembly Language Program) to copy 8 bit number i.e. 22H & 55 H in AL & BL register respectively.

Data: - 22 H & 55 H

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AL,22H	COPY 22H IN AL
			MOV	BL,55H	COPY 55H IN BL
			INT	03	STOP

Result:-

AL = 22H

BL = 55H

2) Program Title: - WALP (Write Assembly Language Program) to store 55 H, 88 H, 99 H, 44 H, 02 H, 03 H, 04 H & 05H IN AL, BL, CL, DL, AH, BH, CH & DH Register respectively.

Data: -55 H, 88 H, 99 H, 44 H, 02 H, 03 H, 04 H & 05H

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AL,55H	COPY 55H IN AL
			MOV	BL,88H	COPY 88H IN BL
			MOV	CL,99H	COPY 99H IN CL
			MOV	DL, 44H	COPY 44H IN DL
			MOV	AH,02H	COPY 02H IN AH
			MOV	BH,03H	COPY 03H IN BH
			MOV	CH,04H	COPY 04H IN CH
			MOV	DH,05H	COPY 05H IN DH
			INT	03	STOP

Result:-

AX = 0255H

BX = 0388H

CX = 0499H

DX = 0544H

3) Program Title: - WALP to store 55 H, 88 H, in AL, BL Register respectively. Copy the contents of AL register on memory location [2000] and contents of BL register on memory location [3000]. (DS = 0200H)

Data: -55 H, 88 H, [2000] & [3000]

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AX,0200H	Initialisation of DS
			MOV	DS,AX	Initialisation of DS
			MOV	AL,55H	Copy 55h In AL
			MOV	BL,88H	Copy 88h In BL
			MOV	[2000],AL	Copy Contents Of Al On Memory Location [2000]
			MOV	[3000],BL	Copy Contents Of Al On Memory Location [3000]
			INT	03	STOP

Result:-

DS : OFFEST : DATA

0200:[2000]:55H

0200:[3000] :88H

4) Program Title: - WALP to store 55 H, 88 H, in AL, BL Register respectively. Exchange contents of AL&BL using third register.

Data: - 55 H& 88 H

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AL,22H	COPY 22H IN AL
			MOV	BL,55H	COPY 55H IN BL
			MOV	CL,AL	COPY THE CONTENTS OF AL TO CL
			MOV	AL,BL	COPY THE CONTENTS OF BL TO AL
			MOV	BL,CL	COPY THE CONTENTS OF CL TO BL
			INT	03	STOP

AL = 55H

BL = 22H

5) Program Title: - WALP to store 55 H, 88 H, in AL, BL Register respectively. Copy the contents of AL register on memory location [2000] and contents of BL register on memory location [3000] then exchange contents of memory location [2000] & [3000] using register. (DS = 0200H)

Data: - 55 H, 88 H, [2000] & [3000]

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AX,0200H	Initialisation of DS
			MOV	DS,AX	Initialisation of DS
			MOV	AL,55H	Copy 55H In AL
			MOV	BL,88H	Copy 88H In BL
			MOV	[2000],AL	Copy Contents Of AL On Memory Location [2000]
			MOV	[3000],BL	Copy Contents Of AL On Memory Location [3000]
			MOV	CL,[2000]	Copy Contents Of Memory Location [2000] to CL
			MOV	DL,[3000]	Copy Contents Of Memory Location [3000] to DL
			MOV	[2000],DL	Copy Contents Of DL On Memory Location [2000]
			MOV	[3000],CL	Copy Contents Of CL On Memory Location [3000]
			INT	03	Stop

Result:-

DS : OFFEST : DATA

0200:[2000]:88H

0200:[3000] :55H

6) Program Title: - WALP to store 44H & 55H in AL & BL register respectively. Exchange the contents of register using XCHG instruction.

Data: - 44H & 55H

Address	Op-code	Label	Mnemonic	Operand	Comments
			MOV	AL,44H	COPY 44H IN AL
			MOV	BL,55H	COPY 55H IN BL
			XCHG	AL,BL	Exchange contents of AL register With BL register
			INT	03	STOP

Result:-

AL = 55H

BL = 44H

3) PUSH

Syntax – PUSH Source

This instruction is used to copy data stored in source onto memory location pointed by stack pointer register(SP). The source can be 16 bit register. Therefore after execution of PUSH instruction SP is decremented by 2. This instruction copies data into stack memory area pointed by stack pointer.

Example, PUSH AX

PUSH IP

PUSH FLAG

4) POP

Syntax – POP Destination

This instruction is used to copy data from memory location pointed by stack pointer register (SP) into destination. The destination can be 16 bit register. Therefore after execution of POP instruction SP is incremented by 2. This instruction copies data from stack memory area pointed by stack pointer.

Example, POP AX

POP CS

POP FLAG

Operation code : The operation code field in the instruction specifies the operation to be performed.

Instruction Set Of 8086 Microprocessor & Data Movement Instruction