Assembly language Programming Codes for the 8086 Microprocessor

Assembly language is a low-level programming language that is used to write software that can be executed directly by a computer's central processing unit (CPU). It is particularly useful for programming microprocessors, such as the 8086 microprocessor.

In order to write effective assembly language programs for the 8086 microprocessor, it is essential to have a deep understanding of the internal structure of the processor itself. This knowledge allows you to write code that makes efficient use of the processor's capabilities and can be optimized for speed and performance.

Fortunately, there are a variety of resources available to help you learn assembly language programming for the 8086 microprocessor. One useful starting point is the Microsoft Macro Assembler (MASM), which is a popular assembler used for programming on the x86 architecture.

To help you get started with MASM, we've provided some sample codes below that you can use for practice:

Code-1: Print a message 'hello world'

.MODEL SMALL
.STACK 100H

.DATA
MSG DB 'HELLO WORLD!$'

.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG
MOV AH,9
INT 21H

MOV AH,4CH
INT 21H


MAIN ENDP
END MAIN 
...................................................

Code-2: Print all the ASCII symbols from 0 to 256

.MODEL SMALL
.STACK 100H

.CODE
MAIN PROC

MOV AH,2
MOV CX,256
MOV DL,0

PRINT_LOOP:
INT 21H
INC DL
DEC CX
JNZ PRINT_LOOP 


MOV AH,4CH
INT 21H 


MAIN ENDP
END MAIN 
.................................................

Code-3: Convert a lowercase letter into uppercase

.MODEL SMALL
.STACK 100H
.DATA
MSG1 DB 'ENTER THE LOWERCASE LATTER:$'
MSG2 DB 'CORRESPONDING UPPERCASE LATTER IS:'
CHAR DB ? , '$'
.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
MOV AH,9
INT 21H

MOV AH,1
INT 21H

SUB AL,20H 
MOV CHAR,AL

LEA DX,MSG2
MOV AH,9
INT 21H

MOV AH,4CH
INT 21H 


MAIN ENDP
END MAIN 
......................................................

Code-4: Convert an uppercase letter into lowercase 

.MODEL SMALL
.STACK 100H
.DATA
MSG1 DB 'ENTER THE UPPERCASE LATTER:$'
MSG2 DB 'CORRESPONDING LOWERCASE LATTER IS:'
CHAR DB ? , '$'
.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
MOV AH,9
INT 21H

MOV AH,1
INT 21H

ADD AL,20H 
MOV CHAR,AL

LEA DX,MSG2
MOV AH,9
INT 21H

MOV AH,4CH
INT 21H 


MAIN ENDP
END MAIN 
......................................................

Code-5: Addition of two numbers

.MODEL SMALL
.STACK 100H

.DATA 
MSG1 DB 10,13,'ENTER YOUR FIRST NUMBER:$'
MSG2 DB 10,13,'ENTER YOUR SECOND NUMBER:$'
MSG3 DB 10,13,'ADD=$'
N1 DB ?
N2 DB ?
RE DB ?

.CODE 
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
MOV AH,9
INT 21H

MOV AH,1
INT 21H

SUB AL,30H
MOV N1,AL

LEA DX,MSG2
MOV AH,9
INT 21H

MOV AH,1
INT 21H

SUB AL,30H
MOV N2,AL

MOV AL,N1
ADD AL,N2
MOV RE,AL

ADD AH,30H
ADD AL,30H
MOV BX,AX

LEA DX,MSG3
MOV AH,9
INT 21H

MOV AH,2
MOV DL,BH
INT 21H
MOV AH,2 
MOV DL,BL
INT 21H

MOV AH,4CH
INT 21H

MAIN ENDP
END MAIN
........................................................

Code-6: Multiplication of two numbers

.MODEL SMALL
.STACK 100H
.DATA
NUM1 DB ?
NUM2 DB ? 
RESULT DB ?
MSG1 DB 10,13,'ENTER FIRST NUMBER: $' 
MSG2 DB 10,13,'ENTER SECOND NUMBER: $' 
MSG3 DB 10,13,'AFTER MULTIPLYCATION RESULT IS: $' 
.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
MOV AH,9
INT 21H

MOV AH,1
INT 21H
SUB AL,30H
MOV NUM1,AL

LEA DX,MSG2
MOV AH,9
INT 21H

MOV AH,1
INT 21H
SUB AL,30H
MOV NUM2,AL

MUL NUM1

MOV RESULT,AL
AAM

ADD AH,30H
ADD AL,30H

MOV BX,AX

LEA DX,MSG3
MOV AH,9
INT 21H

MOV AH,2
MOV DL,BH
INT 21H 

MOV AH,2
MOV DL,BL
INT 21H

MOV AH,4CH
INT 21H 

MAIN ENDP
END MAIN 
.....................................................

Code-7: Taking input a string

.MODEL SMALL
.STACK 100H
.DATA
STRING DB ?
EXT DB '$'
MSG DB 10,13,'ENTER STRING $' 
.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG
MOV AH,9
INT 21H

LEA SI,STRING

INP:
MOV AH,1
INT 21H
MOV [SI],AL
INC SI

CMP AL,0DH
JNZ INP

MOV [SI],'$'
LEA DX,STRING
MOV AH,9
INT 21H 

MOV AH,4CH
INT 21H 

MAIN ENDP
END MAIN 
......................................................

Code-8: Reverse a string

.MODEL SMALL
.STACK 100H 
.CODE
MAIN PROC

MOV AH,2
MOV DL,'?'
INT 21H

XOR CX,CX
MOV AH,1
INT 21H

WHILE_:
CMP AL,0DH
JE END_WHILE

PUSH AX
INC CX

INT 21H
JMP WHILE_

END_WHILE:
MOV AH,2
MOV DL,0DH
INT 21H
MOV DL,0AH
INT 21H
JCXZ EXIT

TOP:
POP DX
INT 21H
LOOP TOP
EXIT: 
MOV AH,4CH
INT 21H 

MAIN ENDP
END MAIN
...................................................

Code-9: Determine prime number

.MODEL SMALL
.STACK 100H
.DATA
NUM DB ?
MSG1 DB 10,13,'ENTER NO: $' 
MSG2 DB 10,13,'NOT PRIME: $' 
MSG3 DB 10,13,'PRIME $' 
.CODE
MAIN PROC

MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
MOV AH,9
INT 21H

MOV AH,1
INT 21H
SUB AL,30H
MOV NUM,AL

CMP AL,1
JLE LBL2
MOV AH,00
CMP AL,3
JLE LBL3
MOV AH,00

MOV CL,2
DIV CL
MOV CL,AL

LBL1:
MOV AH,00
MOV AL,NUM
DIV CL
CMP AH,00
JZ LBL2
DEC CL
CMP CL,1
JNE LBL1
JMP LBL3
LBL2:
MOV AH,9
LEA DX,MSG2
INT 21H
JMP EXIT
LBL3:
MOV AH,9
LEA DX,MSG3
INT 21H
EXIT:
MOV AH,4CH
INT 21H 

MAIN ENDP
END MAIN 

By studying and practicing with examples such as these, you can develop a strong foundation in assembly language programming and become proficient in programming the 8086 microprocessor. Good luck!

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