 .model small
.data
menu db 10d, 13d,"MENU"
db 10d,"1.Enter the string"
db 10d,"2.Calculate length of the string"
db 10d,"3.Reverse string"
db 10d,"4.Check palindrome"
db 10d,"5.Exit"
db 10d,"Enter your choice:$"

m1 db 10d,"Enter string:$"
m2 db 10d,"Length of string:$"
m3 db 10d,"Reversed string:$"
m4 db 10d,"string is palindrome"
m5 db 10d,"Exit"

string db 15dup('$')
string2 db 15dup('$')
len db 0000h
;*************MACRO**************
print macro xx
le dx,xx
mov ah,09h
int 21h
endm
.code
mov ax,@data
mov ds,ax
main
print menu 
mov ah.01h
int 21h

cmp al,'5'
jae Exit
cmp al,'1'
je case1
cmp al,'2'
je case2
cmp al,'3'
je case3
cmp al,'4'
je case4

;***********CASES*****************
exit:
mov ah,4ch
int 21h
case1:
print m1
lea si,string
loop1:
mov ah,01h
int 21h
cmp al,0Dh
je skip1
mov [si],al
inc si
inc len
jmp loop1
skip1:
mov al,24h
mov bytes[si],al
jmp main

case2:
print m2
mov dl [len]
add dl,30h
cmp dl,39h
jbe skip2
add dl,07h

skip2:
mov ah,02h
int 21h
jmp main

case3:
call stringreverse
print m3
print string2
jmp main

case4:
lea si,string
lea di,string2
mov cl,[len]

loop3:
mov al,[si]
mov bl,[di]
inc si
inc di
cmp al,bl
jne skip3
loop loop3
print m4
jmp main

skip3
print m5
jmp main

;******PROCEDURE***********
stringreverse proc
lea si,string
lea di,string2

mov cl,[len]
mov ch,00
add di,cx
dec di

loop2:
mov al,[si]
mov [di],al
inc si
dec di
loop loop2 
ret
endp
end

created 3 years ago

Assembly Online Compiler

Write, Run & Share Assembly code online using OneCompiler's Assembly online compiler for free. It's one of the robust, feature-rich online compilers for Assembly language. Getting started with the OneCompiler's Assembly compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as Assembly and start coding.

About Assembly

Assembly language(asm) is a low-level programming language, where the language instructions will be more similar to machine code instructions.

Every assembler may have it's own assembly language designed for a specific computers or an operating system.

Assembly language requires less execution time and memory. It is more helful for direct hardware manipulation, real-time critical applications. It is used in device drivers, low-level embedded systems etc.

Syntax help

Assembly language usually consists of three sections,

Data section

To initialize variables and constants, buffer size these values doesn't change at runtime.
bss section

To declare variables
text section

_start specifies the starting of this section where the actually code is written.

Variables

There are various define directives to allocate space for variables for both initialized and uninitialized data.

1. To allocate storage space to Initialized data

Syntax

variable-name    define-directive    initial-value

Define Directive	Description	Allocated Space
DB	Define Byte	1 byte
DW	Define Word	2 bytes
DD	Define Doubleword	4 bytes
DQ	Define Quadword	8 bytes
DT	Define Ten Bytes	10 bytes

2. To allocate storage space to un-initialized data

Define Directive	Description
RESB	Reserve a Byte
RESW	Reserve a Word
RESD	Reserve a Doubleword
RESQ	Reserve a Quadword
REST	Reserve a Ten Bytes

Constants

Constants can be defined using

1. equ

To define numeric constants

CONSTANT_NAME EQU regular-exp or value

2. %assign

To define numeric constants.

%assign constant_name value

3. %define

To define numeric or string constants.

%define constant_name value

Loops

Loops are used to iterate a set of statements for a specific number of times.

mov ECX,n
L1:
;<loop body>
loop L1

where n specifies the no of times loops should iterate.

Procedures

Procedure is a sub-routine which contains set of statements. Usually procedures are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

procedure_name:
   ;procedure body
   ret