 section .data
	hello:     db 'Hello world!',10    ; 'Hello world!' plus a linefeed character
	helloLen:  equ $-hello             ; Length of the 'Hello world!' string

section .text
	global _start

_start:
	mov         word ptr [bp-2],3323h
  mov         word ptr [bp-4],4343h
  mov         ax,word ptr [bp-2]
  add         ax,213h
  mov         word ptr [bp-6],ax
  mov         bx,word ptr [bp-4]
  sub         bx,0C15h
  mov         word ptr [bp-8],bx
  mov         cx,word ptr [bp-6]
  xor         cx,505h
  mov         word ptr [bp-0Ah],cx
  mov         dx,word ptr [bp-8]
  not         dx
  add         dx,5763h
  mov         word ptr [bp-0Ch],dx
  mov         ax,word ptr [bp-0Ah]
  shl         ax,1
  sub         ax,2F36h
  mov         word ptr [bp-0Eh],ax
  mov         bx,word ptr [bp-0Ch]
  shr         bx,1
  xor         bx,553Ah
  mov         word ptr [bp-10h],bx
  mov         cx,word ptr [bp-0Eh]
  or          cx,1234h
  add         cx,4
  mov         word ptr [bp-12h],cx
  mov         dx,word ptr [bp-10h]
  and         dx,4321h
  sub         dx,0AF2h
  mov         word ptr [bp-14h],dx
  mov         ax,word ptr [bp-12h]
  neg         ax
  xor         ax,0F9F8h
  mov         word ptr [bp-16h],ax
  mov         bx,word ptr [bp-14h]
  inc         bx
  add         bx,0EA01h
  mov         word ptr [bp-18h],bx
  mov         cx,word ptr [bp-16h]
  dec         cx
  sub         cx,0FFE1h
  mov         word ptr [bp-1Ah],cx

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