Assembly Hello World!
Assembly Hello World!
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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. OneCompiler also has reference programs, where you can look for the sample programs and start learning. Happy learning!!
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.
Assembly language usually consists of three sections,
To initialize variables and constants, buffer size these values doesn't change at runtime.
To declare variables
_startspecifies the starting of this section where the actually code is written.
There are various define directives to allocate space for variables for both initialized and uninitialized data.
1. To allocate storage space to Initialized data
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
|RESB||Reserve a Byte|
|RESW||Reserve a Word|
|RESD||Reserve a Doubleword|
|RESQ||Reserve a Quadword|
|REST||Reserve a Ten Bytes|
Constants can be defined using
- To define numeric constants
CONSTANT_NAME EQU regular-exp or value
To define numeric constants.
%assign constant_name value
- To define numeric or string constants.
%define constant_name value
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.
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