section .data
prompt db "Enter the number of integers: ", 0
input_prompt db "Integer %d: ", 0
sum_msg db "Sum: %d", 0
section .bss
array resd 100 ; Array to store integers
numElements resd 1 ; Variable to store the number of elements entered by the user
section .text
global _start
_start:
; Prompt user for number of integers
mov eax, 4
mov ebx, 1
mov ecx, prompt
mov edx, 27
int 0x80
; Read number of integers from user input
mov eax, 3
mov ebx, 0
lea ecx, [numElements]
mov edx, 4 ; Size of a 32-bit integer
int 0x80
; Input loop
input_loop:
; Prompt user for each integer and store in array
mov eax, numElements
mov ebx, eax ; Use as loop counter
lea ecx, [input_prompt]
mov edx, dword [ebx*4 + array]
push ebx ; Save loop counter on stack
push ecx ; Save input prompt message on stack
push edx ; Save address of current element on stack
mov eax, 4
mov ebx, 1
pop ecx
pop edx
pop ebx
int 0x80
; Read integer from user input
mov eax, 3
mov ebx, 0
pop ecx
pop edx
pop ebx
int 0x80
; Store input in array
mov ebx, eax ; Use as loop counter
mov dword [ebx*4 + array], edx ; Store input at array[ebx]
dec eax ; Decrement loop counter
jnz input_loop
; Calculate sum of array elements
xor eax, eax ; Initialize sum to zero
mov ebx, numElements ; Number of elements entered by user
sum_loop:
add eax, dword [ebx*4 + array] ; Add current element to sum
dec ebx ; Decrement loop counter
jnz sum_loop
; Display the sum on the screen
push eax ; Save sum on stack
lea ecx, [sum_msg] ; Print sum message
mov edx, 10 ; Length of sum message
mov ebx, 1 ; File descriptor (stdout)
mov eax, 4 ; System call number (write)
int 0x80
; Exit
mov eax, 1
int 0x80
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.
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,
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.
There are various define directives to allocate space for variables for both initialized and uninitialized 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 |
| 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 can be defined using
CONSTANT_NAME EQU regular-exp or value
%assign constant_name value
%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