NASM Ubuntu install and simple to use tutorial

1. Install

sudo apt-get install nasm

Such nasm installed on the Terminal enter the command:

nasm -version

Output version information on the installation is successful

2. Use

Create a "hello.asm" file:

touch hello.asm
gedit hello.asm

Enter the following assembly code in the file

section .data
  hello:     db 'Hello world!',10    ; 'Hello world!' plus a linefeed character
  helloLen:  equ $-hello             ; Length of the 'Hello world!' string
                                     ; (I'll explain soon)
 
section .text
  global _start
 
_start:
  mov eax,4            ; The system call for write (sys_write)
  mov ebx,1            ; File descriptor 1 - standard output
  mov ecx,hello        ; Put the offset of hello in ecx
  mov edx,helloLen     ; helloLen is a constant, so we don't need to say
                       ;  mov edx,[helloLen] to get it's actual value
  int 80h              ; Call the kernel
 
  mov eax,1            ; The system call for exit (sys_exit)
  mov ebx,0            ; Exit with return code of 0 (no error)
  int 80h

Save and exit.
Compile

nasm -f elf64 hello.asm

If you put a 32-bit system elf64instead elf32
link

ld -s -o hello hello.o

run

./hello

Terminal output "Hello, world!" No problem