helloWorld.s

; X86_64 Assembly Language Hello World

global    _start
section   .text

_start:    
    mov       rax, 1         ; system call for write
    mov       rdi, 1                  ; file handle 1 is stdout
    mov       rsi, _message           ; address of string to output
    mov       rdx, 13                 ; number of bytes
    syscall                           ; invoke operating system to do the write
    mov       rax, 60         ; system call for exit
    xor       rdi, rdi                ; exit code 0
    syscall                           ; invoke operating system to exi

section   .data

_message:  
    db        "Hello, World", 10      ; note the newline at the end