Hello world in assembly!

gistfile1.txt

# ----------------------------------------------------------------------------------------
# helloworld.s. Hello world in assembly!
# ----------------------------------------------------------------------------------------

     .global _start

    .text
_start:
# write(1, message, 13)
    mov     $1, %rax                # system call ID. 1 is write
    mov     $1, %rdi                # file handle 1 is stdout
    mov     $message, %rsi          # address of string to output
    mov     $13, %rdx               # string length
    syscall                         # system call invocation!

# exit(0)
    mov     $60, %rax               # system call ID. 60 is exit
    xor     %rdi, %rdi              # we want return code 0
    syscall                         # system call invocation!
message:
    .ascii  "Hello, world\n"