Hello world in x86-64 assembly

.gitignore

*.o

hello.s

.text
.globl _start

_start:
    # Print greeting
    movq $1, %rax               # sys_write
    movq $1, %rdi               # stdout
    movq $hello, %rsi           # address of string
    movq $hello_length, %rdx    # length of string
    syscall

    # Exit
    movq $60, %rax              # sys_exit
    movq $0, %rdi               # return value
    syscall


.section .rodata
hello:
    .string "Hello World!\n"
hello_length = . - hello

Makefile

hello:
	as -o hello.o hello.s
	ld -o hello hello.o