ELFIO/tests/elf_examples/asm.s

; nasm -f elf hello.asm		# this will produce hello.o ELF object file
; ld -s -o hello hello.o	# this will produce hello executable

section	.text
    global _start			;must be declared for linker (ld)

_start:					;tell linker entry point

	mov	edx,len	;message length
	mov	ecx,msg	;message to write
	mov	ebx,1	;file descriptor (stdout)
	mov	eax,4	;system call number (sys_write)
	int	0x80	;call kernel

	mov	eax,1	;system call number (sys_exit)
	int	0x80	;call kernel

section	.data

msg	db	'Hello, world!',0xa	;our dear string
len	equ	$ - msg			;length of our dear string