r2

syscall_x86

syscall_x86.s

        .file   "syscall_x86.s"
        .intel_syntax noprefix
        .section .rodata

.LC0:
        msg: .string  "Hello, world!\n"
        .text
        .globl  _start
        .type   _start, @function

_start:
.LFB0:
        mov rax, 1 # write
        mov rdi, 1 # stdout
        lea rsi, .LC0 # addr
        mov rdx, 14 #length
        syscall

        xor rdi, rdi # rdi = 0
        mov rax, 60 # exit
        syscall