myOS/programs/hello/hello.asm

[BITS 32]
section .asm
global _start
_start:
    push msg
    mov eax, 1
    int 0x80
    add esp, 4

    jmp $


section .data
    msg db 'Hello world from a user program!', 0xa, 0 ; db - define bytes, 0xa - code of \n