global main extern printf section .data global main extern printf section .data message db "Hello World", 10, 0 ; \n\0 section .text main: push dword message mov eax, [esp] mov ecx, 11 jmp unicorn unicorn: xor [eax+ecx-1], byte 0x33 dec ecx ;ecx = 0 -> ZF = 1 jne unicorn push dword message call printf