format MS COFF

extrn __imp__MessageBoxA@16:dword
MessageBox equ __imp__MessageBoxA@16

section '.text' code readable executable

 public _demo

 _demo:
	push	0
	push	_caption
	push	_message
	push	0
	call	[MessageBox]
	ret

section '.data' data readable writeable

 _caption db 'Win32 assembly',0
 _message db 'Coffee time!',0