BareMetal OS - Hello World example

[BITS 64]
[ORG 0x0000000000200000]

%INCLUDE "bmdev.asm"

start:					; Start of program label

	mov rsi, hello_message		; Load RSI with memory address of string
	call os_print_string		; Print the string that RSI points to

ret					; Return to OS

hello_message: db 'Hello, world!', 13, 0

This example program will compile to a 31 byte binary. The actual code compiles to 16 bytes and the string is 15 bytes.