とりあえずnasmでHello World

;; nasm -f elf hello.asm

;; ld hello.o -o hello

;; ./hello

section .data                   ; define data section

msg     db      'Hello World!!',0Ah

len     equ     $-msg           ; length of msg


section .text                   ; define code section

global _start                   ; entry point

_start: mov     edx,len         ; length of string

        mov     ecx,msg         ; address of string

        mov     ebx,1           ; set file hundle(1 = standard IO)

        mov     eax,4           ; set to output(sys_write)

        int     0x80            ; call systemcall
        mov     ebx,0           ; return value

        mov     eax,1           ; exit program

        int     0x80            ; call systemcall