1 1 ; nasm -f elf hello.asm # this will produce hello.o ELF object file 2 2 ; ld -s -o hello hello.o # this will produce hello executable 3 3 4 4 section .text 5 5 global _start ;must be declared for linker (ld) 6 6 7 7 _start: ;tell linker entry point 8 8 9 9 00000000 BA0E000000 mov edx,len ;message length 10 10 00000005 B9[00000000] mov ecx,msg ;message to write 11 11 0000000A BB01000000 mov ebx,1 ;file descriptor (stdout) 12 12 0000000F B804000000 mov eax,4 ;system call number (sys_write) 13 13 00000014 CD80 int 0x80 ;call kernel 14 14 15 15 00000016 B801000000 mov eax,1 ;system call number (sys_exit) 16 16 0000001B CD80 int 0x80 ;call kernel 17 17 18 18 section .data 19 19 20 20 00000000 48656C6C6F2C20776F- msg db 'Hello, world!',0xa ;our dear string 21 21 00000009 726C64210A 22 22 len equ $ - msg ;length of our dear string 23 23 24