Hello world example in x86 assembly language for FreeBSD

This example program illustrates "Hello world" for the FreeBSD operating system in x86 assembly language.

        .global _start

        .text
_start:
        # write (1, message, 13)
        push    $13               # Number of bytes
        push    $message          # Address of string to output
        push    $1                # File handle 1 is stdout
        mov     $4, %eax          # System call 4 is write
        push    %eax
        int     $0x80

        # exit (0)
        push    $0                # Exit status
        mov     $1, %eax          # System call 1 is exit
        push    %eax
        int     $0x80

message:
        .ascii  "Hello, world\n"

(download)

To compile and run the program, use

cc -c hello.s && ld hello.o && ./a.out

Web links

• GNU Assembler Examples

  This page is an adaption of the assembly language "Hello World" program from the above.

• FreeBSD Developers' Handbook Chapter 11. x86 Assembly Language Programming, 11.3. System Calls

  This page explains the calling conventions of FreeBSD, but using a different assembler.

• FreeBSD Assembly Language Programming

  This page from 2001 explains FreeBSD assembly language programming.