HelloWorld in x86_64 assembly

hello.S

# as -o hello.o hello.S ; cc -o hello hello.o -nostdlib
  .text
  .globl _start
  .type  _start, @function
_start:
  movl $1,    %eax  # sys_write(
  movl $1,    %edi  # fd = stdout,
  movl $.LC0, %esi  # buf = LC0,
  movl $12,   %edx     # 12);
  syscall
  mov $60, %eax     # sys_exit(
  mov $0,  %edi     # 0);
  syscall
.LC0:
  .string	"Hello World\n"