you could probably do a macro or a template with it I'd imagine.  vaguely
looking like

macro make_multiboot(args: varargs[untyped]): untyped =
  assert len(args) % 2 == 0, "options must be a multiple of two"

  var s = ".align 4\nmultiboot_header:....."
  var i = 0
  while i < len(args):
    s &= ".short " & args[i] & "\n"
    s &= ".long " & args[i+1] & "\n"
    i.inc(2)

  result = quote do:
    asm \`s\`


proc entry..
  asm """jmp multiboot_entry"""
  make_multiboot(0, 8)