; Exec the cmdline at SI or 0x81
exec_chain:
  mov si, 0x81
exec:
  push bx
  sub sp, 0x20
  mov bx, sp

  call fcb_parse
  call fcb_open_blockdev
  mov cx, 5
.loop:
  call fcb_getc
  loop .loop

  add sp, 0x20
  pop bx
  ret