(bind-func static set_lfo_amp
  (lambda (inst:i8* lfo_num:i32 amp:float)
    (let ((krl (if (< lfo_num 4)
                   (cref (cast inst [void]*) effect_kernel [void]*)
                   (cref (cast inst [void]*) note_kernel [void]*)))
          (mod_amp (cref krl mod_amp |4,float|*)))
      (aset! mod_amp (% lfo_num 4) amp))))