Int 67 Fn 5B  - Lim Ems 4.0 - Alternate Map Register Set - Dma Registers   [m]

   AH = 5Bh
   AL = subfunction
       05h allocate DMA register set

       Return: BL = DMA register set number, 00h if not supported
       06h enable DMA on alternate map register set
          BL = DMA register set number
          DL = DMA channel number
       07h disable DMA on alternate map register set
          BL = DMA register set number
       08h deallocate DMA register set
          BL = DMA register set number

Return: AH = status (00h,80h,81h,84h,8Fh,9Ah-9Fh,A3h,A4h) (see #3327)

Note:  this function is for use by operating systems only, and can be
     enabled or disabled at any time by the operating system