Int 15 Fn CE  - Later Ps/2s - Allocate Dma Arbitration Level               [B]

   AH = CEh
   BL = 00h-0Eh arbitration level to be allocated
        0Fh-FFh reserved
   AL = option byte
       bit 7-1: reserved (0)
       bit 0: 0 = need DMA channel for arbitration level requested
          1 = no channel required for arbitration level

Return: CF set on error
       AH = status (80h,86h = function not supported)
   CF clear on success
       AL = channel number
       00h-07h channel number allocated for the arbiration level
       08h-FEh reserved
       FFh no channel requested for arbitration level
       AH = status
       00h success
       01h arbitration level not available
       02h channel not available
       03h invalid arbitration level passed

Notes:  arbitration level 00h has the highest priority, 0Eh the lowest
    to perform a DMA transfer operation, be sure to call this function
      first, and call AH=CFh afterward.  Failure to use this function
      can cause unpredictable results.

See Also: AH=CFh