Int 15 Fn 53B0  - Intel System Management Bus - Request Data And Status    [X]

   AX = 53B0h
   BH = 13h
   BL = protocol (see #0413)
   CH = device address
   CL = device command

Return: CF clear if successful
       AH = 00h (SMBus OK)
       CH = status
       00h no data pending, transaction complete
       01h no data pending, transaction continues
       02h data pending
       CL = number of valid bytes in DX (0-2)
       DH = MSB data
       DL = LSB data
   CF set if error
       AH = error code (05h,10h,11h,13h,15h,16h,18h,1Bh,86h) (see #0410)
Desc:  determine when a transaction is complete, gather data returned by read
     transactions

Note:  for Block Read protocol (08h), first call returns block length in DH
     and the first byte of the block in DL