Int 15 Fn C206  - System - Pointing Device BIOS Interface (ps) - Extended  [M]

   AX = C206h
   BH = subfunction
       00h return device status

       Return: BL = pointing device status (see below)
           CL = resolution (see AX=C203h)
           DL = sample rate, reports per second
       01h set scaling at 1:1
       02h set scaling at 2:1

Return: CF set on error
       AH = status (see AX=C200h)

Bitfields for pointing device status:
 bit 0 right button pressed
 bit 1 reserved
 bit 2 left button pressed
 bit 3 reserved
 bit 4 0 if 1:1 scaling, 1 if 2:1 scaling
 bit 5 device enabled
 bit 6 0 if stream mode, 1 if remote mode
 bit 7 reserved