Int 15 Fn C207  - System - Pointing Device BIOS Interface (ps) - Set Devi  [M]

   AX = C207h
   ES:BX -> FAR user device handler

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

Note:  when the subroutine is called, it is passed the following values on
     the stack; the handler should return with a FAR return without
     popping the stack:
       WORD 1: status (see below)
       WORD 2: X data (high byte = 00h)
       WORD 3: Y data (high byte = 00h)
       WORD 4: 0000h

See Also: INT 33/AX=000Ch

Bitfields for status:
 bits 15-8 reserved (0)
 bit 7 Y data overflowed
 bit 6 X data overflowed
 bit 5 Y data is negative
 bit 4 X data is negative
 bit 3 reserved (1)
 bit 2 reserved (0)
 bit 1 right button pressed
 bit 0 left button pressed