Int 33 Fn 0021  - Ms Mouse V6.0+ - Software Reset                          [M]

   AX = 0021h

Return: AX = status
       FFFFh if mouse driver installed
       BX = number of buttons (FFFFh = two buttons)
       0021h if mouse driver not installed

Note:  this call is identical to funtion 00h, but does not reset the mouse

See Also: AX=0000h