INT 33H 0000H: Reset/Query Installed State

 Expects: AX    0000H
 Returns: AX    Mouse installed status: 0000H = not installed (don't use!)
                                        FFFFH = installed
          BX    number of mouse buttons
    Info: Resets the mouse.  Use this function to determine if mouse
          support is present.  It performs a hardware and software reset
          (see INT 33H 0021H for a way to performs just a software reset).

          For text-mode applications, this function does the following:

          • Moves the mouse pointer to the center of the screen
          • Hides the pointer (use INT 33H 0001H to display it).
          • Clears any "exclusion area" set via INT 33H 0010H.
          • Sets the pointer mask to the default: inverse-attribute of
            character at pointer (use INT 33H 000aH to change the
            appearance of the pointer).
          • Sets the range to the height and width of the entire screen
            (use INT 33H 0007H, and INT 33H 0008H or INT 33H 0010H to limit
            the mouse pointer display area).
          • Sets up for pointer drawing on video pg 0 (see INT 33H 001dH).
          • Enables Lightpen emulation (see INT 33H 000dH).
          • Sets pointer speed ratio to horizontal: 8 to 8; vertical 8 to
            16 and sets the maximum doubling threshold to 64 mickeys
            (see INT 33H 001aH).

See Also: INT 33H: Mouse Support
          Interrupts and BIOS Services