Format of FGDRIVER MOUSEPOS variable pointer record:
Offset	Size	Description	)
 00h	WORD	segment of WORD buffer for mouse column
 02h	WORD	offset of WORD buffer for mouse column
 04h	WORD	segment of WORD buffer for mouse row
 06h	WORD	offset of WORD buffer for mouse row
 08h	WORD	segment of WORD buffer for button status
 0Ah	WORD	offset of WORD buffer for button status
Note:	button status: bit 0 = left button, bit 1 = right, bit 2 = middle