EBDA - Extended BIOS Data Area EBDA (PS/2)

     Offset	 Size		 Description

	00	 word	   number of bytes allocated to EBDA in Kbytes
	01-21	 21bytes   reserved
	22	 dword	   device driver far call pointer
	26	 byte	   pointing device flag (1st byte, see below)
	27	 byte	   pointing device flag (2nd byte, see below)
	28-2F	 8 bytes   reserved


		Pointing Device Flag Byte 1

		│7│6│5│4│3│2│1│0│ Offset 26
		 │ │ │ │ │ └─┴─┴─── index count
		 │ │ │ │ └──────── reserved (0)
		 │ │ │ └───────── error
		 │ │ └────────── acknowledge
		 │ └─────────── resend
		 └──────────── command in progress

		Pointing Device Flag Byte 2

		│7│6│5│4│3│2│1│0│ Offset 27
		 │ │ │ │ │ └─┴─┴─── package size
		 │ └─┴─┴─┴──────── reserved
		 └─────────────── device driver far call flag


	- EBDA is located in highest memory just under 640K on PS/2
	- word at BIOS Data Area 40:0E is segment address of EBDA