HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                  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

Esc or Alt-X to exit EBDA Home/PgUp/PgDn/End ←↑↓→
Converted to HTML in 2006 by Timo Bingmann