Agnus/
                  Read/   Denise/
Register Address  Write   Paula         Function
-------- -------  -----   -------       --------
DSKBYTR    01A      R       P     Disk data byte and status read

                 This register is the disk-microprocessor data
                 buffer.  Data from the disk (in read mode) is
                 loaded into this register one byte at a time, and
                 bit 15 (DSKBYT) is set true.

                 BIT#
                 ----  ---------  --------------------------------
                 15    DSKBYT     Disk byte ready (reset on read)
                 14    DMAON      Mirror of bit 15 (DMAEN) in  dsklen ,
                                  ANDed with Bit09 (DMAEN) in  dmacon 
                 13    DISKWRITE  Mirror of bit 14 (WRITE) in  dsklen 
                 12    WORDEQUAL  This bit true only while the
                                   dsksync  register equals the data
                                  from disk.
                 11-08  X         Not used
                 07-00 DATA       Disk byte data