Avago Technologies LSI53C1010R - Manual (Page 269)

I/O Instructions 5-21
Version 2.2 Copyright © 2000–2003 by LSI Logic Corporation. All rights reserved.
•
The I/O data structure must lie within the 8 Mbytes
above or below the base address.
•
An I/O command structure must have all four bytes
contiguous in system memory, as follows. The
offset/period bits are ordered as in the
SCSI Transfer (SXFER) register. The configuration bits
are ordered as in the SCSI Control Three (SCNTL3)
register.
Use this bit only in conjunction with the Select, Reselect,
Wait Select, and Wait Reselect instructions. It is allowable
to set bits 25 and 26 individually or in combination:
Direct
Uses the device ID and physical address in the instruction.
Table Indirect
Uses the physical jump address, but fetches data using
the table indirect method.
Relative
Uses the device ID in the instruction, but treats the
alternate address as a relative jump.
Config ID Offset/period 00
Bit 25 Bit 26
Direct 0 0
Table Indirect 0 1
Relative 1 0
Table Relative 1 1
Command ID Not Used Not Used
Absolute Alternate Address
Command Table Offset
Absolute Alternate Address