Ciprico Rimfire 3880 manual RF3880 Swapping Options, Intel Ordered Parameter Block

Chapter 8 Details of Usage

Page 8 - 6 Byte and Word Swapping

Note

Offset + x values are in opposite order for Intel Processors

RF3880

Swapping

Options

However, if you have an Intel processor, you must reinterpret the representations in this manual to an order like this:

Address		Byte Memory Address
Offset	Offset + 3	Offset + 2	Offset + 1	Offset + 0
00H		Command Identifier - 04030201H
04H	Flags-2 = 01H	Flags-1 = 86H	Addr. Mod = 3EH	Target ID = 02H
08H		VME Memory Address - 005A9320H
0CH		Transfer Count = 00010280H
10H	0 = 2AH	1 = 40H	2 = 0	3 = 08H
14H	4 = F4H	5 = E9H	6 = 0	7 = 02H
18H	8 = 05H	9 = 0	10 = 0	11 = 0

Table 112: Intel Ordered Parameter Block

In order for this transition to properly occur, more than just your interpretation of the graphics in the manual must change. The RF3880 must be told to also reinterpret the structures it uses.

Byte and Word Swapping methodology for the RF3880 adapter is configured with the Control field of the Address Buffer Port. This field is in the first word written to the Address Buffer Port. (For bit-specific information on the Address Buffer Port see Chapter 2, Hardware Essentials.)

Swapping is a function of the firmware on the RF3880 adapter and is enabled and performed with minimal impact on performance.

There are two bits in the Control field that allow you to separately control byte swapping and word swapping. If you set neither of the swapping bits in the Control field, the Command Structures will be ordered for a standard Motorola processor.

Command Structure Swapping

As explained, the need to byte-swap and word-swap the fields of the RF3880 Command Structures is due to the differences inherent in various processor architectures. Since the RF3880 defaults to using Motorola ordering for its structures, if your system uses a Motorola processor, no byte and word swapping is necessary. However, if your system uses an Intel processor, the Command Structures of the RF3880 must be adjusted.

This could be done entirely in software — the Host processor could re-order the Command Structures. However this extra burden for the system is not necessary because, by simply enabling the Byte and Word Swap controls, the RF3880 adapter will automatically re-order the Command Structures.

21020285 D User’s Guide