Intel CONTROLLERS 413808 - Manual (Page 256)

Intel
®
413808 and 413812—Address Translation Unit (PCI Express)
Intel ® 413808 and 413812 I/O Controllers in TPER Mode
Developer’s Manual October 2007
256 Order Number: 317805-001US
3.4.2 Outbound Byte Swapping
When enabled, the swapping occurs as described in Figure 29, “Outbound Byte
Swapping for Transaction with Byte Count of 1” on page 256 , Figure 30, “Outbound
Byte Swapping for Transactions with Byte Count of 2” on page 256 , and Figure 31,
“Outbound Byte Swapping Transaction with Byte Count of 3 or Larger” on page 256 .
The bytes are swapped within a 32-bit DWORD and the type of byte swapping
performed is determined by the transaction byte count. For Byte Count of 3 or larger
transactions, no byte swapping is performed.
Note: The byte swapping capability of the ADMA unit should be used to swap bytes within
each DWORD for PCI-to-Memory Read/Write DMA transfers.
Figure 29. Outbound Byte Swapping for Transaction with Byte Count of 1
Figure 30. Outbound Byte Swapping for Transactions with Byte Count of 2
Figure 31. Outbound Byte Swapping Transaction with Byte Count of 3 or Larger
Byte 0 Byte 0
Word 0 [31:24] Word 0 [23:16] Word 0 [15:8] Word 0 [7:0]
Word 0 [7:0] Word 0 [15:8] Word 0 [23:16] Word 0 [31:24]
32-Bit Word on Internal Data Bus
32-Bit Word on PCI Bus
+3 +2 +1 +0 B6199-01
Byte 0 Byte 0 Word 0 [31:24] Word 0 [23:16] Word 0 [15:8] Word 0 [7:0]
Word 0 [15:8] Word 0 [7:0] Word 0 [31:24] Word 0 [23:16]
32-Bit Word on Internal Data Bus
32-Bit Word on PCI Bus
+3 +2 +1 +0 B6200-01
Byte 0 Byte 0 Word 0 [31:24] Word 0 [23:16] Word 0 [15:8] Word 0 [7:0]
Word 0 [31:24] Word 0 [23:16] Word 0 [15:8] Word 0 [7:0]
32-Bit Word on Internal Data Bus
32-Bit Word on PCI Bus
+3 +2 +1 +0 B6201-01