82583V Datasheet, PDF (119/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

Inline Functions—82583V GbE Controller
7.1.4.1
Buffer Address (64-Bit, Offset 0.0)
The field contains the physical address of the receive data buffer. The size of the buffer
is defined by the RCTL register (RCTL.BSIZE, RCTL.BSEX, RCTL.DTYP and RCTL.
FLXBUF fields).
7.1.4.2
Note:
DD (1-Bit, Offset 8.0)
This is the location of the DD bit in the Status field. The software device driver must
clear this bit before it handles the receive descriptor to the 82583V. The software
device driver can use this bit field later on as a completion indication of the hardware.
Descriptor Write-Back Format:
63
48 47
32 31
20 19
0
0
Reserved
MRQ
Packet Checksum
IP Identification
8
VLAN Tag
Length
Extended Error
Extended Status
Light-blue fields are mutually exclusive by RXCSUM.PCSD
7.1.4.3
MRQ Field (32-Bit, Offset 0.0)
Field
Reserved
Reserved
Reserved
Reserved
Bit(s)
3:0
7:4
12:8
31:13
Reserved
Reserved
Reserved
Reserved
Description
7.1.4.4
Packet Checksum (16-Bit, Offset 0.48)
For standard 802.3 packets (non-VLAN) the packet checksum is by default computed
over the entire packet from the first byte of the DA through the last byte of the CRC,
including the Ethernet and IP headers. Software can modify the starting offset for the
packet checksum calculation via the Receive Checksum Control register (RXCSUM).
This register is described in section 9.2.5.15. To verify the TCP/UDP checksum using
the packet checksum, software must adjust the packet checksum value to back out the
bytes that are not part of the true TCP checksum. Likewise, for fragmented UDP
packets, the Packet Checksum field can be used to accelerate UDP checksum
verification by the host processor. This operation is enabled by the RXCSUM.IPPCSE bit
as described in section 9.2.5.15.
For packets with VLAN header the packet checksum includes the header if VLAN
striping is not enabled by the CTRL.VME bit. If VLAN header strip is enabled, the packet
checksum and the starting offset of the packet checksum exclude the VLAN header.
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