GMAC Screening Type 2 Compare Word 1 Register x
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| Access | |||||||||
| Reset |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| OFFSSTRT[1] | |||||||||
| Access | |||||||||
| Reset | 0 |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| OFFSSTRT[0] | OFFSVAL[6:0] | ||||||||
| Access | |||||||||
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Offset Value in Bytes
The value of OFFSVAL ranges from 0 to 127 bytes, and is counted from either the start of the frame, the byte after the EtherType field (last EtherType in the header if the frame is VLAN tagged), the byte after the IP header (IPv4 or IPv6) or the byte after the TCP/UDP header.
Ethernet Frame Offset Start
| Value | Name | Description |
|---|---|---|
| 0 | FRAMESTART |
Offset from the start of the frame |
| 1 | ETHERTYPE |
Offset from the byte after the EtherType field |
| 2 | IP |
Offset from the byte after the IP header field |
| 3 | TCP_UDP |
Offset from the byte after the TCP/UDP header field |