32.8.118 GMAC Screening Type 2 Compare Word 1 Register x

Table 32-133. Register Bit Attribute Legend
SymbolDescriptionSymbolDescriptionSymbolDescription
RReadable bitHCCleared by Hardware(Grey cell)Unimplemented
WWritable bitHSSet by HardwareXBit is unknown at Reset
KWrite to clearSSoftware settable bit
Name: SCRT2CMP1
Offset: 0x1704 + n*0x08 [n=0..23]
Reset: 0x00000000
Property: Read/Write

Bit 3130292827262524 
          
Access  
Reset  
Bit 2322212019181716 
          
Access  
Reset  
Bit 15141312111098 
        OFFSSTRT[1] 
Access R/W 
Reset 0 
Bit 76543210 
 OFFSSTRT[0]OFFSVAL[6:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 8:7 – OFFSSTRT[1:0] Ethernet Frame Offset Start

ValueNameDescription
0FRAMESTART

Offset from the start of the frame

1ETHERTYPE

Offset from the byte after the EtherType field

2IP

Offset from the byte after the IP header field

3TCP_UDP

Offset from the byte after the TCP/UDP header field

Bits 6:0 – OFFSVAL[6:0] 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.