Sun Microsystems UltraSPARC-I User Manual page 156

7.17.2 Packet Description
7.17.2.1 Master ID (MID)
MID is a 5-bit field. It identifies the source Interconnect master port that made
this request. MasterID is the same as the port_ID bits. SC can be useMID to main-
tain ordering for transactions with the same MID, and to parallelize requests with
different MIDs.
If the system forwards the request to a slave UltraSPARC for proxy execution, the
slave maintains the MID and returns it to SC in the P_REPLY packet.
7.17.2.2 Transaction Type
This 4-bit field encodes the transaction type, as shown in Table 7-37.
Table 7-37
Transaction Type
P_RDS_REQ
P_RDSA_REQ
P_RDO_REQ
P_RDD_REQ
S_CPB_MSI_REQ
P_NCRD_REQ
P_NCBRD_REQ
P_NCBWR_REQ
P_WRB_REQ
P_WRI_REQ
S_INV_REQ
S_CPB_REQ
S_CPI_REQ
S_CPD_REQ
P_NCWR_REQ
P_INT_REQ
7.17.2.3 Class
The Class bit identifies which of the two master Class queues the request has
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been issued from. The system must maintain strong ordering between transac-
Interconnect Transaction Type Encoding
Name
ReadToShare
ReadtoShareAlways
ReadToOwn
ReadToDiscard
CopybackGotoSstate
NonCachedRead
NonCachedBlockRead
NonCachedBlockWrite
Writeback
WritebackInvalidate
Invalidate
Copyback
CopybackInvalidate
CopybackToDiscard
NonCachedWrite
Interrupt
7. UltraSPARC External Interfaces
Type
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111