12.9 System Interface Commands and Data Identifiers

System Interface Command Syntax

Figure 12-42 System Interface Command Syntax Bit Definition

SysCmd(8) must be set to 0 for all System interface commands.

SysCmd(7:5) specify the System interface request type which may be read, write, null, invalidate, update, intervention, or snoop; Table 12-11 lists the encoding of SysCmd(7:5).

Table 12-11 shows the types of requests encoded by the SysCmd(7:5) bits.

Table 12-11 Encoding of SysCmd(7:5) for System Interface Commands

SysCmd(4:0) are specific to each type of request and are defined in each of the following sections.

Read Requests

Figure 12-43 Read Request SysCmd Bus Bit Definition

Tables 12-12 through 12-14 list the encodings of SysCmd(4:0) for read requests.

Table 12-12 Encoding of SysCmd(4:3) for Read Requests

Table 12-13 Encoding of SysCmd(2:0) for Coherent and Noncoherent
Block Read Request

Table 12-14 Doubleword, Word, or Partial-word Read Request Data Size
Encoding of SysCmd(2:0)

Write Requests

Table 12-15 lists the write attributes encoded in bits SysCmd(4:3). Table 12-16 lists the block write replacement attributes encoded in bits SysCmd(2:0). Table 12-17 lists the write request bit encodings in SysCmd(2:0).

Figure 12-44 Write Request SysCmd Bus Bit Definition

Table 12-15 Write Request Encoding of SysCmd(4:3)

Table 12-16 Block Write Request Encoding of SysCmd(2:0)

Table 12-17 Doubleword,Word, or Partial-word Write Request Data Size
Encoding of SysCmd(2:0)

Null Requests

Figure 12-45 Null Request SysCmd Bus Bit Definition

Processor null write requests, System interface release external null requests, and secondary cache release external null requests all use the null request command. Table 12-18 lists the encodings of SysCmd(4:3) for processor null write requests. Table 12-19 lists the encodings of SysCmd(4:3) for external null requests.

SysCmd(2:0) are reserved for both instances of null requests.

Table 12-18 Processor Null Write Request Encoding of SysCmd(4:3)

Table 12-19 External Null Request Encoding of SysCmd(4:3)

Invalidate Requests

SysCmd(4:0) are reserved on a processor invalidate request.

Figure 12-46 Invalidate Request SysCmd Bus Bit Definition

Table 12-20 Encoding of SysCmd(4:0) for External Invalidate Requests

Update Requests

Figure 12-47 Update Request SysCmd Bus Bit Definition

Table 12-21 lists the encodings of SysCmd(4:0) for external update requests. Table 12-22 lists the encodings of SysCmd(4:0) for processor update requests. The remaining upper bits are the same for both processor and external update requests.

Table 12-21 Encoding of SysCmd(4:0) for External Update Requests

Table 12-22 Encoding of SysCmd(4:0) for Processor Update Requests

Intervention and Snoop Requests

Figure 12-48 Intervention Request SysCmd Bus Bit Definition

Table 12-23 Encodings of SysCmd(4:0) for Intervention Requests

Figure 12-49 Snoop Request SysCmd Bus Bit Definition

Table 12-24 Encodings of SysCmd(4:0) for Snoop Requests

Generated with CERN WebMaker