Direct-Store Transactions - IBM PowerPC 604 User Manual

ADDRESS TENURE
1/0 RESPONSE
ARBITRATION TRANSFER TERMINATION••• ARBITRATION
INDEPENDENT ADDRESS AND DATA
~
DATA TENURE
NO DATA TENURE FOR 1/0 RESPONSE
RBITRATION TRANSFER TERMINATION e • • (l/O responses are address-only)
Figure 8·22. Direct-Store Tenures
8.6.1 Direct-Store Transactions
The 604 defines seven direct-store transaction operations, as shown in Table 8-8. These
operations permit communication between the 604 and BUCs. A single 604 store or load
instruction (that translates to a direct-store access) generates one or more direct-store
operations (two or more direct-store operations for loads) from the 604 and one reply
operation from the addressed BUC.
Table
8-8.
Direct-Store Bus Operations
Operation Address Only Direction XATC Encoding
Load start (request) Yes
604~10
0100 0000
Load immediate
No
604~10
0101 0000
Load last
No 604~10 0111 0000
Store immediate
No
604~10
0001 0000
Store
last
No
604~10
0011 0000
Load reply Yes
10~604
1100 0000
Store reply Yes
10~604
10000000
For the first beat of the address bus, the extended address transfer code (XATC), contains
the 1/0 opcode as shown in Table 8-8; the opcode is formed by concatenating the transfer
type, transfer burst, and transfer size signals defined as follows:
XATC
=
TT[0:3]11TBSTllTSIZ[0:2]
8-40 PowerPC 604 RISC Microprocessor User's Manual