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User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
Instruction-Cache and Data-Cache Operation
Page 146 of 377
gx_03.fm.(1.2)
March 27, 2006
Table 3-6. Address/Transfer Attribute Summary
Bus Transaction A[0–31] TT[0–4] TBST TSIZ[0–2] GBL WT CI
Instruction fetch operations:
Burst (caching-enabled) PA[0–28] || 0b000 0 1 1 1 0 0 0 1 0 ¬ M 1 1*
Single-beat read (caching-inhibited or
cache disabled)
PA[0–28] || 0b000 0 1 0 1 0 1 0 0 0 ¬ M 1 ¬ I
Single-beat read (caching-inhibited or
cache disabled, 32-bit bus)
PA(0:29) || 00 0 1 0 1 0 1 1 0 0 ¬ M 1 ¬ I
Data-cache operations:
Cache-block fill (due to load or store
miss)
PA[0–28] || 0b000 A 1 1 1 0 0 0 1 0 ¬ M 0 1*
Castout
(normal replacement)
CA[0–26] || 0b00000 0 0 1 1 0 0 0 1 0 1 1 1*
Push (cache-block push due to dcbf or
dcbst)
PA[0–26] || 0b00000 0 0 1 1 0 0 0 1 0 1 0 1*
Snoop copyback CA[0–26] || 0b00000 0 0 1 1 0 0 0 1 0 1 0 1*
Data-cache bypass operations:
Single-beat read (caching-inhibited or
cache disabled)
PA[0–31] A 1 0 1 0 1 S S S ¬ M 0 ¬ I
Single-beat write (caching-inhibited,
write-through, or cache disabled)
PA[0–31] 0 0 0 1 0 1 S S S ¬ M ¬W ¬ I
Special instructions:
dcbz (address-only) PA[0–28] || 0b000 0 1 1 0 0 0 0 1 0 0* 0 1*
dcbi (if HID0[ABE] = 1, address-only) PA[0–26] || 0b00000 0 1 1 0 0 0 0 1 0 ¬ M 0 1*
dcbf (if HID0[ABE] = 1, address-only) PA[0–26] || 0b00000 0 0 1 0 0 0 0 1 0 ¬ M 0 1*
dcbst (if HID0[ABE] = 1, address-only) PA[0–26] || 0b00000 0 0 0 0 0 0 0 1 0 ¬ M 0 1*
sync (if HID0[ABE] = 1, address-only) 0x0000_0000 0 1 0 0 0 0 0 1 0 0 0 0
eieio (if HID0[ABE] = 1, address-only) 0x0000_0000 1 0 0 0 0 0 0 1 0 0 0 0
stwcx. (always single-beat write) PA[0–29] || 0b00 1 0 0 1 0 1 1 0 0 ¬ M ¬ W ¬ I
eciwx PA[0–29] || 0b00 1 1 1 0 0 EAR[28–31] 1 0 0
ecowx PA[0–29] || 0b00 1 0 1 0 0 EAR[28–31] 1 1 0
Note:
PA = Physical address, CA = Cache address.
W,I,M = WIM state from address translation; ¬ = complement; 0*or 1* = WIM state implied by transaction type in table
For instruction fetches, reflection of the M bit must be enabled through HID0[IFEM].
A = Atomic; high if lwarx, low otherwise
S = Transfer size
Special instructions listed might not generate bus transactions depending on cache state.