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Cache
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6-25
the current state is modified.
6.4.8
CPUSHL Enhancements
The extended CPUSHL functionality adds two new bits in the cache control register (CACR) to support a
set search using a physical address. In particular, the added CACR bits are defined as:
cacr[14] = cacr[SPA] cpushl Search by physical address
cacr[20] = cacr[IVO] cpushl Invalidate only
Cache push
(C,W)V6
No action;
go to invalid state.
Cache push
(C,W)V7
No action;
stay in valid state.
Table 6-9. Data Cache Line State Transitions (Current State Modified)
Access
Response
Read miss
CD1
Push modified line to buffer;
read new line from memory and update cache;
supply data to processor;
write push buffer contents to memory;
go to valid state.
Read hit
CD2
Supply data to processor;
stay in modified state.
Write miss
(copyback)
CD3
Push modified line to buffer;
read new line from memory and update cache;
write push buffer contents to memory;
stay in modified state.
Write miss
(write-through)
WD3 Write data to memory;
stay in modified state.
Cache mode changed for the region corresponding to this line. To avoid this state, execute
a CPUSHL instruction or set CACR[DCINVA,ICINVA] before switching modes.
Write hit
(copyback)
CD4
Write data to cache;
stay in modified state.
Write hit
(write-through)
WD4 Write data to memory and to cache;
go to valid state.
Cache mode changed for the region corresponding to this line. To avoid this state, execute
a CPUSHL instruction or set CACR[DCINVA,ICINVA] before switching modes.
Cache invalidate
CD5
No action (modified data lost);
go to invalid state.
Cache push
CD6
Push modified line to memory;
go to invalid state.
Cache push
CD7
Push modified line to memory;
go to valid state.
Table 6-8. Data Cache Line State Transitions (Current State Valid) (continued)
Access
Response
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...