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Cache
6-18
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Ways 0 and 1 are still updated on write hits (D in
) and may be pushed or cleared only explicitly
by using specific cache push/invalidate instructions. However, new cache lines cannot be allocated in ways
0 and 1.
Figure 6-8. Data Cache Locking
A: Ways 0 and 1 are filled.
Ways 2 and 3 are invalid.
B: CACR[DHLCK] is set,
locking ways 0 and 1.
C: When a set in Way 2 is
occupied, the set in way 3 is
used for a cacheable access.
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Way 0 Way 1 Way 2 Way 3
Invalid (V = 0)
Valid, not modified (V = 1, M = 0)
Valid, modified (V = 1, M = 1)
After reset, the cache is
invalidated, ways 0 and 1 are
then written with data that
should not be deallocated.
Ways 0 and 1 can be filled
systematically by using the
INTOUCH instruction.
After CACR[DHLCK] is set,
subsequent cache accesses
go to ways 2 and 3.
Set 0
While the cache is locked
and after a position in ways 2
is full, the set in Way 3 is
updated.
D: Write hits to ways 0 and 1
update cache lines.
Way 0 Way 1 Way 2 Way 3
While the cache is locked,
ways 0 and 1 can be updated
by write hits. In this example,
memory is configured as
copyback, so updated cache
lines are marked modified.
Set 255
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 ...