Instruction and Data Caches
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
7-5
Figure 7-2. MPC885 Data Cache Organization
Each cache block contains four contiguous words from memory that are loaded from a four-word
boundary, that is, bits A[30–31] of the logical (effective) addresses are zero. As a result, cache blocks are
aligned with page boundaries. Note that address bits A[20–27] provide the index to select a cache set for
the MPC885. Bits A[28–29] select a word within a block. The tags consist of the high-order physical
address bits PA[0–19]. Address translation occurs in parallel with set selection (from A[20–27]).
COMP
Way0
28
31
27
20
19
0
Bidirectional Multiplexer 2 -> 1
Hit0
HIT
Data Effective Address
. .
. .
. .
. .
Set0
Set1
Set255
Set254
COMP
Tag0
w0 w1 w2 w3
Va
lid
B
it
L
o
ck B
it
Tag1
w0 w1 w2 w3
Tag255
w0 w1 w2 w3
Tag254
w0 w1 w2 w3
. .
.
. .
.
. .
.
. .
.
L
R
U
A
r
r
a
y
. .
. .
. .
. .
Hit1
To/From Block Buffer
w2
Tag0
w0 w1 w2 w3
Way1
Tag1
w0 w1 w2 w3
Tag255
w0 w1 w2 w3
Tag254
w0 w1 w2 w3
. .
.
. .
.
. .
.
. .
.
Va
lid
B
it
L
o
ck B
it
w2
MMU
8
20
20
128
128
20
128
Di
rt
y
Bi
t
Di
rt
y
Bi
t
8 Bits
Word Select
2
29 30
2
Reserved
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...