1 cache control register (ccr) – Renesas SH7781 User Manual
Page 246
8. Caches
Rev.1.00 Jan. 10, 2008 Page 216 of 1658
REJ09B0261-0100
8.2.1
Cache Control Register (CCR)
CCR controls the cache operating mode, the cache write mode, and invalidation of all cache
entries.
CCR modifications must only be made by a program in the non-cacheable P2 area or IL memory.
After CCR has been updated, execute one of the following three methods before an access
(including an instruction fetch) to the cacheable area is performed.
1. Execute a branch using the RTE instruction. In this case, the branch destination may be the
cacheable area.
2. Execute the ICBI instruction for any address (including non-cacheable area).
3. If the R2 bit in IRMCR is 0 (initial value) before updating CCR, the specific instruction does
not need to be executed. However, note that the CPU processing performance will be lowered
because the instruction fetch is performed again for the next instruction after CCR has been
updated.
Note that the method 3 may not be guaranteed in the future SuperH Series. Therefore, it is
recommended that the method 1 or 2 should be used for being compatible with the future SuperH
Series.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Bit:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Initial value:
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R/W
R
R
R/W
R
R
R
R
R/W
R/W
R/W
R/W
R/W:
Bit:
Initial value:
R/W:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ICI
ICE
OCE
WT
CB
OCI
0
Bit Bit
Name
Initial
Value R/W
Description
31 to 12
⎯ All
0
R
Reserved
For details on reading from or writing to these bits, see
description in General Precautions on Handling of
Product.
11 ICI
0
R/W
IC
Invalidation
Bit
When 1 is written to this bit, the V bits of all IC entries
are cleared to 0. This bit is always read as 0.