System Control
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
4-22
ID073015
Non-Confidential
Figure 4-5 CCSIDR bit assignments
shows how the CSSIDR bit assignments.
To access the CCSIDR, read the CP15 register with:
MRC p15, 1, <Rd>, c0, c0, 0; Read current Cache Size Identification Register
If the CSSELR reads the instruction cache values, then bits [31:28] are b0010.
If the CSSELR reads the data cache values, then bits [31:28] are b0111. See
4.3.6
Cache Level ID Register
The CLIDR characteristics are:
Purpose
Identifies:
•
the type of cache, or caches, implemented at each level
Line size
31 30 29 28 27
13 12
2
0
NumSets
Associativity
WT
WB
RA
WA
Table 4-32 CCSIDR bit assignments
Bits
Name
Function
[31]
WT
Indicates support available for Write-Through:
0
Write-Through support not available
1
Write-Through support available.
[30]
WB
Indicates support available for Write-Back:
0
Write-Back support not available
1
Write-Back support available.
[29]
RA
Indicates support available for Read-Allocation:
0
Read-Allocation support not available
1
Read-Allocation support available.
[28]
WA
Indicates support available for Write-Allocation:
0
Write-Allocation support not available
1
Write-Allocation support available.
[27:13]
NumSets
Indicates number of sets:
0x7F
16KB cache size
0xFF
32KB cache size
0x1FF
64KB cache size.
[12:3]
Associativity
Indicates number of ways:
b0000000011
Four ways.
[2:0]
LineSize
Indicates number of words:
b001
Eight words per line.