System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-47
ID021414
Non-Confidential
4.3.26
Cache Type Register
The CTR_EL0 characteristics are:
Purpose
Provides information about the architecture of the caches.
Usage constraints
This register is accessible as follows:
This register is accessible at EL0 when SCTLR_EL1.UCT is set to 1.
Configurations
CTR_EL0 is architecturally mapped to AArch32 register CTR. See
Cache
Type Register
on page 4-188
.
Attributes
CTR_EL0 is a 32-bit register.
Figure 4-24
shows the CTR_EL0 bit assignments.
Figure 4-24 CTR_EL0 bit assignments
Table 4-59
shows the CTR_EL0 bit assignments.
To access the CTR_EL0:
EL0
EL1
(NS)
EL1
(S)
EL2
EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
Config
RO
RO
RO
RO
RO
IminLine
31 30
28 27
24 23
20 19
16 15 14 13
4 3
0
RES
0
CWG
ERG
DminLine
L1Ip
RES
0
RES
1
Table 4-59 CTR_EL0 bit assignments
Bits
Name
Function
[31]
-
Reserved,
RES
1.
[30:28]
-
Reserved,
RES
0.
[27:24]
CWG
Cache Write-Back granule. Log
2
of the number of words of the maximum size of memory that can be
overwritten as a result of the eviction of a cache entry that has had a memory location in it modified:
0x4
Cache Write-Back granule size is 16 words.
[23:20]
ERG
Exclusives Reservation Granule. Log
2
of the number of words of the maximum size of the reservation granule
that has been implemented for the Load-Exclusive and Store-Exclusive instructions:
0x4
Exclusive reservation granule size is 16 words.
[19:16]
DminLine
Log
2
of the number of words in the smallest cache line of all the data and unified caches that the processor
controls:
0x4
Smallest data cache line size is 16 words.
[15:14]
L1lp
L1 Instruction cache policy. Indicates the indexing and tagging policy for the L1 Instruction cache:
0b10
Virtually Indexed Physically Tagged
(VIPT).
[13:4]
-
Reserved,
RES
0.
[3:0]
IminLine
Log
2
of the number of words in the smallest cache line of all the instruction caches that the processor controls.
0x4
Smallest instruction cache line size is 16 words.