System Control
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
4-19
ID073015
Non-Confidential
4.3.2
TLB Type Register
The TLBTR characteristics are:
Purpose
Returns the number of lockable entries for the TLB.
Usage constraints
The TLBTR is:
•
common to the Secure and Non-secure states
•
only accessible in privileged mode.
Configurations
Available in all configurations.
Attributes
See the register summary in
.
shows the TLBTR bit assignments.
Figure 4-2 TLBTR bit assignments
shows the TLBTR bit assignments.
To access the TLBTR, read the CP15 register with:
MRC p15,0,<Rd>,c0,c0,3; returns TLB details
4.3.3
Multiprocessor Affinity Register
The MPIDR characteristics are:
Purpose
To identify:
•
whether the processor is part of a Cortex-A9 MPCore
implementation
31
24 23
16 15
8 7
3 2 1 0
SBZ/UNP
DLSize
ILSize
SBZ
TLB_size
nU
Table 4-29 TLBTR bit assignments
Bits
Name
Function
[31:24]
SBZ -
[23:16]
ILsize
Specifies the number of instruction TLB lockable entries.
For the Cortex-A9 processor, this is 0.
[15:8]
DLsize
Specifies the number of unified or data TLB lockable entries.
For the Cortex-A9 processor, this is 4.
[7:3]
SBZ or UNP
-
[2:1]
TLB_size
00
TLB has 64 entries
01
TLB has 128 entries
10
TLB has 256 entries
11
TLB has 512 entries.
[0]
nU
Specifies if the TLB is unified, 0, or if there are separate instruction and data TLBs.
0
The Cortex-A9 processor has a unified TLB.