System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-96
ID021414
Non-Confidential
To access the TCR_EL3:
MRS <Xt>, TCR_EL3 ; Read EL3 Translation Control Register
MRS TCR_EL3, <Xt> ; Read EL3 Translation Control Register
[22:21]
-
Reserved,
RES
0.
[20]
TBI
Top Byte Ignored. Indicates whether the top byte of the input address is used for address match.
The possible values are:
0
Top byte used in the address calculation.
1
Top byte ignored in the address calculation.
[19]
-
Reserved,
RES
0.
[18:16]
PS
Physical address size. The possible values are:
0b000
32 bits, 4 GB.
0b001
36 bits, 64 GB.
0b010
40 bits, 1 TB.
Other values are reserved.
[15:14]
TG0
TTBR0_EL3 granule size. The possible values are:
0b00
4 KB.
0b10
64 KB.
[13:12]
SH0
Shareability attribute for memory associated with translation table walks using TTBR0_EL3.
The possible values are:
0b00
Non-shareable.
0b01
Reserved.
0b10
Outer shareable.
0b11
Inner shareable.
[11:10]
ORGN0
Outer cacheability attribute for memory associated with translation table walks using
TTBR0_EL3.
The possible values are:
0b00
Normal memory, Outer Non-cacheable.
0b01
Normal memory, Outer Write-Back Write-Allocate Cacheable.
0b10
Normal memory, Outer Write-Through Cacheable.
0b11
Normal memory, Outer Write-Back no Write-Allocate Cacheable.
[9:8]
IRGN0
Inner cacheability attribute for memory associated with translation table walks using
TTBR0_EL3.
The possible values are:
0b00
Normal memory, Inner Non-cacheable.
0b01
Normal memory, Inner Write-Back Write-Allocate Cacheable.
0b10
Normal memory, Inner Write-Through Cacheable.
0b11
Normal memory, Inner Write-Back no Write-Allocate Cacheable.
[7:6]
-
Reserved,
RES
0.
[5:0]
T0SZ
Size offset of the memory region addressed by TTBR0_EL3. The region size is 2
(64-T0SZ)
bytes.
Table 4-88 TCR_EL3 bit assignments (continued)
Bits
Name
Function