R2: translation table base register, R3: domain access control register, Fields – Digi NS9750 User Manual
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R2: Translation Table Base register
Register R2 is the Translation Table Base register (TTBR), for the base address of the
first-level translation table.
Reading from R2 returns the pointer to the currently active first-level
translation table in bits [31:14] and an
UNPREDICTABLE
value in bits [13:0].
Writing to R2 updates the pointer to the first-level translation table from
the value in bits[31:14] of the written value. Bits [13:0]
SHOULD BE ZERO
.
Use these instructions to access the Translation Table Base register:
MRC p15, 0, Rd, c2, c0, 0 ; read TTBR
MCR p15, 0, Rd, c2, c0, 0 ; write TTBR
The
CRm
and
opcode_2
fields
SHOULD BE ZERO
when writing to R2.
Figure 14 shows the format of the Translation Table Base register.
Figure 14: R2: Translation Table Base register
R3: Domain Access Control register
Register R3 is the Domain Access Control register and consists of 16 two-bit fields, as
shown in Figure 15.
Figure 15: R3: Domain Access Control register
Reading from R3 returns the value of the Domain Access Control register.
Writing to R3 writes the value of the Domain Access Control register.
31
0
14 13
Translation table base
UNP/SBZ
31
0
14 13 12 11 10
9
8
7
6
5
4
3
2
1
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15