Memory Management Unit
ARM DDI 0301H Copyright © 2004-2009 ARM Limited. All rights reserved. 6-52
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Figure 6-18 4KB extended small page or 1KB extended small subpage translations, backwards-compatible format
Using backwards-compatible descriptors, the 4KB extended small page is generated by setting
all of the AP bit pairs to the same values, AP3=AP2=AP1=AP0. If any one of the pairs are
different, then the 4KB extended small page is converted into four 1KB extended small page
subpages. The subpage access permission bits are chosen using the virtual address bits [11:10].
N
S
1
Coarse page table base address
31 1098 54 210
P Domain 0
First-level table index
31 20 19 12 11 0
Second-level
table index
Page index
Translation base
31 14 13 0
1
Extended small page base address
31 1211 98 6543210
SBZ TEX AP C B 1
0
Coarse page table base address
31 10 9 2 1 0
Second-level table
index
0
0
Translation base
31 14 13 0
First-level table index 0
21
Page index
Page base address
31 12 11 0
Second-level descriptor address
Second-level descriptor
Physical address
First-level descriptor
First-level descriptor address
Modified virtual address
Translation table base
3
SBZ SBZ
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