Figure 6-5 Backwards-Compatible Second-Level Descriptor Format; Figure 6-6 Backwards-Compatible Section, Supersection, And Page Translation - ARM ARM1176JZF-S Technical Reference Manual

Translation fault
Large page (64KB)
Small page
(4KB)
Extended small
page (4KB)
ARM DDI 0301H
ID012310
31
Large page base address
Small page base address
Extended small page base address

Figure 6-5 Backwards-compatible second-level descriptor format

For extended small page table entries without a TEX field you must use the value b000. For
details of TEX encodings see C and B bit, and type extension field encodings on page 6-14.
Note
For any Supersection description in a first-level page table, and any Large page description in a
second-level page table:
• you must repeat the description in 16 consecutive page table locations
• the first description must occur on a 16-word boundary
For more information see the ARM Architecture Reference Manual.
Figure 6-6 shows an overview of the section, supersection, and page translation process using
backwards-compatible descriptors.
First level
page table
Translation
table base
Invalid
Indexed by
VA[31:20]
(bit 18 = 0)
(bit 18 = 1) 10

Figure 6-6 Backwards-compatible section, supersection, and page translation

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16 15
Ignored
Coarse page
Base address
31
from L1D[31:10]
00
Indexed by
VA[19:12]
01
1MB section
Base address
10
from L1D[31:20]
Indexed by
VA[19:0]
supersection
Base address
from L1D[31:24]
Indexed by
VA[23:0]
Memory Management Unit
12 11 10 9 8 7 6 5 4 3 2 1 0
TEX AP3 AP2 AP1 AP0 C
AP3 AP2 AP1 AP0 C B 1
SBZ TEX
Base address
table
0
from L2D[31:16]
Invalid 00
Indexed by
VA[15:0]
01
Base address
10
from L2D[31:12]
Indexed by
VA[11:0]
11
Base address
from L2D[31:12]
Indexed by
VA[11:0]
16MB
0 0
B 0 1
0
AP C B 1 1
64KB large page
31 0
16KB subpage
16KB subpage
16KB subpage
16KB subpage
4KB small page
31 0
1KB subpage
1KB subpage
1KB subpage
1KB subpage
4KB extended
small page
31 0
6-38