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7: Memory Management Unit
7.3.9
Translating large page references
Figure 7-10 shows the complete translation sequence for a 64KB large page.
31
Translation base
31
Translation base
31
Coarse page table base address
31
Coarse page table base address
31
Page base address
31
Page base address
Figure 7-10 Large page translation from a coarse page table
Because the upper four bits of the page index and low-order four bits of the coarse page table
index overlap, each coarse page table entry for a large page must be duplicated 16 times (in
consecutive memory locations) in the coarse page table.
If a large page descriptor is included in a fine page table, the high-order six bits of the page
index and low-order six bits of the fine page table index overlap. Each fine page table entry for
a large page must therefore be duplicated 64 times.
7-12
31
Table index
Translation table base
14 13
14 13
Table index
Level one descriptor
10
9
10
9
Level two descriptor
16 15
12
11
10
9
ap3
ap2 ap1 ap0
Physical address
16 15
Page index
EPSON
Modified virtual address
20 19
16 15
L2
table index
0
2 1 0
0 0
8
5
4
3
2 1
0
Domain 1
0
1
2 1
0
L2 table index
0
0
8
7
6
5
4
3
2
1
0
C B
0
1
0
12 11
Page index
ARM720T CORE CPU MANUAL
0
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