Figure 7-2 – Epson ARM.POWERED ARM720T User Manual
Page 101
7: Memory Management Unit
ARM720T CORE CPU MANUAL
EPSON
7-5
The translation table has up to 4096 x 32-bit entries, each describing 1MB of virtual memory.
This enables up to 4GB of virtual memory to be addressed. Figure 7-2 shows the table walk
process.
Figure 7-2 Translating page tables
Translation
table
4096 entries
TTB base
Indexed by
modified
virtual
address
bits [31:20]
Level one fetch
Section
1 MB
Indexed by
modified
virtual
address
bits [19:0]
Section base
Coarse page table
256 entries
Fine page table
1024 entries
Indexed by
modified
virtual
address
bits [19:12]
Indexed by
modified
virtual
address
bits [19:10]
Coarse page
table base
Fine page
table base
Level two fetch
Large page
64 KB
Small page
4 KB
Tiny page
1 KB
Large page base
Indexed by
modified
virtual
address
bits [15:0]
Indexed by
modified
virtual
address
bits [11:0]
Indexed by
modified
virtual
address
bits [9:0]
00
01
10
11
Invalid
00
10
01
11
00
10
01
11
1 KB subpage
1 KB subpage
1 KB subpage
1 KB subpage
16 KB subpage
16 KB subpage
16 KB subpage
16 KB subpage
Small page base
Tiny page base
Invalid
Invalid
Invalid