7: Memory Management Unit
7-10
EPSON
ARM720T CORE CPU MANUAL
7.3.7
Translating section references
Figure 7-8 shows the complete section translation sequence.
Figure 7-8 Section translation
Note:
You must check access permissions contained in the level one descriptor before
generating the physical address.
7.3.8
Level two descriptor
If the level one fetch returns either a coarse page table descriptor or a fine page table
descriptor, this provides the base address of the page table to be used. The page table is then
accessed and a level two descriptor is returned. Figure 7-9 shows the format of level two
descriptors.
Figure 7-9 Level two descriptor
31
14 13
0
Translation base
31
14 13
2 1 0
0 0
Table index
Translation base
Modified virtual address
Translation table base
31
20 19
0
Table index
Section index
31
20 19
0
Section index
Section base address
Section level one descriptor
Physical address
31
20 19
0
Section base address
AP
Domain 1 C B 1 0
2 1
3
4
5
8
9
10
11
12
31
12 11 10 9 8
5 4 3 2 1 0
0 0
Large page base address
0 1
Small page base address
C B 1 0
Tiny page base address
1 1
Fault
Large page
Small page
Tiny page
7 6
16 15
B
C
C B
ap0
ap0
ap
ap1
ap2
ap3
ap1
ap2
ap3
Summary of Contents for ARM720T Core cpu
Page 4: ......
Page 12: ...CONTENTS viii EPSON ARM DDI 0229B THIS PAGE IS BLANK ...
Page 13: ...Preface ...
Page 14: ......
Page 18: ...Preface xiv EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 19: ...1 Introduction ...
Page 20: ......
Page 39: ...2 Programmer s Model ...
Page 40: ......
Page 58: ...2 Programmer s Model 2 18 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 59: ...3 Configuration ...
Page 60: ......
Page 70: ...3 Configuration 3 10 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 71: ...4 Instruction and Data Cache ...
Page 72: ......
Page 75: ...5 Write Buffer ...
Page 76: ......
Page 79: ...6 The Bus Interface ...
Page 80: ......
Page 94: ...6 The Bus Interface 6 14 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 95: ...7 Memory Management Unit ...
Page 96: ......
Page 118: ...7 Memory Management Unit 7 22 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 119: ...8 Coprocessor Interface ...
Page 120: ......
Page 131: ...9 Debugging Your System ...
Page 132: ......
Page 177: ...10 ETM Interface ...
Page 178: ......
Page 182: ...10 ETM Interface 10 4 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 183: ...11 Test Support ...
Page 184: ......
Page 198: ...11 Test Support 11 14 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 199: ...Appendix A Signal Descriptions ...
Page 200: ......
Page 208: ...A Signal Descriptions A 8 EPSON ARM720T CORE CPU MANUAL THIS PAGE IS BLANK ...
Page 209: ...Glossary ...
Page 210: ......
Page 217: ...Index ...
Page 218: ......